Suggested answers for those have tried attempted this paper:
REVIEW OF THE 2009 SPM BIOLOGY PAPER 1
1. P is mitochondrion, Q is Rough endoplasmic reticulum, R is chromosome
Answer : C
2. Organelle that synthesizes protein is ribosome
Answer: B
3. P shown in the structure of plasma membrane is a carrier protein.
Answer: D
4. After one hour, there will be a rise in capillary tube because the water molecules from distilled water which is hypotonic has entered the Visking tubing via osmosis.
Answer: C
5. The process X is osmosis because water molecules from distilled water will diffuse through the egg membrane which is a semi permeable membrane.
Answer: A
6. The type of movement of molecules P is facilitated diffusion because it moves along concentration gradient
Answer: D
7. The correct sequence of the production of the extracellular enzyme is R Q P
Answer: C
8. The Diagram which shows the cell has been immersed in a hypotonic solution is the one which shows the largest vacuole.
Answer: C
9. The process of formation of a disaccharide molecule from two monosaccharide is known as condensation.
Answer: B
10. Hydrolysis of protein is represented by the equation D
Answer: D
11. Diagram which shows cell that is produced by the cell division of mitosis is A
Answer: B
12. The stage of the mitotic cell division is metaphase because the chromosomes are aligned at the equatorial plane.
Answer: D
13. The individuals of P is breast feeding mother, Q is construction worker and R is a clerk. This is because a bar chart shows the highest energy requirement for Q, the second highest for P and the least for R
Answer: B
14. The food in Level 1 in a food guide pyramid for a balanced diet is rice which is a carbohydrate.
Answer: B
15. The most suitable menu for those suffering from night blindness are Q,S and T which includes vitamin A
Answer: A
16. The cells in a leaf which transport organic substances and water are N and M which are phloem and xylem respectively.
Answer: C
17. The process shown in a Diagram is assimilation where glucose and amino acid are transported to the body cell.
Answer: A
18.The labeled part which contains beneficial bacteria is colon.
Answer: D
19. The purpose of plucking the leaves from a seedling before transferring it from the nursery to the orchard is to reduce the rate of transpiration.
Answer: C
20. The rate of heart beat after the boy stops running is indicated by part B because the heart beat is back to the normal.
Answer: B
21. Based on Diagram given, the adaptations of alveolus which increase the rate of gaseous exchange include: located close to blood capillaries and covered by a thin film of moisture
Answer: D
22. The processes which occur in the respiratory system of a mountain climber which has dropped from its normal level so that the level is returned to normal are: breathing and ventilation rate increase and respiratory muscles contract and relax faster.
Answer: C
23. The total amount of energy used by the plant is when it is absorbed by plant, and for growth.
Answer: C
24. An equation for an anerobic respiration is P is Glucose, Q is oxygen, R is carbon dioxide, S is water and T is ATP.
Answer: D
25. The immediate effect of smoking on the respiratory surface is dries up the lining of alveoli
Answer: B
26. The correct sequence about a sampling technique to estimate the population size of garden snails in a habitat is capture a large number of garden snails and mark each shell, release the garden snails in the same habitat, capture at random a number of garden snails and record the number which are marked and calculate the population of the garden snails
Answer: A
27. The abiotic components in an ecosystem are humidity and light intensity
Answer: C
28. The correct sequence refers to the thinning of the ozone layer is : CFC leaks out of air conditioner, Ultra violet rays break down CFC molecules, then chlorine atom breaks down ozone molecule.
Answer: D
29. The environmental phenomenon which show the melting of ice at the poles and an increase in sea level is global warming.
Answer: D
30. The procedure to investigate the level of water pollution in a river is:
Fill the reagent bottles with water samples, use a syringe to add 1 ml of methylene blue solution, place the reagent bottles inside a cupboard, then record the time taken for the methylene blue solution to decolorize.
Answer: A
31. B.O.D. value is high in river X shows that the river is polluted.
Answer: A
32. The labeled vascular tissue in a tree trunk is sieve tube.
Answer: B
33. The formation of oxyhaemoglobin takes place in the lungs and the dissociation of it occurs in body cells.
Answer: A
34. The part in the gills of a fish which has the highest rate of gaseous exchange is the lamellae
Answer: C
35. The systemic circulatory system is when the oxygenated blood flows from left ventricle to the body, then deoxygenated blood flows from body to the right atrium.
Answer: C
36. A complete ring of bark is removed from a stem of a woody plant. After a few months, the leaves start to fall off and finally the plant dies. This is because sugar is not transported to the roots.
Answer: B
37. The curve which shows the concentration of the antibody after the 8th week of an individual who was affected with measles is B
Answer: B
38. Substance which is injected into the body to stimulate the production of antibodies is vaccine
Answer: B
39. Bones that make up the pectoral girdle are clavicle and scapula.
Answer: D
40. Substances which moves across synapse is neurotransmitter
Answer: D
41. Structure which carries the impulses towards the spinal cord is afferent neurone
Answer: A
42. Based on graph showing changes in the blood glucose level, the true statement is hormone X which is insulin lower the blood glucose level
Answer: A
43. Part of the brain which controls the breathing process is medula oblongata
Answer: D
44. The formation of female gametes is known as oogenesis
Answer: B
45. In spermatogenesis, the groups of cells which have a haploid number of chromosome is secondary spermatocyte and spermatids.
Answer: D
46. In the development of a follicle in an ovary, the structure which involve in secreting progesterone is corpus luteum.
Answer: C
47. A wife has difficulty in ovulating. The hormone treatment which is the most suitable to help the wife to ovulate is Luteinizing hormone.
Answer: B
48. A boy has blood group A and his sister has blood group B. The correct combination of genotypes belonging to their parents are father: AB, mother: AB
Answer: A
49. After 15 days the Graafian follicle will develop into a corpus luteum.
Answer: C
50. The process of separation of sister chromatids does not cause variation.
Answer: C
Saturday, December 26, 2009
Thursday, December 10, 2009
B.O.D.
In respond to Question 31 Paper 1 SPM 2009 
From a study on river X, this finding is obtained: Biochemical oxygen demand (B.O.D) value is high: Which statement is correct about the river:
1. The river is POLLUTED.
2.The content of dissolved OXYGEN is LOW
3.The river contains LESS/NO living aquatic organisms.
4.The DECOMPOSITION activity by microorganisms is HIGH.
Many students get confused over the B.O.D stuff which is related with the BOD experiment to test the pollution in different water samples..
Microorganisms such as bacteria are responsible for decomposing organic waste. When organic matter such as dead plants, leaves, manure, sewage, or even food waste is present in a water supply, the bacteria will begin the process of breaking down this waste. When this happens, much of the available dissolved oxygen is consumed by aerobic bacteria, robbing other aquatic organisms of the oxygen they need to live.
Biological Oxygen Demand (BOD) is a measure of the oxygen used by microorganisms to decompose this waste. If there is a large quantity of organic waste in the water supply, there will also be a lot of bacteria present working to decompose this waste. In this case, the demand for oxygen will be high (due to all the bacteria) so the BOD level will be high. As the waste is consumed or dispersed through the water, BOD levels will begin to decline.
Nitrates and phosphates in a body of water can contribute to high BOD levels. Nitrates and phosphates are plant nutrients (maybe from organic fertilisers) and can cause plant life and algae to grow quickly. When plants grow quickly, they also die quickly. This contributes to the organic waste in the water, which is then decomposed by bacteria. This results in a high BOD level.
The temperature of the water can also contribute to high BOD levels. For example, warmer water usually will have a higher BOD level than colder water. As water temperature increases, the rate of photosynthesis by algae and other plant life in the water also increases. When this happens, plants grow faster and also die faster. When the plants die, they fall to the bottom where they are decomposed by bacteria. The bacteria require oxygen for this process so the BOD is high at this location. Therefore, increased water temperatures will speed up bacterial decomposition and result in higher BOD levels.
When BOD levels are high, dissolved oxygen (DO) levels decrease because the oxygen that is available in the water is being consumed by the bacteria. Since less dissolved oxygen is available in the water, fish and other aquatic organisms may not survive.
Test Procedure:
The BOD test takes 5 days to complete and is performed using a dissolved oxygen test kit.
The BOD level is determined by comparing the DO level of a water sample taken immediately with the DO level of a water sample that has been incubated in a dark location for 5 days.
The difference between the two DO levels represents the amount of oxygen required for the decomposition of any organic material in the sample and is a good approximation of the BOD level.
6.Record your final BOD result in ppm.
RESULT:
BOD Level(in ppm) Water Quality
1 - 2 Very Good:There will not be much organic waste present in the water supply. 3 - 5 Fair: Moderately Clean
6 - 9 Poor: Somewhat PollutedUsually indicates organic matter is present and
bacteria are decomposing this waste.
100 or greater Very Poor: Very PollutedContains organic waste.
…The more polluted the water sample is, the faster the methylene blue solution to decolorise ..
