BIO ESSAY ~ repost

The following TIPS may be 'common' and a 'familiar' tips which are told by your Bio teachers over and over again...BUT I'm sure all of you still take it lightly...especially when the examination paper is right infront of you......suddenly all the tips are forgotten.......so unfortunate..........then you are the loser!

COMMON but IMPORTANT TIPS in answering BIO ESSAYS are:

1. READ THE QUESTION CAREFULLY

2. HIGHLIGHT the COMMAND word in the question such as Explain, Describe,Compare...so that you know what you are supposed to do..

3.Plan your ESSAY...(by roughly sketching mind map, flow chart, diagram etc )

4.LOOK at THE MARKS allocated.(This give you idea how long your essay should be )

5.Answer in paragraphs if it is a long essay.

6. Tables are allowed only for COMPARING

7.Write at least 2 pages (including half page of Diagram)

8. Produce Diagram to support your answer but make sure it is all labelled!!

9.Give Facts + Explanation for every answer..

10.Write as long as you like..Never mind if it is wrong..you wont be penalize.

11. Do not write in a point form...because it is ESSAY !!!

12.Choose only TWO essays if the instruction is TWO!!

13.....Write and keep on writing.....Produce all the facts that you ever remember..

( BIO PAPER 2 need you to master BIO CONTENT very well !)

.........LAstly, your choice of questions must be correct....Chose the questions which you know the content very well...at least 80-100% content..

..and of course write clearly and confidently...may use your own words.. as long as it conveys the same meaning.

...ALL THE BEST FOR YOUR SPM  EXAMINATION.

Phagocytosis

...When you learn about the process called PHAGOCYTOSIS' you must make sure to be able to describe the process right from the beginning: ..approaching, surrounding, engulfing, digesting...finally release the unwanted substances..Dont forget the involvement of lysozyme!...Phagocytosis also occurs in white blood cells , particularly : neutrophyll and monocyte...Is it correct ?
**The video might help you to visualise the process..

Watch out for pseudopodium!
Thank You for the source..

Enzymes involved in Digestion

Digestion is done physically and chemically. There are many involvement of enzymes in digestion process.

Name all the enzymes involved and its substract (Classes of food) and products in the following structures of the alimentary canal :
1. Mouth [2 marks]
2. Stomach [4 marks]
3. Duodenum [ 8 marks]
4. Ileum [ 8 marks]

The Stages of Digestion

A clear and interesting video to show the stages of digestion..Especially to all Form 4 students..BUT as for the questions which might be asked in an examination, you should know how to EXPLAIN what happen to FOOD at each parts /structures of the alimentary canal such as in :
Mouth?
stomach?
duodenum?
Ileum? in colon?

Study the events occur which are related with Enzymes involved!!

Bio CD

Hello everybody..

I'm calling all Bio teachers in particular.....be it in Kuala Lumpur or all over Malaysia.... ...announcing that Guru Cemerlang Biologi Kuala Lumpur have compiled materials which are useful and might be needed by Bio teachers all over Malaysia....in a form of CD.

The contents are :

1.The Chapters Review of selected Chapters of Form 4 and Form 5 in a Power Point Presentation.

2. Notes in Words of all topics in Biology

3. Koleksi Rajah Bio

4....and materials which can support yout T& L process.

If you are interested, do contact me : mahadiah@gmail.com to place your order by giving your name, add and the quantity.. It cost only RM5.00 per piece...and if you are out of KL, extra RM5 for packaging and postage ..please..

TQ.....The selling is for our Majlis Guru Cemerlang Biologi Kuala Lumpur :-)...Support us!

The digestion process - Digestive System

What happens to your food as it travels through your digestive system?

This video would be a great help for the form 4 students to visualise what happen in the alimentary tract..Then ..teacher might ask students to DESCRIBE in an ESSAY as what happen to the food starting from mouth until the end- Out as faeces!

Thanks to McGraw Hill..

DNA Fingerprinting

Thumbprints and fingerprints have been widely used in criminal investigation. Today, there is a new technique to detect suspects in criminal activities..It is known as DNA fingerprinting.

DNA fingerprinting is a PROCEDURE used to analyse a person's unique collection of DNA fragments. This is because each person has his own set of DNA which is unique to him.