Notes are extracted..TQ
http://www.ciese.org/curriculum/dipproj2/en/fieldbook/bod.shtml
From a study on river X, this finding is obtained: Biochemical oxygen demand (B.O.D) value is high: Which statement is correct about the river:
1. The river is POLLUTED.
2.The content of dissolved OXYGEN is LOW
3.The river contains LESS/NO living aquatic organisms.
4.The DECOMPOSITION activity by microorganisms is HIGH.
Many students get confused over the B.O.D stuff which is related with the BOD experiment to test the pollution in different water samples..
Biochemical oxygen demand or BOD is a chemical procedure for determining the uptake rate of dissolved oxygen by the biological organisms in a body of water.
It is not a precise quantitative test, although it is widely used as an indication of the quality of water.
Moderately polluted rivers may have a BOD value in the range of 2 to 8 mg/L.
Municipal sewage that is efficiently treated by a three-stage process would have a value of about 20 mg/L or less. Untreated sewage varies, but averages around 600 mg/L in Europe.
The following notes will help you to understand more abot BOD:
Microorganisms such as bacteria are responsible for decomposing organic waste. When organic matter such as dead plants, leaves, manure, sewage, or even food waste is present in a water supply, the bacteria will begin the process of breaking down this waste. When this happens, much of the available dissolved oxygen is consumed by aerobic bacteria, robbing other aquatic organisms of the oxygen they need to live.
Biological Oxygen Demand (BOD) is a measure of the oxygen used by microorganisms to decompose this waste. If there is a large quantity of organic waste in the water supply, there will also be a lot of bacteria present working to decompose this waste. In this case, the demand for oxygen will be high (due to all the bacteria) so the BOD level will be high. As the waste is consumed or dispersed through the water, BOD levels will begin to decline.
Nitrates and phosphates in a body of water can contribute to high BOD levels. Nitrates and phosphates are plant nutrients (maybe from organic fertilisers) and can cause plant life and algae to grow quickly. When plants grow quickly, they also die quickly. This contributes to the organic waste in the water, which is then decomposed by bacteria. This results in a high BOD level.
The temperature of the water can also contribute to high BOD levels. For example, warmer water usually will have a higher BOD level than colder water. As water temperature increases, the rate of photosynthesis by algae and other plant life in the water also increases. When this happens, plants grow faster and also die faster. When the plants die, they fall to the bottom where they are decomposed by bacteria. The bacteria require oxygen for this process so the BOD is high at this location. Therefore, increased water temperatures will speed up bacterial decomposition and result in higher BOD levels.
When BOD levels are high, dissolved oxygen (DO) levels decrease because the oxygen that is available in the water is being consumed by the bacteria. Since less dissolved oxygen is available in the water, fish and other aquatic organisms may not survive.
Test Procedure:
The BOD test takes 5 days to complete and is performed using a dissolved oxygen test kit.
The BOD level is determined by comparing the DO level of a water sample taken immediately with the DO level of a water sample that has been incubated in a dark location for 5 days.
The difference between the two DO levels represents the amount of oxygen required for the decomposition of any organic material in the sample and is a good approximation of the BOD level.
1.Take 2 samples of water
2.Record the DO level (ppm) of one immediately using the method described in the dissolved oxygen test.
3.Place the second water sample in an incubator in complete darkness at 20 °C for 5 days. If you don't have an incubator, wrap the water sample bottle in aluminum foil or black electrical tape and store in a dark place at room temperature (20 °C or 68 °F).
4. After 5 days, take another dissolved oxygen reading (ppm) using the dissolved oxygen test kit.
5. Subtract the Day 5 reading from the Day 1 reading to determine the BOD level.
2.Record the DO level (ppm) of one immediately using the method described in the dissolved oxygen test.
3.Place the second water sample in an incubator in complete darkness at 20 °C for 5 days. If you don't have an incubator, wrap the water sample bottle in aluminum foil or black electrical tape and store in a dark place at room temperature (20 °C or 68 °F).
4. After 5 days, take another dissolved oxygen reading (ppm) using the dissolved oxygen test kit.
5. Subtract the Day 5 reading from the Day 1 reading to determine the BOD level.
6.Record your final BOD result in ppm.
RESULT:
BOD Level(in ppm) Water Quality
1 - 2 Very Good:There will not be much organic waste present in the water supply. 3 - 5 Fair: Moderately Clean
6 - 9 Poor: Somewhat PollutedUsually indicates organic matter is present and
bacteria are decomposing this waste.
100 or greater Very Poor: Very PollutedContains organic waste.
NOTE: Generally, when BOD levels are high, there is a decline in DO levels. This is because the demand for oxygen by the bacteria is high and they are taking that oxygen from the oxygen dissolved in the water. If there is no organic waste present in the water, there won't be as many bacteria present to decompose it and thus the BOD will tend to be lower and the DO level will tend to be higher.
..As for our experiment in our Bio Lab (Malaysian version), we are using methylene blue solution (which is blue in colour ) and will DECOLORIZE faster if there is less dissolved oxygen in the water sample…Vice versa……The more polluted the water sample is, the faster the methylene blue solution to decolorise ..
Notes are extracted..TQ
http://www.ciese.org/curriculum/dipproj2/en/fieldbook/bod.shtml
Gills: Gaseous Respiration in Fish
In respond to Question 34 SPM 2009 paper 1: about gills of a fish.
-Just like you and me fish need a constant supply oxygen in the form of oxygen in order to run their metabolism.
-Without oxygen they can't turn their food into energy or make any new fish body. All the free oxygen on this planet,was, or is being, released into the air by plants, the atmosphere at the moment is about 21% O2.
-However oxygen will dissolve in water,
-Fish could of course breathe air like Seals and Whales, and some do, but if they wish to stay safe under the water for longer periods of time it would be much easier if they could get the oxygen they need from the water, and this is exactly what they do. In fact they were doing this long before any vertebrate animals learned how to breath the air.
-So fish live in the water and they breathe the water, to do this they have special organs called gills.
Extracted notes from sources...TQ
http://www.earthlife.net/fish/gills.html
-Just like you and me fish need a constant supply oxygen in the form of oxygen in order to run their metabolism.
-Without oxygen they can't turn their food into energy or make any new fish body. All the free oxygen on this planet,was, or is being, released into the air by plants, the atmosphere at the moment is about 21% O2.
-However oxygen will dissolve in water,
-Fish could of course breathe air like Seals and Whales, and some do, but if they wish to stay safe under the water for longer periods of time it would be much easier if they could get the oxygen they need from the water, and this is exactly what they do. In fact they were doing this long before any vertebrate animals learned how to breath the air.
-So fish live in the water and they breathe the water, to do this they have special organs called gills.
-Gills are wonderfully well designed, and they have to be because although the water does hold some oxygen it never holds any where near as much as the air, and to make things more difficult the amount of oxygen a body of water can hold decreases the warmer it becomes, and also, salt water holds less oxygen than fresh water.
-What this means to the fish is that their gills need to be a lot more efficient at extracting O2 from the water than our lungs need to be at extracting it from the air.
-Fish solve the problems of extracting the O2 they need from the water they live in a variety of ways.
-Firstly they have different life styles, obviously a fish that spends most of its life resting on the bottom of the ocean waiting for its dinner to swim by needs less O2 than a fish which actively chases smaller fish for its dinner.
-However most of the problem is solved in the design of the gills.
-A fish's gills are situated one set on either side of the body and near the back of the head
-In fish there is a bony plate protecting the gills, this is called the operculum, and it is hinged and has muscles attached to it so it can be regularly opened and closed.
-This ability to have water continually passing over the gills is one of the major factors making gills more efficient than lungs.
-With lungs the air comes in, fills the space, and then has to be expelled before any more O2 rich air can be brought in. With gills there is no time wasted getting rid of the old air/water and no energy wasted reversing the direction of the flow..
-In sharks and rays the number of gills is usually 5, but there are some species with 6 or 7 sets, in fish the number of gills is 4 on either side of the body.
-Each gill is supported by a gill arch and protected by gill rakers.
-Each gill arch supports one set of paired gill filaments.
-The gill rakers help make sure that no extraneous material gets into the gill filaments to clog them up.
-Each paired gill filament in turn supports numerous lamellae (sing. lamella), extending out from both sides of the filament body.
It's here in the lamellae that the uptake of O2 actually occurs.
-The lamellae are very fine structures, however there exact dimensions depend on the normal activity levels of the fish in question.
-The more active the fish the thinner they are and the less distance there is between them. Also the absolute thickness of the individual lamellae walls varies, this is important in considering to facility with which O2can diffuse from the water to the fish's blood, the thinner the membrane the more quickly. and easily the O2 can pass across it.
Thus in sluggish fish like the American Brown Bullhead (Amerius nebulosus) the lamellae are 25 µ thick, 45 µ apart and the lamellae walls are 10 µ thick giving you 14 lamellae per mm, whereas in a highly active fish such as the Atlantic Herring (Clupea harengus) the lamellae are 7µ thick, 20 µ apart and the lamellae walls are >1µ in width, giving you 32 lamellae per mm.
-The presence of all these lamellae greatly increases the surface area of the gills, meaning that a large amount of water is available for gaseous exchange at any particular moment of time.
-The Lamellae are basically collections of blood vessels sandwiched between two sets of membranes. The membranes keep the blood and the water separate whilst allowing the dissolved gases, O2 and CO2, to diffuse naturally from one liquid to the other, depending on which has the greater concentration of either gas.
-The laws of physics compel gases to seek equilibrium, if you have different concentrations of a particular gas on either side of a permeable membrane (i.e. a membrane that very small gas molecules can pass through, but not larger organic molecules) then the gas will move from the side with the greater concentration to the other without you having to do anything.
-To ensure a continuous gradient of gaseous difference between its blood and the water flowing past its gills fish use a counter-current system.
-This means that the blood flows along the vessels in the lamellae in the opposite direction to which the water is passing on the outside of the lamellae.
-Fish can breathe the water by swimming forwards and letting some of the passing water flow in through the mouth, across the gills, and then out.
-They can control the amount of blood flowing through their gills, increasing the amount of oxygen they take from the water if they being more active. When they are moving slowly, or resting in the water fish can breathe the water by synchronously expanding and contracting the buccal cavity (the mouth and throat), and the opercular cavity, which is the space behind the operculum where the gills are. In doing this they can pump a continuous stream of water across their gills.
-Most fish can also absorb some O2 through their skin, and while they are in their larval form this is often the main source of respiration.
Extracted notes from sources...TQ
http://www.earthlife.net/fish/gills.html
Wednesday, December 9, 2009
Digestive system-Paper 1
When you talk about digestive system of man you must be aware of the part which is exactly contains beneficial bacteria!!!...I repeat: beneficial bacteria!!!
Bacteria in your colon are referred to by many different names - probiotics, good or bad bacteria, beneficial bacteria, micro flora, proflora, friendly flora, and unfriendly bacteria.
It refer to all the bacteria that exist in the small intestine and your colon.
Your colon has both good and bad bacteria.
The good bacteria maintain the health of your colon by keeping the bad bacteria from multiplying and reducing constipation.
Most people have bad bacteria as the dominant condition in their colon.
You can see this by the illnesses that exist throughout the world.
Most people later in their life suffer from diseases that resulted from colon neglect and abuse.
Bad bacteria multiples when you,
* Consume poisons such as pollution, pesticides, food additives such as preservatives, coloring, so on.
* Drink alcohol
* Eat processed foods
* Have excess anxiety
* Lack fiber in your diet
* Use drugs and medication
Good bacteria in your colon consists of hundred of species of bacteria.
The good bacteria are most active in a pH of 5.9 to 6.9- an acidic environment. This makes for a healthy colon.
Your colon serves as a home for the good bacteria, which ferment specific carbohydrates, which in turn keep your colon environment slightly acidic.
The acid environment favors the good bacteria and keeps the bad bacteria and pathogens from multiplying.
The bad bacteria create an alkaline environment and are most active in a pH of 7.1 to 7.9
Again, the good bacteria creates an acidic environment and are most active in a pH of 5.9 to 6.9
Acidophilus and Bifidus are the main good bacteria that exist in your colon.
The ascending colon, on the right side of your abdomen area, has the most bacteria.
The quantity of bacteria becomes less in the transverse colon and lesser in the descending colon. Eventually, little bacteria is found in the sigmoid and rectum.
When good beneficial bacteria is dominant, in your colon, it prevents the spread of disease from various organisms - parasites, bacteria, viruses, fungi.
The good bacteria keep these organisms in the minority, thus preventing them from multiplying, getting into the blood, and into the different body organs.
They do this by their antibiotic like secretions, lactic acid production, and other secretions, which keep their environment acidic.
The good bacteria live and thrive on carbohydrates. When your body has good digestion and little carbohydrates reach your colon, the good bacteria population decreases and the bad bacteria become dominant.
In a healthy colon, there are literally billions of beneficial or "friendly" bacteria.
Under favorable conditions, they multiply at a fast enough rate to keep pace with the large numbers that are lost during elimination.
Bacteria is also referred to as micro-organisms.
When they are located in the intestinal tract, they are referred to as "intestinal flora," "micro-flora", "good bacteria", "friendly/beneficial bacteria" or sometimes just "flora."
These friendly bacteria synthesize many important vitamins in the digestive tract including Vitamin K and some of the B vitamins.
A very important function they perform is helping the colon maintain a proper pH or acid-base balance.
It is necessary for the pH to stay in the correct range in order for other health supporting bacteria to exist. It is also important to keep levels of antagonistic micro-organisms under control.
***Colon is an important organ in the digestive system.
15 things that researchers have said cause colon cancer or contribute to its development.
1. Age
Age is the number one risk factor for colon cancer. Does that mean that age causes colon cancer? Not directly. It's just that by age age 50, one in four people has polyps.
2. Alcohol
Research has indicated that alcohol increases colorectal cancer risk.
3. Diabetes
In general, diabetics are up to 40% more likely to develop colon cancer than people who don't have diabetes.
4. Diet
Diets high in fat and cholesterol (especially from animal sources) have been found to cause colon cancer. Low-fiber diets have also been associated with increased risk, but the research isn't as clear
5. Environment
Research has shown that environment can play a big part in colon cancer development. Where you live, who's around you, your occupation, and even when you work may all influence your risk of developing colon cancer.
6. Ethnicity, Race, and Social Status
Does colorectal cancer afflict everyone equally or are some groups of people more likely to be diagnosed than others? The reasons are varied, but some groups get colorectal cancer more often than others. Ethnicity, race, and social status all play a part.
7. Family Medical History
Most colon cancer occurs in people with no family history of the disease. But, colon cancer can run in the family. Whether you're at increased risk depends on which family member was diagnosed and at what age.
8. Gender
You may have heard that men are more likely to get colorectal cancer than women. You may have heard it the other way around, too. Both statements can be true depending on the context.
9. Genetics
Researchers estimate that about 25% of colon cancer cases have some sort of genetic link.
10. Inflammatory Bowel Disease (IBD)
Inflammatory bowel disease, often characterized by conditions such as ulcerative colitis and Chron's disease, increases the risk of developing colorectal cancer. In general, the longer a person has had inflammatory bowel disease, the greater his or her chance of developing colorectal cancer.
11. Lack of Exercise
There's no denying that exercise is good for you. Research has shown that a sedentary lifestyle contributes to colon cancer development.
12. Obesity
Nobody likes to have the word obese thrown at them. But, obesity is a medical term that indicates someone exceeds their recommended weight, one step beyond simply being overweight. And the answer to the question is yes, obesity does increase colon cancer risk.
13. Personal Medical History
Your personal medical history can significantly impact your chances of developing colorectal cancer. A medical history that includes polyps, bowel inflammation, or certain cancers is particularly relevant.
14. Polyps
Virtually all colon cancer develops from adenomatous polyps in the colon, generally referred to simply as colon polyps. A personal or family history of polyps puts you at higher risk for colon cancer.
15. Smoking
Long-term cigarette smoking causes colon cancer for two main reasons. First, inhaled or swallowed tobacco smoke transports carcinogens to the colon. Second, tobacco use appears to increase polyp size.
**Notes are extracted.
Bacteria in your colon are referred to by many different names - probiotics, good or bad bacteria, beneficial bacteria, micro flora, proflora, friendly flora, and unfriendly bacteria.
It refer to all the bacteria that exist in the small intestine and your colon.
Your colon has both good and bad bacteria.
The good bacteria maintain the health of your colon by keeping the bad bacteria from multiplying and reducing constipation.
Most people have bad bacteria as the dominant condition in their colon.
You can see this by the illnesses that exist throughout the world.
Most people later in their life suffer from diseases that resulted from colon neglect and abuse.
Bad bacteria multiples when you,
* Consume poisons such as pollution, pesticides, food additives such as preservatives, coloring, so on.
* Drink alcohol
* Eat processed foods
* Have excess anxiety
* Lack fiber in your diet
* Use drugs and medication
Good bacteria in your colon consists of hundred of species of bacteria.
The good bacteria are most active in a pH of 5.9 to 6.9- an acidic environment. This makes for a healthy colon.
Your colon serves as a home for the good bacteria, which ferment specific carbohydrates, which in turn keep your colon environment slightly acidic.
The acid environment favors the good bacteria and keeps the bad bacteria and pathogens from multiplying.
The bad bacteria create an alkaline environment and are most active in a pH of 7.1 to 7.9
Again, the good bacteria creates an acidic environment and are most active in a pH of 5.9 to 6.9
Acidophilus and Bifidus are the main good bacteria that exist in your colon.
The ascending colon, on the right side of your abdomen area, has the most bacteria.
The quantity of bacteria becomes less in the transverse colon and lesser in the descending colon. Eventually, little bacteria is found in the sigmoid and rectum.
When good beneficial bacteria is dominant, in your colon, it prevents the spread of disease from various organisms - parasites, bacteria, viruses, fungi.
The good bacteria keep these organisms in the minority, thus preventing them from multiplying, getting into the blood, and into the different body organs.
They do this by their antibiotic like secretions, lactic acid production, and other secretions, which keep their environment acidic.
The good bacteria live and thrive on carbohydrates. When your body has good digestion and little carbohydrates reach your colon, the good bacteria population decreases and the bad bacteria become dominant.