The patterns of these DNA fragments or DNA fingerprints can be used by police to identify an individual. For example, DNA from tissue samples of hair, saliva, blood, semen found at the scene of a crime can be compared to those of a suspect.

DNA fingerprinting can also be used :

-to screen genetic disorders.

-to track genes responsible for causing certain diseases.

-to test the compatibility of potential organ donors with aptients.

Thank You Britannica.com for sharing.

**As for your SPM examination: Question might be asked :

1. What is the difference between fingerprint technique and DNA fingerprinting? [4 marks]

2. Explain what is DNA fingerprinting and its uses. [5 marks]

3. Explain the advantages of DNA fingerprinting over the fingerprint technique. [6 marks]

DNA Structure

DNA is made up of nucleotides.... Each nucleotide consist of Phosphate, Pentose sugar (Deoxyribose) and Nitrogenous Bases..Name the four bases please !

Greenhouse Effect Versus Global Warming

Greenhouse effect and Global warming are very much related to one another.. Lets go through the following extract to differentiate between the two :

Global warming, a recent warming of the Earth's surface and lower atmosphere is believed to be the result of a strengthening of the greenhouse effect mostly due to human-produced increases in atmospheric greenhouse gases.

What Causes the Greenhouse Effect?

Life on earth depends on energy from the sun. About 30 percent of the sunlight that beams toward Earth is deflected by the outer atmosphere and scattered back into space. The rest reaches the planet's surface and is reflected upward again as a type of slow-moving energy called infrared radiation.

The heat caused by infrared radiation is absorbed by "greenhouse gases" such as water vapor, carbon dioxide, ozone and methane, which slows its escape from the atmosphere.

Although greenhouse gases make up only about 1 percent of the Earth's atmosphere, they regulate our climate by trapping heat and holding it in a kind of warm-air blanket that surrounds the planet. This phenomenon is what scientists call the "greenhouse effect."

Without it, scientists estimate that the average temperature on Earth would be colder by approximately 30 degrees Celsius (54 degrees Fahrenheit), far too cold to sustain our current ecosystem...(So actually we need the 'green house effect!!)

How Do Humans Contribute to the Greenhouse Effect?

While the greenhouse effect is an essential environmental prerequisite for life on Earth, there really can be too much of a good thing.
The problems begin when human activities distort and accelerate the natural process by creating more greenhouse gases in the atmosphere than are necessary to warm the planet to an ideal temperature.
· Burning natural gas, coal and oil -including gasoline for automobile engines-raises the level of carbon dioxide in the atmosphere.
· Some farming practices and land-use changes increase the levels of methane and nitrous oxide.
· Many factories produce long-lasting industrial gases that do not occur naturally, yet contribute significantly to the enhanced greenhouse effect and "global warming" that is currently under way.
· Deforestation also contributes to global warming. Trees use carbon dioxide and give off oxygen in its place, which helps to create the optimal balance of gases in the atmosphere. As more forests are logged for timber or cut down to make way for farming, however, there are fewer trees to perform this critical function.
· Population growth is another factor in global warming, because as more people use fossil fuels for heat, transportation and manufacturing the level of greenhouse gases continues to increase. As more farming occurs to feed millions of new people, more greenhouse gases enter the atmosphere.

Ultimately, more greenhouse gases means more infrared radiation trapped and held, which gradually increases the temperature of the Earth's surface and the air in the lower atmosphere.

What is Being Done to Reduce Global Warming?

To lessen those long-term effects, many nations, communities and individuals are taking action now to reduce greenhouse gas emissions and

slow global warming by reducing dependence on fossil fuels,

increasing the use of renewable energy,

expanding forests, and making lifestyle choices that help to sustain the environment.

Global Warming~ as a whole..

Independent Assortment-Mendel's Law 2

Stem Cell Research

A stem cell is a basic cell which can divide and develop into cells with particular functions. Other cells in the body 'stem' from this type of cells (hence, the name stem cells ).

Stem cells are undiffrentiated cells that can undergo unlimited division to form other cells. This means stem cells are capable of dividing and renewing themselves, unlike other body cells.
They are also unspecialised which can potentially become any type of cells.
They differentiate to form specialised functioning body cells such as skin cells, red blood cells, nerve cells, and skeletal muscle cells under certain condition.
They remain in the body until they get a signal to diffrentiate or gradually change into the desired cell type. This occurs when specific genes in the stem cell are turned on.This process helps cells to specialise so they can carry out different function.