In a healthy colon, there are literally billions of beneficial or "friendly" bacteria.
Under favorable conditions, they multiply at a fast enough rate to keep pace with the large numbers that are lost during elimination.
Bacteria is also referred to as micro-organisms.
When they are located in the intestinal tract, they are referred to as "intestinal flora," "micro-flora", "good bacteria", "friendly/beneficial bacteria" or sometimes just "flora."
These friendly bacteria synthesize many important vitamins in the digestive tract including Vitamin K and some of the B vitamins.
A very important function they perform is helping the colon maintain a proper pH or acid-base balance.
It is necessary for the pH to stay in the correct range in order for other health supporting bacteria to exist. It is also important to keep levels of antagonistic micro-organisms under control.
***Colon is an important organ in the digestive system.
15 things that researchers have said cause colon cancer or contribute to its development.
1. Age
Age is the number one risk factor for colon cancer. Does that mean that age causes colon cancer? Not directly. It's just that by age age 50, one in four people has polyps.
2. Alcohol
Research has indicated that alcohol increases colorectal cancer risk.
3. Diabetes
In general, diabetics are up to 40% more likely to develop colon cancer than people who don't have diabetes.
4. Diet
Diets high in fat and cholesterol (especially from animal sources) have been found to cause colon cancer. Low-fiber diets have also been associated with increased risk, but the research isn't as clear
5. Environment
Research has shown that environment can play a big part in colon cancer development. Where you live, who's around you, your occupation, and even when you work may all influence your risk of developing colon cancer.
6. Ethnicity, Race, and Social Status
Does colorectal cancer afflict everyone equally or are some groups of people more likely to be diagnosed than others? The reasons are varied, but some groups get colorectal cancer more often than others. Ethnicity, race, and social status all play a part.
7. Family Medical History
Most colon cancer occurs in people with no family history of the disease. But, colon cancer can run in the family. Whether you're at increased risk depends on which family member was diagnosed and at what age.
8. Gender
You may have heard that men are more likely to get colorectal cancer than women. You may have heard it the other way around, too. Both statements can be true depending on the context.
9. Genetics
Researchers estimate that about 25% of colon cancer cases have some sort of genetic link.
10. Inflammatory Bowel Disease (IBD)
Inflammatory bowel disease, often characterized by conditions such as ulcerative colitis and Chron's disease, increases the risk of developing colorectal cancer. In general, the longer a person has had inflammatory bowel disease, the greater his or her chance of developing colorectal cancer.
11. Lack of Exercise
There's no denying that exercise is good for you. Research has shown that a sedentary lifestyle contributes to colon cancer development.
12. Obesity
Nobody likes to have the word obese thrown at them. But, obesity is a medical term that indicates someone exceeds their recommended weight, one step beyond simply being overweight. And the answer to the question is yes, obesity does increase colon cancer risk.
13. Personal Medical History
Your personal medical history can significantly impact your chances of developing colorectal cancer. A medical history that includes polyps, bowel inflammation, or certain cancers is particularly relevant.
14. Polyps
Virtually all colon cancer develops from adenomatous polyps in the colon, generally referred to simply as colon polyps. A personal or family history of polyps puts you at higher risk for colon cancer.
15. Smoking
Long-term cigarette smoking causes colon cancer for two main reasons. First, inhaled or swallowed tobacco smoke transports carcinogens to the colon. Second, tobacco use appears to increase polyp size.
**Notes are extracted.
Monday, December 7, 2009
Hydrolysis Vs Condensation
Many students are still confused over these two processes..and this is partly the reason why there are questions regarding these two processes. And in paper 1 2009 recently, Qs 9 and 10 are related...
What is Hydrolysis?
-Hydrolysis is a chemical reaction during which one or more water molecules are split into hydrogen and hydroxide ions in the process of a chemical mechanism.
- It is the type of reaction that is used to break down certain polymers,
-Hydrolysis is a chemical process in which a molecule is cleaved into two parts by the addition of a molecule of water
-Hydrolysis is the chemical reaction that involves the breaking up of large molecules by adding water to them ( hydro=water, lysis=break )
Examples:
The breakdown of triglyceride to form glycerol and fatty acids.
The breakdown of polypeptides to form dipeptides
The breakdown of starch to form maltose
What is Condensation?
-A condensation reaction takes place releasing water. This process requires energy--
-Monosaccharides combine to form disaccharides through Condensation.
Please search for more examples which involves polysaccharides, polypeptides and triglycerides...
What is Hydrolysis?
-Hydrolysis is a chemical reaction during which one or more water molecules are split into hydrogen and hydroxide ions in the process of a chemical mechanism.
- It is the type of reaction that is used to break down certain polymers,
-Hydrolysis is a chemical process in which a molecule is cleaved into two parts by the addition of a molecule of water
-Hydrolysis is the chemical reaction that involves the breaking up of large molecules by adding water to them ( hydro=water, lysis=break )
Examples:
The breakdown of triglyceride to form glycerol and fatty acids.
The breakdown of polypeptides to form dipeptides
The breakdown of starch to form maltose
What is Condensation?
-A condensation reaction takes place releasing water. This process requires energy--
-Monosaccharides combine to form disaccharides through Condensation.
Please search for more examples which involves polysaccharides, polypeptides and triglycerides...
Saturday, December 5, 2009
Down Syndrome
What is Down Syndrome?
-Down syndrome (DS), also called Trisomy 21, is a condition in which extra genetic material causes delays in the way a child develops, both mentally and physically. It affects about 1 in every 800 babies.
-The physical features and medical problems associated with Down syndrome can vary widely from child to child. While some kids with DS need a lot of medical attention, others lead healthy lives.
-Though Down syndrome can't be prevented, it can be detected before a child is born.
-The health problems that can go along with DS can be treated, and there are many resources within communities to help kids and their families who are living with the condition.
What Causes It?
-Normally, at the time of conception a baby inherits genetic information from its parents in the form of 46 chromosomes: 23 from the mother and 23 from the father.
-In most cases of Down syndrome, a child gets an extra chromosome 21 — for a total of 47 chromosomes instead of 46.
-It's this extra genetic material that causes the physical features and developmental delays associated with DS.
-Although no one knows for sure why DS occurs and there's no way to prevent the chromosomal error that causes it, scientists do know that women age 35 and older have a significantly higher risk of having a child with the condition.
-At age 30, for example, a woman has about a 1 in 900 chance of conceiving a child with DS. Those odds increase to about 1 in 350 by age 35. By 40 the risk rises to about 1 in 100
How Down Syndrome Affects Kids
Kids with Down syndrome tend to share certain physical features such as :(SPM QS 2009)
i. a flat facial profile,
ii.an upward slant to the eyes,
iii.small ears, and
iv.a protruding tongue.
Low muscle tone (called hypotonia) is also characteristic of children with DS, and babies in particular may seem especially "floppy." Though this can and often does improve over time, most children with DS typically reach developmental milestones — like sitting up, crawling, and walking — later than other kids.
At birth, kids with DS are usually of average size, but they tend to grow at a slower rate and remain smaller than their peers. For infants, low muscle tone may contribute to sucking and feeding problems, as well as constipation and other digestive issues. Toddlers and older kids may have delays in speech and self-care skills like feeding, dressing, and toilet teaching.
Down syndrome affects kids' ability to learn in different ways, but most have mild to moderate intellectual impairment. Kids with DS can and do learn, and are capable of developing skills throughout their lives. They simply reach goals at a different pace — which is why it's important not to compare a child with DS against typically developing siblings or even other children with the condition.
Kids with DS have a wide range of abilities, and there's no way to tell at birth what they will be capable of as they grow up.
**Photos and articles r extracted.
-Down syndrome (DS), also called Trisomy 21, is a condition in which extra genetic material causes delays in the way a child develops, both mentally and physically. It affects about 1 in every 800 babies.
-The physical features and medical problems associated with Down syndrome can vary widely from child to child. While some kids with DS need a lot of medical attention, others lead healthy lives.
-Though Down syndrome can't be prevented, it can be detected before a child is born.
-The health problems that can go along with DS can be treated, and there are many resources within communities to help kids and their families who are living with the condition.
What Causes It?
-Normally, at the time of conception a baby inherits genetic information from its parents in the form of 46 chromosomes: 23 from the mother and 23 from the father.
-In most cases of Down syndrome, a child gets an extra chromosome 21 — for a total of 47 chromosomes instead of 46.
-It's this extra genetic material that causes the physical features and developmental delays associated with DS.
-Although no one knows for sure why DS occurs and there's no way to prevent the chromosomal error that causes it, scientists do know that women age 35 and older have a significantly higher risk of having a child with the condition.
-At age 30, for example, a woman has about a 1 in 900 chance of conceiving a child with DS. Those odds increase to about 1 in 350 by age 35. By 40 the risk rises to about 1 in 100
How Down Syndrome Affects Kids
Kids with Down syndrome tend to share certain physical features such as :(SPM QS 2009)
i. a flat facial profile,
ii.an upward slant to the eyes,
iii.small ears, and
iv.a protruding tongue.
Low muscle tone (called hypotonia) is also characteristic of children with DS, and babies in particular may seem especially "floppy." Though this can and often does improve over time, most children with DS typically reach developmental milestones — like sitting up, crawling, and walking — later than other kids.
At birth, kids with DS are usually of average size, but they tend to grow at a slower rate and remain smaller than their peers. For infants, low muscle tone may contribute to sucking and feeding problems, as well as constipation and other digestive issues. Toddlers and older kids may have delays in speech and self-care skills like feeding, dressing, and toilet teaching.
Down syndrome affects kids' ability to learn in different ways, but most have mild to moderate intellectual impairment. Kids with DS can and do learn, and are capable of developing skills throughout their lives. They simply reach goals at a different pace — which is why it's important not to compare a child with DS against typically developing siblings or even other children with the condition.
Kids with DS have a wide range of abilities, and there's no way to tell at birth what they will be capable of as they grow up.
**Photos and articles r extracted.
Sample Qs-Placenta
This is SBP Paper 2 Trial SPM 2009...It is about placenta..and in real SPM Biology, there is one question about placenta in paper 2 too...
Diagram 5 shows prenatal development of a human embryo.
(a)(i)Name two materials that pass via R(placenta) from mother to the foetus.
(ii)Name two materials in blood of mother that are partially prevented by R (placenta) from entering the blood of foetus.
(b)Explain how the structure of R enable a rapid exchange of materials to take place [2m]
(c)State two differences between the content of R and foetal blood.[2m]
(d) R regress and cause miscarriage.
Explain the above statement.[2m]
(e) Explain why colostrums valuable to the baby immediately after birth.[2m]
Suggested Answer:
(a)(i) Able to name the materials that can pass via placenta
Sample answer:
water / amino acid / glucose /nutrients / oxygen /antibodies
(ii) Able to name the materials that partially prevented by placenta
Sample answer :
Drugs / alcohol / caffeine / nicotine / HIV / rubella virus
(b)Able to explain the adaptation of the structure R
Sample answer :
F1 : placenta has a large surface area to volume ratio.
P1 : to increase exchange rate
F2 : material and embryonic bloods are brought into close contact.
P2 : diffusion can take place efficiently
F3 : separated only by a thin membrane
P3 : diffusion can take place efficiently
Any F with correspond P
(c) R Foetal blood
Oxygen high low
nutrient high low
Carbon dioxide low high
Waste / example Low high
(d)Sample answer :
F : placenta acts as an endocrine gland // secreting oestrogen/progesterone.
P : (these hormone) help to maintain a thickened / blood enriched endometrium throughout the pregnancy.
(e) Able to explain the importance of colostrums to newborn baby.
Sample answer :
F : colostrums contain antibodies
P : to help infant / baby survive from pathogens .
...................................and the immunity foetus get from mother is passive natural!
Diagram 5 shows prenatal development of a human embryo.
(a)(i)Name two materials that pass via R(placenta) from mother to the foetus.
(ii)Name two materials in blood of mother that are partially prevented by R (placenta) from entering the blood of foetus.
(b)Explain how the structure of R enable a rapid exchange of materials to take place [2m]
(c)State two differences between the content of R and foetal blood.[2m]
(d) R regress and cause miscarriage.
Explain the above statement.[2m]
(e) Explain why colostrums valuable to the baby immediately after birth.[2m]
Suggested Answer:
(a)(i) Able to name the materials that can pass via placenta
Sample answer:
water / amino acid / glucose /nutrients / oxygen /antibodies
(ii) Able to name the materials that partially prevented by placenta
Sample answer :
Drugs / alcohol / caffeine / nicotine / HIV / rubella virus
(b)Able to explain the adaptation of the structure R
Sample answer :
F1 : placenta has a large surface area to volume ratio.
P1 : to increase exchange rate
F2 : material and embryonic bloods are brought into close contact.
P2 : diffusion can take place efficiently
F3 : separated only by a thin membrane
P3 : diffusion can take place efficiently
Any F with correspond P
(c) R Foetal blood
Oxygen high low
nutrient high low
Carbon dioxide low high
Waste / example Low high
(d)Sample answer :
F : placenta acts as an endocrine gland // secreting oestrogen/progesterone.
P : (these hormone) help to maintain a thickened / blood enriched endometrium throughout the pregnancy.
(e) Able to explain the importance of colostrums to newborn baby.
Sample answer :
F : colostrums contain antibodies
P : to help infant / baby survive from pathogens .
...................................and the immunity foetus get from mother is passive natural!
Thursday, December 3, 2009
One episode has ended...another's coming..
..Thanks to God almighty, Bio papers finally were done...
..Some did it well, some??..as usual: sighing and regretting...for not memorising certain facts of the chapters...
I found the questions were quite straight forward...(Paper 2)...and of course paper 3 was simple...The questions asked were within the syllabus, no extra ordinary...But if you didnt remember facts, then it ws difficult...And if you rely so much on spotted Qs, then you could be dissapointed...
I have my job done,(at least for 2009)..and intend to continue another episode...with my form five-to-be girls (2010)...After Valiants, what will be their batch's name?
..And I will continue publishing the posts, adding more notes and tips according to chapters...and for a time being, to all the form fours (taking biology), the whole of Malaysia, if you happen to bump into my blogspot, be free to browse tru my notes...and i really hope all of you will use it as a reference!..and dont forget to be my followers and leave comments....
...Some of the Diagrams asked in Paper 2...
..Some did it well, some??..as usual: sighing and regretting...for not memorising certain facts of the chapters...
I found the questions were quite straight forward...(Paper 2)...and of course paper 3 was simple...The questions asked were within the syllabus, no extra ordinary...But if you didnt remember facts, then it ws difficult...And if you rely so much on spotted Qs, then you could be dissapointed...
I have my job done,(at least for 2009)..and intend to continue another episode...with my form five-to-be girls (2010)...After Valiants, what will be their batch's name?
..And I will continue publishing the posts, adding more notes and tips according to chapters...and for a time being, to all the form fours (taking biology), the whole of Malaysia, if you happen to bump into my blogspot, be free to browse tru my notes...and i really hope all of you will use it as a reference!..and dont forget to be my followers and leave comments....
...Some of the Diagrams asked in Paper 2...
Wednesday, December 2, 2009
Bio SPM 2009-REAL
Paper 2:
STRUCTURE:
Q1: plant cell- Golgi apparatus, chloroplast, hypertonic solution [FORM 4]
Qs2:spermatogenesis, Down's syndrome, explain the genetic disorder [FORM 5]
Qs3:stems in different habitat, phloem function, differences between xylem and phloem, importance of mitosis, adaptations of plants is soft muddy soil [ FORM 4]
Qs4: human respiratory system- intercostal muscles, diaphragm, gas exchnage, alveoli adaptation.[FORM 4]
Q5: placenta, umbilical cord, blood compositions in blood vessels of umbilical cord, immunity in foetus, why foetus has separate blood circulatory system frm his mother.[FORM 5]
ESSAY:
Q6:mendel's Law II, haemophilia schematic Diagram [FORM 5]
Q7:Interaction (Rafflesia ), prey-predator biology control, Nitrogen Cycle [FORM 4]
Q8: Transpiration, movement of water molecules in a plant. [FORM 5]
Q9:lipid assimilation, relationship between eating habits and physical condition of the given diagrams.[ FORM 4]
PAPER 3
Q1: The effect of light intensity on the rate of photosynthesis.
Q2: The effect of temperature on the rate of enzyme reaction.
STRUCTURE:
Q1: plant cell- Golgi apparatus, chloroplast, hypertonic solution [FORM 4]
Qs2:spermatogenesis, Down's syndrome, explain the genetic disorder [FORM 5]
Qs3:stems in different habitat, phloem function, differences between xylem and phloem, importance of mitosis, adaptations of plants is soft muddy soil [ FORM 4]
Qs4: human respiratory system- intercostal muscles, diaphragm, gas exchnage, alveoli adaptation.[FORM 4]
Q5: placenta, umbilical cord, blood compositions in blood vessels of umbilical cord, immunity in foetus, why foetus has separate blood circulatory system frm his mother.[FORM 5]
ESSAY:
Q6:mendel's Law II, haemophilia schematic Diagram [FORM 5]
Q7:Interaction (Rafflesia ), prey-predator biology control, Nitrogen Cycle [FORM 4]
Q8: Transpiration, movement of water molecules in a plant. [FORM 5]
Q9:lipid assimilation, relationship between eating habits and physical condition of the given diagrams.[ FORM 4]
PAPER 3
Q1: The effect of light intensity on the rate of photosynthesis.
Q2: The effect of temperature on the rate of enzyme reaction.
Thursday, November 26, 2009
BIO...here I come!
By now everybody should have confident to sit for Bio papers...With all the given tips by your teachers...for two years!...and I'm hoping I might do a bit of contribution to you too.....
Well...I got mesages from all around the country...I've gone tru Andrew Choo web (bcoz somebody recommended it to me...)..I feel it is safer for you to know the contents of Bio as a whole and able to relate all the chapters well when you answer the questions....