There are two types of stem cells:
1. the embryonic stem cells.
2.An adult stem cells.

Please Google to find out more!

SPM possible Question:

1. Explain briefly the potential of stem cell research to man. [ 5 marks]

*Try the video to understand better.

Synapse

The nervous system, a synapse is a junction that permits a neuron to pass an electrical or chemical signal to another cell.

Synapses are essential to neuronal function: neurons are cells that are specialized to pass signals to individual target cells, and synapses are the means by which they do so.

At a synapse, the plasma membrane of the signal-passing neuron (the presynaptic neuron) comes into close apposition with the membrane of the target (postsynaptic) cell. Both the presynaptic and postsynaptic sites contain extensive arrays of molecular machinery that link the two membranes together and carry out the signaling process.

In many synapses, the presynaptic part is located on an axon, but some presynaptic sites are located on a dendrite or soma.

Kidney in homeostasis

Students may use this animated video to learn more about the kidney function. Please click at the image above to directly view the video.

Sample Qs-Microorganism

1.(a) State the difference between bacteria and virus in the following aspect : [3m]
i. Structure
ii.Method of reproduction
iii.Nutrition.
(b) (i) Parasites can cause diseases. State 3 main ways how parasitic diseases can be
transmitted in a community . [3m]
(ii) Ringworm is a disease caused by fungus. Explain how transmission of this pathogen
can be stopped. [3m]
(c) Microorganisms can be useful to human. Explain the importance of microorganisms :
(i) In food industry. [3m]
(ii) In Nitrogen cycle [3m]
(iii) Production of insulin [3m]

Suggested Answer:

1(a)Structure :
- Bacteria enclosed by cell wall made of glycoprotein, but virus only have protein coat // Bacteria have nucleus but virus only contain RNA / DNA

Method of reproduction :
- Bacteria reproduce asexually by binary fission , but virus only replicate the DNA/RNA in the host

Nutrition :
- Bacteria can be synthesis organic substances via chemosynthesis (autotroph) or feed organic substances from other organisms (heterotroph) but viruses are strickly parasit (absorp nutrient from the host)

(b)(i)- vector such as rat, housefly or others
- by food / water
- by droplet transmission
(ii)- do not share clothes with others
- wash / clean all part of your body and make sure it dry
- use anti-fungus cream
- take vitamin C
(c) (i)- Yeast used in cake industry / wine industry
- bacteria used in chocolate / dairy product industry
- fungus used as a food
(ii)- Nitrogen fixing bacteria convert the nitrogen gas to nitrates in the soil (example Rhizobium sp and Nostoc)
- Bacteria and fungi decompose dead organisms to form ammonia
- Nitrosomonas and nitrobacter convert ammonia to nitrites and nitrites to nitrates.
(iii)- Fragmen of DNA which control the formation of insulin from pancreas was inserted in the DNA of bacteria
- That bacteria will be cultured in a specific medium.
-That bacteria has ability to produce insulin in big amount and faster.

Sample Qs-Pond ecosystem

1.Figure 1 shows pond ecosystem.

(a) (i) Based on Figure 1, name TWO factors for each of the following:-

-Biotic factor

-Abiotic factor [4m]

(ii) Name the abiotic factor that controls the distribution of submerged plants in the pond. [1m]

(iii) State the relationship between the factor you have named in (a)(ii) and the distribution of submerged plants. [1m]

(b) (i) Based on Figure 1, construct :
- A food web showing the interaction of all the organisms in the figure. [2m]

- A pyramid of numbers consisting of four trophic levels [2m]

(ii) Explain how energy is transferred from the sun to the organisms in food chain. [3m]

(iii) Explain why the amount of energy received by an organism via the food chain gradually decreases from one trophic level to the other trophic levels. [3m]

(c) (i) Name the organism that is known as the pioneer species in the pond. [1m]

(ii) Most of the pioneer species have adaptations that enable them to live in the bare
habitat. Give TWO adaptations of the pioneer species you have named in (c)(i). [2m]

(iii) Explain how the ecosystem in Figure 1 can turn into a climax ecosystem. [5m]

(d) Vegetables were planted near the pond in Figure 1. A farmer used chemical fertilizers to
enhance the growth of the vegetables. He also used pesticide to control the pests.
Predict the effects arising from those activities to the pond ecosystem after several years. [5m]

Suggested Answer:

1(a)(i) Biotic factor : Producer, consumer
Abiotic factor : light intensity, pH of water , depth of the pond.