..Among last minute advice include:
1. Read the question well
2. Underline the requirement of the questions
3.Look at the marks allocated.
4.Prepare mind map/flow chart as a draft before start writing.
5. Start like a story teller....
6.End up your essay properly.
7.Write freely...step by step..
8.Dont worry about the language..insert BM terms if you suddenly get stuck with english words.
9.Dont panic..take a deep breath if suddenly you get stuck...slowly recall the facts required...
10...have faith and confidence ...in yourself
...and here are some of the topics being mentioned by my networking friends...
Paper 2:
* Plant cell, organelles, hypotonic, isotonic, hypertonic...
*Enzymes
* meiosis,mitosis, cloning, genetic engineering
*respiration anaerobic/aerobic,
*nutrition:ruminant/rodent
*assimilation
*homeostasis-osmoregulation
*menstrual cycle-hormones, negative feedback mechanism, spermatogenesis/oogenesis, placenta
*Double fertilisation
*Mendel's Law 2
*Variation- mutation
*Reflex arc - synapse
Paper 3:
Question 1:
1. Transpiration/
2. Photosynthesis
Question 2:
....Many possibilities...But one thing for sure, they are any of these:
Design and conduct experiments to study factors affecting the rate of transpiration:
a) air movement,
b) temperature,
c) light intensity,
d) relative humidity
Design an experiment to show the effect of different quantities of water intake on urine output.
Conduct experiments to study the effects of
i. pH
ii. temperature on the activities of amylase and pepsin.
Discuss the effects of enzyme substrate concentration on enzyme activity.
Conduct an activity to determine the energy value in food samples.
Conduct an experiment to determine the vitamin C content in various fruit juices
Design experiments to study the digestion of starch and proteins
Design an experiment to study the effects of macronutrient deficiency in plants,
Design an experiment to investigate the effect of light intensity on the rate of photosynthesis,
the effects of :
i. light intensity
ii. temperature and
iii. concentration of carbon dioxide
on rate of photosynthesis.
Carry out an experiment to investigate anaerobic respiration in yeast.
The effect of temperature on the rate of anaerobic respiration in yeast
Conduct an experiment to investigate the differences between inhale and exhale air
Discuss and conduct an experiment to show the effects of cigarette smoke on white cotton wool and draw an anology between the lung and the white cotton wool.
Conduct an experiment to study the intraspecific competition and interspecific competiton of plants, e.g. maize and rice
Conduct a field study or use an appropriate anology to:
i. estimate the population size of animals such as garden snail and wood lice,
ii. investigate the distribution of plants using the quadrat sampling technique,
Plan and conduct an experiment to study the relationship of population distribution of an organism with changes in any one of the abiotic factors such as pH, temperature, light intensity and humidity.
Suggested organisms:
Pleurococcus, Lemna
Conduct an experiment to study the effects of temperature, pH, light and nutrients on the activity of microorganisms e.g. Bacillus subtilis or yeast
Conduct an activity to analyse data on air pollution index of some cities within and outside the country,and make and inference on the sources of pollution.
Conduct an activity to analyse data on water pollution , such as Oxygen Demand (BOD) value and content to heavy metals in some rivers,and make an inference on the sources of pollution.
Correlate different sizes of cubes to total surface area / volume (TSA/V) ratio,
Discuss how the (TSA/V) ratio affects the movement of solutes to the interior of cubes,
Design and conduct experiments to study factors affecting the rate of transpiration, i.e.:
i. air movement,
ii. temperature,
iii. light intensity,
iv. relative humidity.
Design an experiment to show the effect of different quantities of water intake on urine output.
Conduct an activity to study the growth of a plant, e.g. onion, maize, or balsam.
Conduct an activity using coloured buttons/beans to illustrate Mendel’s First Law.
Conduct an activity to investigate variation in humans and present the data graphically
...ALL THE BEST...
Well...I got mesages from all around the country...I've gone tru Andrew Choo web (bcoz somebody recommended it to me...)..I feel it is safer for you to know the contents of Bio as a whole and able to relate all the chapters well when you answer the questions....
..Among last minute advice include:
1. Read the question well
2. Underline the requirement of the questions
3.Look at the marks allocated.
4.Prepare mind map/flow chart as a draft before start writing.
5. Start like a story teller....
6.End up your essay properly.
7.Write freely...step by step..
8.Dont worry about the language..insert BM terms if you suddenly get stuck with english words.
9.Dont panic..take a deep breath if suddenly you get stuck...slowly recall the facts required...
10...have faith and confidence ...in yourself
...and here are some of the topics being mentioned by my networking friends...
Paper 2:
* Plant cell, organelles, hypotonic, isotonic, hypertonic...
*Enzymes
* meiosis,mitosis, cloning, genetic engineering
*respiration anaerobic/aerobic,
*nutrition:ruminant/rodent
*assimilation
*homeostasis-osmoregulation
*menstrual cycle-hormones, negative feedback mechanism, spermatogenesis/oogenesis, placenta
*Double fertilisation
*Mendel's Law 2
*Variation- mutation
*Reflex arc - synapse
Paper 3:
Question 1:
1. Transpiration/
2. Photosynthesis
Question 2:
....Many possibilities...But one thing for sure, they are any of these:
Design and conduct experiments to study factors affecting the rate of transpiration:
a) air movement,
b) temperature,
c) light intensity,
d) relative humidity
Design an experiment to show the effect of different quantities of water intake on urine output.
Conduct experiments to study the effects of
i. pH
ii. temperature on the activities of amylase and pepsin.
Discuss the effects of enzyme substrate concentration on enzyme activity.
Conduct an activity to determine the energy value in food samples.
Conduct an experiment to determine the vitamin C content in various fruit juices
Design experiments to study the digestion of starch and proteins
Design an experiment to study the effects of macronutrient deficiency in plants,
Design an experiment to investigate the effect of light intensity on the rate of photosynthesis,
the effects of :
i. light intensity
ii. temperature and
iii. concentration of carbon dioxide
on rate of photosynthesis.
Carry out an experiment to investigate anaerobic respiration in yeast.
The effect of temperature on the rate of anaerobic respiration in yeast
Conduct an experiment to investigate the differences between inhale and exhale air
Discuss and conduct an experiment to show the effects of cigarette smoke on white cotton wool and draw an anology between the lung and the white cotton wool.
Conduct an experiment to study the intraspecific competition and interspecific competiton of plants, e.g. maize and rice
Conduct a field study or use an appropriate anology to:
i. estimate the population size of animals such as garden snail and wood lice,
ii. investigate the distribution of plants using the quadrat sampling technique,
Plan and conduct an experiment to study the relationship of population distribution of an organism with changes in any one of the abiotic factors such as pH, temperature, light intensity and humidity.
Suggested organisms:
Pleurococcus, Lemna
Conduct an experiment to study the effects of temperature, pH, light and nutrients on the activity of microorganisms e.g. Bacillus subtilis or yeast
Conduct an activity to analyse data on air pollution index of some cities within and outside the country,and make and inference on the sources of pollution.
Conduct an activity to analyse data on water pollution , such as Oxygen Demand (BOD) value and content to heavy metals in some rivers,and make an inference on the sources of pollution.
Correlate different sizes of cubes to total surface area / volume (TSA/V) ratio,
Discuss how the (TSA/V) ratio affects the movement of solutes to the interior of cubes,
Design and conduct experiments to study factors affecting the rate of transpiration, i.e.:
i. air movement,
ii. temperature,
iii. light intensity,
iv. relative humidity.
Design an experiment to show the effect of different quantities of water intake on urine output.
Conduct an activity to study the growth of a plant, e.g. onion, maize, or balsam.
Conduct an activity using coloured buttons/beans to illustrate Mendel’s First Law.
Conduct an activity to investigate variation in humans and present the data graphically
...ALL THE BEST...
Sunday, November 22, 2009
Sample Qs-Genetic engineering
Question 1
(a) Explain the principle involved in genetic engineering [2 marks]
(b) Discuss the importance of genetic engineering in the medical and agricultural field. [ 4 marks] (c) Diagram shows DNA finger printing. DNA finger printing is more scientific, accurate and advanced compared to the thumbprint in criminal investigation.
Discuss the use of DNA fingerprinting in the identification of the parents of a child. [4 marks]
In some programs, genetic counselors use DNA fingerprint information to help prospective parents understand the risk of having an affected child.
In other programs, prospective parents use DNA fingerprint information in their decisions concerning affected pregnancies.
Developing cures for inherited disorders
Research programs to locate inherited disorders on the chromosomes depend on the information contained in DNA fingerprints.
By studying the DNA fingerprints of relatives who have a history of some particular disorder, or by comparing large groups of people with and without the disorder, it is possible to identify DNA patterns associated with the disease in question.
This work is a necessary first step in designing an eventual genetic cure for these disorders.
Forensic or criminal
FBI and police labs around the U.S. have begun to use DNA fingerprints to link suspects to biological evidence-blood or semen stains, hair, or items of clothing-found at the scene of a crime. Another important use of DNA fingerprints in the court system is to establish paternity in custody and child support litigation.