(ii)light intensity

(iii)The lower the light intensity in the pond, the higher the population of submerged plant

(b)(i)Marks given for : all organisms correct- 1 , arrow correct - 1

(ii)- light energy trap by chlorophyll (in producers) and changed to chemical
energy in food (via photosynthesis)
- producer eaten by primary consumer, so energy from producer transfer to
the primary consumer
- primary consumer eaten by other consumer, so energy will transfer to that
organism via feeding

(iii)- energy lost directly from organisms to the surrounding through radiation
- lost through excretion such as urination, constipation and sweating
- lost through respiration

(c)(i)Hydrilla sp. / Elodea / Cabomba

(ii)- Reproduce asexually
- need only low light intensity to carry out photosynthesis

(iii)- submerged plants died and sink at the bottom of the pond, it change the
nutrient content and depth of the pond.
- submerged plants replaced by the floating plants, which at the end covered
surface of the water
- light cannot enter the inner part of the pond, so all submerged plants will
die and the pond become more shallow
- now the amphibian plants will replace the floating plant, and the pond
become less water
- at the end , terrestrial plants will take over the pond and form the climax
community

(d)Pesticide :-
- the toxic substances accumulate in the organisms via the food chain
- the concentration of toxic become higher as the trophic level increase
- this will cause extinction

Fertilizers :-
- more nitrates and phosphates in the pond
- enhance the growing of floating plants which caused algal bloom
- this will reduce amount of oxygen in the pond; situation known as eutrophication

Spermatogenesis Vs Oogenesis

I guess all of you have learnt a lot about these two processes..Just to remind you the possible scope of questions are mainly:

1. The schematic diagram of spermatogenesis and Oogenesis which shows the changes of chromosome numbers and where are the meiosis I, meiosis II , mitosis, differentiation take place...Please take note for each steps of the development!!!.

2. The Diagram of the cross section of the Ovary and the seminiferous tubule which show the development of the structures starting with Primordial germ cells. (2n)...and the final products : Secondary oocyte for the oogenesis and spermatozoa for spermatogenesis..

Click ON the image to VIEW The Video

**Spermatogenesis schematic diagram came out for SPM Paper 2 structure 2009!!!

Stages Of Meiosis

Just CLICK on the image to watch the animation .

Sample Qs: The thinning of ozone layer

1. The thinning of the ozone layer is an environmental issue which is always being discussed. Describe the effect of the thinning of the ozone layer on the environment and living organisms on the earth. Suggest different ways to solve this problem.
[10marks]

Suggested Answer: (ANy 10 marks)

The effect:
P1 - More UV rays / ultraviolet radiation reaches the earth’s surface.
P2 - Increase of temperature.
P3 - UV ray will deteriorate one’s body immunity system.
P4 - An increase in the number of people suffering from skin cancer and cataract.
P5 - High UV rays destroy microorganisms and phytoplankton (the producer of marine food chain).
P6 - Rate of photosynthesis decrease.
P7 - High level of UV rays can damage the eggs of certain amphibians.

Steps to solve the problem:
P8 - Reduce / stop using CFCs.
P9 - Replace CFCs with HCFCs.
P10- Use wrapping papers instead of polystyrene boxes.
P11- Patch up the holes in the ozone layer by firing frozen ozone balls into the atmosphere.

Sample Qs-Greenhouse effect

a) Diagram 9 shows sources of greenhouse gases from human activities and natural processes Explain the sources of greenhouse gases. [10marks]

Suggested Answer:

-Sources of greenhouse gases;
F1- Emission from exhaust of motor vehicles (1m)
E1- release a lot of carbon dioxide gas and into atmosphere (1m)

F2- Combustion of fossil fuel in factories (1m)
E2- releases a large amount of carbon dioxide gas into atmosphere (1m)
E3- and also releases oxides of nitrogen (1m)

F3- Uses of aerosol spray/air conditioner (1m)
E4- with contains CFC (1m)
E5- CFC cause ozone depletion with bring about greenhouse effect (1m)

F4- Fermentation in ruminant animals / anaerobic fermentation in paddy field (1m)
E6- release methane gas into atmosphere (1m)

F5- use of inorganic fertilizer (1m)
E7- cause release of nitrogen oxide gas (1m)

Sample Qs- Microorganism

1. Most microorganisms are harmless and useful to humans. Yeast and bacteria are microorganisms. Discuss the benefits of using this two microorganisms to produce useful products for humans. [ 10 marks]

Suggested Answer:

Medical Purpose : ( Any 4)
Antibiotic
· Antibiotic are chemicals which either inhibit the growth of or kill other microorganisms, especially disease-causing bacteria
· Example : streptomycin is produced by Streptomycin sp.
· Penicillin is produced by the fungus Penicillium chrysogenum sp.
· The fungus is grown in large fermenters, and the antibiotic produced is then isolated and purified

Immunisation ( 1 mark)
· The vaccine that contains weakened or dead microorganism which stimulates the body to produce antibodies.

Food Processing Industry
Wine ( 2 marks)
· Wine is made by adding yeast to fruit sugar (glucose) from grapes.
· The yeast converts glucose in grapes into alcohol during anaerobic respiration / fermentation

Bread ( 2 marks)
· Bread is made from yeast, flour,sugar and water. The most commonly used species of yeast is Saccharomyces cerevisiae.
· Fermentation by yeast produces ethanol and carbon dioxide. The carbon dioxide causes the dough to rise

Soya Sauce ( 1mark)
· Soya sauce is made from fermented soya beans caused by the action of fungi.
**Or any suitable answer

Sample Qs-Digestive system

1. Describe the digestive actions that take place in the
(i) mouth
(ii) stomach
(iii) small intestine

Explain the roles of the glands secretion and enzymes involved in these digestive process.
(10 marks)

Suggested Answer:

Mouth
· Food is chewed and broken up into smaller pieces by the teeth.
· The small pieces of food have a larger surface area for the saliva (enzyme) to act upon.
· Salivary gland secretes saliva (that is alkaline and )contains salivary amylase (ptyalin).
· ( After the food has been thoroughly chewed and mixed with saliva) the tongue starts the process of swallowing by pushing the bolus (small mass of chewed food).
· Saliva also softens and increases the water content of the food.
· In mouth, only starch is digested.
- Starch is hydrolysed by amylase into maltose.
(Starch + Water .....Amylase ....... Maltose ) [ any 3 points]

Stomach
-Secretes gastric juices contains hydrochloric acid and enzyme (rennin and pepsin)
-Hydrochloric acid kills microorganisms and stops the activity of salivary amylase, (which functions optimally at the near-neutral pH of saliva )
- and promotes the activity of pepsin.
-Pepsin is a (hydrolytic ) enzymes that acts on protein to produce peptides
( Protein + Water .... pepsin .... Peptone + polypeptide )
- Rennin changes caseinogens to casein.
- Casein is then digested by pepsin

Ileum (small intestine) :
· There are some digestive glands on small intestine.
-All these enzymes need an alkaline medium function
· There are 5 types of enzymes produced :
1. Erypsin (peptidase) – hydrolysis of peptide to amino acids
2. Sucrase - hydrolysis of sucrose to fructose and glucose
3. Maltase - hydrolysis of maltose to glucose
4. Lactase - hydrolysis of lactose to glucose and galactose
5. Entrokinase – Activates trypsinogen to trypsin in the
duodenum.
Any of the above enzymes reaction - 4 marks

Sample Qs -Double fertilisation

Diagram 8 shows a cross section through the ovary and pollen tube of a flowering plant just before fertilisation.(a) With the aid of Diagram 8, explain the development of an embryonic sac [5 marks]

(b)(i)Explain the mechanism of double fertilisation. [10 marks]

(ii)Explain the importance of double fertilization for the survival of flowering plants

[5 marks]

Suggested Answer:

(a)

-The complete development of each ovule takes place beginning with an embryosac mother cell
-The embryonic mother cell (diploid cells) divide by meiosis to form haploid cells
-3 of them degenerate
-The nucleus of the 1 haploid cell remaining divides by mitosis
-This produces 2 haploid nuclei, which again divide by mitosis
-This produces 4 haploid nuclei, which again divide by mitosis
-Finally this produces 8 haploid nuclei, and the structure is known as a mature embryo sac

Any 3 points [ 3 marks]

Drawing 2 marks: Correct drawing and Labels.