In these applications, DNA fingerprints bring an unprecedented, nearly perfect accuracy to the determination.
Personal identification
Because every organ or tissue of an individual contains the same DNA fingerprint, the U.S. armed services have just begun a program to collect DNA fingerprints from all personnel for use later, in case they are needed to identify casualties or persons missing in action.
The DNA method will be far superior to the dogtags, dental records, and blood typing strategies currently in use.
(a) Explain the principle involved in genetic engineering [2 marks]
(b) Discuss the importance of genetic engineering in the medical and agricultural field. [ 4 marks] (c) Diagram shows DNA finger printing. DNA finger printing is more scientific, accurate and advanced compared to the thumbprint in criminal investigation.
Discuss the use of DNA fingerprinting in the identification of the parents of a child. [4 marks]
Answer:
(a) Genetic engineering is a technique of manipulating the genes in an organism by removing a gene from one organism
and transferring it to another organism.
(b)
The importance of genetic engineering in the medical field.
· Production of insulin from bacteria.
· Gene from the pancreas that can produce insulin is removed and inserted into the DNA molecule of bacteria.
· The bacteria that can produce insulin grows very fast in a suitable nutrient medium.
·Insulin can be produced in large quantities in a short time. [ any 2]
Genetic engineering in agriculture.
·Produce food or plants which are genetically modified to produce high quality yield.
·Produce plants with high quality yield as they are resistant to viral attacks, pesticides or predators. [ 2 marks]
(c)
· DNA fingerprinting is a technique used to identify parents of a child based on DNA banding similarity
· Generally, the DNA profile of a child is the combination of the mother and father.
· A child inherit half of the chromosomes number from father and half from mother.
· DNA fingerprinting gives more details and information regarding the identity of a person while thumbprints give general information as it is based on a few different types.
·A blood sample, seminal fluid or any tissue can be analysed and its result is compared with that of an individual who is a suspect.
·In conclusion, the father of the child has the similarity of his DNA
Brief Account:
- Like the fingerprints that came into use by detectives and police labs during the 1930s, each person has a unique DNA fingerprint .
- Unlike a conventional fingerprint that occurs only on the fingertips and can be altered by surgery, a DNA fingerprint is the same for every cell, tissue, and organ of a person.
- It cannot be altered by any known treatment.
- Consequently, DNA fingerprinting is rapidly becoming the primary method for identifying and distinguishing among individual human beings.
- An additional benefit of DNA fingerprint technology is the diagnosis of inherited disorders in adults, children, and unborn babies.
- Even bloodstained clothing from Abraham Lincoln has been analyzed for evidence of a genetic disorder called Marfan's Syndrome.
Uses of DNA Fingerprints
DNA fingerprints are useful in several areas of society. They are used by professionals in human health and the justice system.
Diagnosis of inherited disorders
DNA fingerprinting is used to diagnose inherited disorders in both prenatal and newborn babies in hospitals around the world.
These disorders may include cystic fibrosis, hemophilia, Huntington's disease, familial Alzheimer's, sickle cell anemia, thalassemia, and many others.
Early detection of such disorders enables the medical staff to prepare themselves and the parents for proper treatment of the child.In some programs, genetic counselors use DNA fingerprint information to help prospective parents understand the risk of having an affected child.
In other programs, prospective parents use DNA fingerprint information in their decisions concerning affected pregnancies.
Developing cures for inherited disorders
Research programs to locate inherited disorders on the chromosomes depend on the information contained in DNA fingerprints.
By studying the DNA fingerprints of relatives who have a history of some particular disorder, or by comparing large groups of people with and without the disorder, it is possible to identify DNA patterns associated with the disease in question.
This work is a necessary first step in designing an eventual genetic cure for these disorders.
Forensic or criminal
FBI and police labs around the U.S. have begun to use DNA fingerprints to link suspects to biological evidence-blood or semen stains, hair, or items of clothing-found at the scene of a crime. Another important use of DNA fingerprints in the court system is to establish paternity in custody and child support litigation.
In these applications, DNA fingerprints bring an unprecedented, nearly perfect accuracy to the determination.
Personal identification
Because every organ or tissue of an individual contains the same DNA fingerprint, the U.S. armed services have just begun a program to collect DNA fingerprints from all personnel for use later, in case they are needed to identify casualties or persons missing in action.
The DNA method will be far superior to the dogtags, dental records, and blood typing strategies currently in use.
Saturday, November 21, 2009
Placental Function- (SPM Paper 2 2009)
- The placenta begins to form and grow during the first 4 weeks, due to the tissue of the embryo invading the wall of the uterus.
- The placenta is soft and has capillaries filled with the embryo’s blood.
- The wall of the uterus has large spaces filled with the mother’s blood. The wall of the placenta is very thin which brings the mother’s blood supply alongside the foetus to allow the exchange of food and oxygen to the foetus, and for the foetal waste and carbon dioxide to transfer to the mother.
- The blood of the mother and foetus do not mix, but substances are exchanged through the placenta by diffusion.
- The developing foetus does not breathe within the uterus, but instead it uses the placenta to get what it needs to develop and survive.
• metabolism,
• transport of substances and
• in endocrine secretion.
Metabolism:
• During early pregnancy, the placenta synthesizes glycogen, cholesterol and fatty acids, which serve as sources of nutrients and energy for the embryo and fetus.
Transport:
• The placenta has a very large surface area, which facilitates the transport of substances in both directions. The bulk of the substances transferred from mother to fetus consists of oxygen and nutrients.
• The fetus eliminates carbon dioxide and waste materials (eg., urea and bilirubin) into the maternal circulation.
• The exchange of gases occurs via diffusion.
• The placenta is also highly permeable to glucose,
• Amino acids are transported through speciic receptors.
• The transfer of maternal antibodies is important in providing passive immunity to the newborn.
• The placenta is also very permeable to alcohol and other drugs and to some viruses. These agents can cause birth defects.
Placental hormone synthesis:
i. Human chorionic gonadotropin (hCG):
• Synthesis of hCG begins before implantation, and is responsible for maintaining the maternal corpus luteum that secretes progesterone and estrogens.
• It is the basis for early pregnancy tests.
• Production peaks at eight weeks and then gradually declines.
ii.Estrogens and progesterone
• the placenta produces enough of these steroids to maintain the pregnancy and the corpus luteum is no longer needed.
The umbilical cord
- Oxygen and food materials in the mother’s blood diffuse across the placenta into the embryo’s blood and then carried along the umbilical cord to the embryo.
- Carbon dioxide and waste diffuse the other way and are carried away in the mother’s blood.
- The umbilical cord connects the baby to the mother’s placenta.
- The cord contains an artery, which carries waste products from the developing baby to the placenta,
- and a vein, which carries the food and oxygen to the foetus from the mother.
The amnion
A strong membrane called the amnion, which makes a fluid called amniotic fluid, protects the developing baby.This helps to protect the foetus from being damaged by the mother during her normal activities over the nine months of development.
**Spot dan kena!
Autosome Vs Sex Chromosome
Some of you might be a bit blur about these two terms:
What is Autosome? (Some of the definitions..quoted)
-A chromosome other than a sex chromosome,
- normally occurring in pairs in somatic cells and singly in gametes
-Autosomes control the inheritance of all the characteristics except the sex-linked ones, which are controlled by the sex chromosomes. Humans have 22 pairs of autosomes and one pair of sex chromosomes
-Autosomes are all the chromosomes other than the X and Y chromosomes
-They are two copies of each autosome (chromosomes 1-22) in both females and males
in humans there are 22 pairs of autosomes
-A chromosome not involved in sex determination
-any chromosome that is not a sex chromosome and that appears as a homologous pair in a somatic cell.
Humans have 22 pairs of autosomes, which transmit all genetic traits and conditions other than those that are sex-linked
What is Sex chromosome? (Some of the definitions...quoted)
-Each person normally has one pair of sex chromosomes in each cell.
-Females have two X chromosomes, whereas males have one X and one Y chromosome.
-Both males and females retain one of their mother's X chromosomes, and females retain their second X chromosome from their father.
-Since the father retains his X chromosome from his mother, a human female has one X chromosome from her paternal grandmother, and one X chromosome from her mother.
-The nuclei of human cells contain 22 autosomes and 2 sex chromosomes.
In females, the sex chromosomes are the 2 X chromosomes.
-Males have one X chromosome and one Y chromosome. The presence of the Y chromosome is decisive for unleashing the developmental program that leads to a baby boy.
What is Autosome? (Some of the definitions..quoted)
-A chromosome other than a sex chromosome,
- normally occurring in pairs in somatic cells and singly in gametes
-Autosomes control the inheritance of all the characteristics except the sex-linked ones, which are controlled by the sex chromosomes. Humans have 22 pairs of autosomes and one pair of sex chromosomes
-Autosomes are all the chromosomes other than the X and Y chromosomes
-They are two copies of each autosome (chromosomes 1-22) in both females and males
in humans there are 22 pairs of autosomes
-A chromosome not involved in sex determination
-any chromosome that is not a sex chromosome and that appears as a homologous pair in a somatic cell.