* May use diagram from any reference book

(b)(i)
-Pollen reaches a stigma and sticks to the surface
-A pollen tube begins to grow from the pollen grain
-The proteins for this tube are produced with the help of the tube nucleus which remains near the tip of the tube
-The generative nucleus divides into 2 male nuclei which follow down the tube
-The pollen tube grows into an ovule
-One male nucleus fuses with the egg cell forming a diploid zygote;
-this (divides many time to ) form the embryo of the seed
-The other male nucleus fuses with two polar nuclei forming a triploid cell;
-this (divides many times to )form the endosperm of the mature seed.

-This is double fertilization because of the fusion to form the diploid zygote and the primary endosperm cell. [10 maximum]

(ii)

F1 This results in genetic and morphological diversity:
P1 During fertilization there is a random fusion of gametes
with the egg cells
P2 As a result every plant is different from the mother plant as
well as each other

F2 This diversity helps plant to adapt to climatic changes and
wider range of habitats:
P1 Therefore plants are able to colonize large areas of land

F3 The development of seeds with its tough coat protect them
from unfavourable condition
P1 Germination will only take place under favourable
condition
P2 The development of colourful and sweet tasting fruits
helps in the dispersal of seeds.
Or any suitable anwer [ Max 5 marks]

Bio Talk @SMK Maxwell

Another Talk...one after another...That's my usual routine in the middle of the year...year by year.... when most of the schools start organising Talk for SPM subjects. Teachers are concerned about their students achievement in SPM examination. So the counselors are searching for experience teachers or Excellent teachers to give tips and guidance as how to go about answering the examination questions with a target that majority of the students will score A in the subjects..(as in my case...BIOLOGY ! )

...and this morning.. I have completed my other task: delivering Talk @SMK Maxwell, my neighbouring school, a few yards away from seseri....

The audience was still BOYS..all boys.........with the same determination : To score A Biology..

To all SMK Maxwell boys : All the best for your Bio SPM examination..Score A as promised !

Bio Talk @ RMC

Have completed my Bio Talk @MTD a.k.a RMC..Focusing on Paper 3, the two hour talk seemed to be a bit too short for them. My audience wera all boys compared to my usual audience @seseri~ all girls !

..Be it boys or girls, my mission is very clear: to give the best tips as how to go about answering SPM Biology paper 2 and Paper 3...and of course within the two hours I have chosen the most important ones to be explained....and I need more timeeee.....

..Anyway..RMC boys are good, highly motivated and bright too...They asked questions and responded well to the Talk..I hope they will strive hard to score A+ Bio in their SPM....

..All the best to you ...Boys~ Doa from me to all of you~ Do Well and Do your best!

Malfunction of Cell Cycle

A respond to Farid of SEMASHUR:

WHAT ARE THE EFFECTS OF CELL CYCLE MALFUNCTION TO THE BODY ?

Cell reproduction is the leading cause of growth and developement in our bodies. This reproduction is caused by the cell cycle, which is defined as the life of a cell from its origin in the division of its parent cell until its own division into two.

The cell cycle goes through 5 main steps in order to reproduce: interphase, prophase, metaphase, anaphase, and telophase.
When prophase occurs, changes take place in the nucleus and cytoplasm. The cell is now prepared for anaphase, the following step, which is where the chromatid detach from one another and travel to opposite poles of the cell.

If a problem occurs in the cell cycle, and a malfunction in cell growth results, malignant tumors, also known as cancer may form.

The cell cycle is important for regulation of production of new, healthy cells in the body. If and when these cells stop dividing, ( they may do so at random points in the cycle or between phases ) , the cells usually have an irregular number of chromosomes, and if a tumor spreads through circulatory passage ways, it can cause harm or even death to the entire organism.

I hope it helps..