Humans have 22 pairs of autosomes, which transmit all genetic traits and conditions other than those that are sex-linked
What is Sex chromosome? (Some of the definitions...quoted)
-Each person normally has one pair of sex chromosomes in each cell.
-Females have two X chromosomes, whereas males have one X and one Y chromosome.
-Both males and females retain one of their mother's X chromosomes, and females retain their second X chromosome from their father.
-Since the father retains his X chromosome from his mother, a human female has one X chromosome from her paternal grandmother, and one X chromosome from her mother.
-The nuclei of human cells contain 22 autosomes and 2 sex chromosomes.
In females, the sex chromosomes are the 2 X chromosomes.
-Males have one X chromosome and one Y chromosome. The presence of the Y chromosome is decisive for unleashing the developmental program that leads to a baby boy.
Sickle Cell anaemia
Its another case of inheritance of traits on autosomal chromosome..Sickle-cell disease, or sickle-cell anaemia is a life-long blood disorder .Characterized by red blood cells that assume an abnormal, rigid, sickle shape.
Sickling decreases the cells' flexibility and results in a risk of various complications.
The sickling occurs because of a mutation in the hemoglobin gene.
Sickle cell disease results when a person inherits an allele for sickle-cell hemoglobin from each of his or her parents.
This inheritance pattern means that the person is homozygous for sickle-cell hemoglobin and that his or her body does not produce any normal hemoglobin, but only sickle cell hemoglobin.
Geneticists show the inheritance pattern of sickle-cell disease by using symbols to represent the allele for normal hemoglobin (Hb A) and the allele for sickle-cell hemoglobin (HB S). A person with normal hemoglobin has inherited one allele for normal hemoglobin from each parent and so has the genotype Hb A/Hb A. In contrast, a person who has sickle disease has inherited one sickle-cell allele from each parent and has the genotype Hb S/Hb S.
But what about a person who inherits an allele for normal hemoglobin from one parent and an allele for sickle-cell hemoglobin from the other parent? This person has the genotype Hb A/Hb S, and is said to have sickle-cell trait.
Although some of the hemoglobin in this person's body is sickle-cell hemoglobin, the rest of the hemoglobin is normal, and the person usually exhibits no symptoms of the disease.
..The genetic Diagram is similar to albinism...just change the KEY..
Albinism
AUTOSOMAL RECESSIVE INHERITANCE that is: Inheritance of traits on Autosomal chromosomes:
...such as Albinism and Sickle Cell Anaemia:
Albinism (from Latin albus, meaning "white"),
-a disorder, characterized by a lack of pigment in the eyes, skin and hair (or more rarely the eyes alone).
-Albinism results from inheritance of recessive genes.
-Albinism is a genetic disorder; it is not an infectious disease and cannot be transmitted through contact, blood transfusions, etc.
-The principal gene which results in albinism prevents the body from making the usual amounts of the pigment melanin.
-Most forms of albinism are the result of the biological inheritance of genetically recessive alleles (genes) passed from both parents of an individual, though some rare forms are inherited from only one parent.
-There are other genetic mutations which are proven to be associated with albinism.
-For nearly all types of albinism both parents must carry an albinism gene to have a child with albinism.
-Because the body has two sets of genes,a person may have normal pigmentation but carry the albinism gene.
-If a person has one gene for normal pigmentation and one gene for albinism, he or she will have enough genetic information to make normal pigment.
-The albinism gene is "recessive" — it does not result in albinism unless a person has two copies of the gene for albinism and no copy of the gene that makes normal pigment.
-When both parents carry the gene, and neither parent has albinism, there is a one in four chance at each pregnancy that the baby will be born with albinism.
-This type of inheritance is called autosomal recessive inheritance.
...such as Albinism and Sickle Cell Anaemia:
Albinism (from Latin albus, meaning "white"),
-a disorder, characterized by a lack of pigment in the eyes, skin and hair (or more rarely the eyes alone).
-Albinism results from inheritance of recessive genes.
-Albinism is a genetic disorder; it is not an infectious disease and cannot be transmitted through contact, blood transfusions, etc.
-The principal gene which results in albinism prevents the body from making the usual amounts of the pigment melanin.
-Most forms of albinism are the result of the biological inheritance of genetically recessive alleles (genes) passed from both parents of an individual, though some rare forms are inherited from only one parent.
-There are other genetic mutations which are proven to be associated with albinism.
-For nearly all types of albinism both parents must carry an albinism gene to have a child with albinism.
-Because the body has two sets of genes,a person may have normal pigmentation but carry the albinism gene.
-If a person has one gene for normal pigmentation and one gene for albinism, he or she will have enough genetic information to make normal pigment.
-The albinism gene is "recessive" — it does not result in albinism unless a person has two copies of the gene for albinism and no copy of the gene that makes normal pigment.
-When both parents carry the gene, and neither parent has albinism, there is a one in four chance at each pregnancy that the baby will be born with albinism.
-This type of inheritance is called autosomal recessive inheritance.
Refer your Reference Book as how to write the genetic chart correctly....Make sure do not use XX and XY because it does not involve sex chromosome!!
Monday, November 16, 2009
Sex-linked diseases-Sex Chromosomes
Sex linked genes is the phenotypic expression of an allele that is related to the chromosomal sex of the individual.
This mode of inheritance is in contrast to the inheritance of traits on autosomal chromosomes, where both sexes have the same probability of expressing the trait.
Since, in humans, there are many more genes on the X than there are on the Y, there are many more X-linked traits than there are Y-linked traits.
In mammals, the female is the homogametic sex, having two X chromosomes (XX), while the male is heterogametic,
having one X and one Y chromosome (XY). Genes that are present on the X or Y chromosome are called sex linked genes.
As for your SPM, the diseases focussed are : Haemophilia and Coloured-blindness..
Take special care when constructing the genetic Diagrams to show the ratio of the offsprings...
Refer your Reference Book for details of the Diagram..
This mode of inheritance is in contrast to the inheritance of traits on autosomal chromosomes, where both sexes have the same probability of expressing the trait.
Since, in humans, there are many more genes on the X than there are on the Y, there are many more X-linked traits than there are Y-linked traits.
In mammals, the female is the homogametic sex, having two X chromosomes (XX), while the male is heterogametic,
having one X and one Y chromosome (XY). Genes that are present on the X or Y chromosome are called sex linked genes.
As for your SPM, the diseases focussed are : Haemophilia and Coloured-blindness..
Take special care when constructing the genetic Diagrams to show the ratio of the offsprings...
Refer your Reference Book for details of the Diagram..
ABO blood Group- Antibody Vs Antigen
I hope these Diagrams help you to understand better what is Antibody and Antigen of Red Blood cells/ erythrocytes.
If blood clumps with both anti-A and Anti-B serum, then your blood group is AB.
If blood clumps with both anti-A and Anti-B serum, then your blood group is AB.
ABO blood Group
According to the AB0 blood typing system there are four different kinds of blood types: A, B, AB or 0
If you belong to the blood group A, you have A antigens on the surface of your red blood cells and B antibodies in your blood plasma.
If you belong to the blood group B, you have B antigens on the surface of your red blood cells and A antibodies in your blood plasma.
If you belong to the blood group AB, you have both A and B antigens on the surface of your red blood cells and no A or B antibodies at all in your blood plasma.
If you belong to the blood group 0 (null), you have neither A or B antigens on the surface of your red blood cells but you have both A and B antibodies in your blood plasma
If you belong to the blood group A, you have A antigens on the surface of your red blood cells and B antibodies in your blood plasma.
If you belong to the blood group B, you have B antigens on the surface of your red blood cells and A antibodies in your blood plasma.
If you belong to the blood group AB, you have both A and B antigens on the surface of your red blood cells and no A or B antibodies at all in your blood plasma.
If you belong to the blood group 0 (null), you have neither A or B antigens on the surface of your red blood cells but you have both A and B antibodies in your blood plasma
Menstrual Cycle-Negative feedback mechanism
- The Menstrual cycle is a feedback mechanism because it is regulated by hormones which are controlled by negative feedback mechanisms. This mechanism includes hormones that are interacted with tissues in the menstrual cycle.
The female menstrual cycle is determined by a complex interaction of hormones.
The predominant hormones involved in the menstrual cycle are
-gonadotropin releasing hormone (GnRH),
-follicle stimulating hormone (FSH),
-luteinizing hormone (LH),
-estrogen, and progesterone.
GnRH is secreted by the hypothalamus, the gonadotropins FSH and LH are secreted by the anterior pituitary gland,
and estrogen and progestin are secreted at the level of the ovary.
GnRH stimulates the release of LH and FSH from the anterior pituitary, which in turn stimulate release of estrogen and progestin at the level of the ovary
Follicle stimulated hormone (FSH) is secreted by the anterior pituitary gland and is essential for follicular growth
FSH induces estrogen and progesterone secretion and has negative feedback on GnRH secretion.
Estrogen is produced at the level of the ovary and is crucial for the development of and maturation of the Graafian follicle.
At low circulating levels, estrogens exert negative feedback on LH and FSH secretion; however, at very high levels estrogens exert positive feedback on LH and FSH secretion.
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