The Importance of Organic compounds in the cell

Brief Account
1. Organic compounds:
-molecules contain carbon
-synthesised by the cell itself
-large molecules.
-carbohydrates (sugars and starch), proteins, lipids (fats) and nucleic acids (DNA and RNA)

2. Inorganic Compounds:
-Do not contain carbon
-simpler than organic compound
-can be found in cell, water, acids, alkalis and mineral salts

3. Should know at least two importance of :
Carbohydrates.
Proteins
Lipids(Fats)

4...And the Importance of water!

-as universal solvent, facilitate in cell reactions.
-as transport medium- blood plasma is almost 90% water
--as coolant-water absorbs excess heat from cells, evaporates and cools the cells.
-as an insulator- helps to maintain a narrow range of temperature change for biochemical reaction.
-as reactant- a substance used in a chemical reaction, in condensation and hydrolytic raction
-Gives structure and support- Forms hydrostatic skeleton in animals, gives mechanical support in plants.
-Medium for biochemical reactions- most of biochemical reactions occur when there is water. Enzymic reaction also require water.
-as lubrication- mucus and synovial fluid mainly consist of water, ease movement at joints..

5. You must know about carbohydrates and its classification

6.Starch, Glycogen and Cellulose are ALL polymer of GLUCOSE...Watch out for their differences in STRUCTURE and FUNCTION too....It could be asked in Paper 2...

7. Watch out for the difference between the process of CONDENSATION and HYDROLYSIS....
It involves WATER.

8. You must know about proteins and its structures,the formation and breakdown of dipeptides and polypeptides and its functions..

9. The differences between essential amino acid and non-essential amino acid..

10. You must know about Lipids, its types and functions

11. Oils refer to fats that are liquids at normal room temperature but Fats refer to fats that are solid at normal room temperature
11. The similarities and difference between saturated and unsaturated fats.

...And DNA - made up of nucleotides....The structure!!!!

Sample Questions for you to try:

1.Which of the following is not a function of water?
A. Provides a moist surface for diffusion of gases
B. Facilitates the movement of joints
C. An insulator of heat in the body
D. Facilitates the hydrolysis of food by enzymes

2. Haemoglobin is an example of a
A. primary structure of protein
B. secondary structure of protein
C. tertiary structure of protein
D. quarternary structure of protein

3. A dipeptide can be broken down into amino acids by the process of
A. condensation
B. heating
C. acid addition
D. hydrolysis
4. Plants usually store their excess carbohydrates in the form of
A. starch
B. glycogen
C. glucose
D. cellulose

5. What is the importance of nucleic acids?
A. Build cells during growth
B. Main source of energy
C. Required for the synthesis of antibodies
D. Carry genetic material

6. What is the composition of the basic unit of fats?
A. One molecule of fatty acid and three molecules of glycerol
B. One molecule of fatty acid and one molecule of glycerol
C. Three molecules of fatty acids and one molecule of glycerol
D. Three molecules of fatty acids

7. Which of these enzymes are synthesised in the human body?

I Trypsin
II Lipase
III Zymase
IV Cellulase

A I and II only C I, II and IV only
B II and III only D I, II, III and IV

8. Carbon is one of the essential elements in a cell. Its mainly found in
I water
II lipid
III amino acid
IV nucleic acid

A I and 11 only
B II and III only
C I, III and IV only
D II, III and IV only

Essay Question:
There are two important groups of compounds in cells, the organic compounds and the inorganic compounds. The organic compounds are protein, nucleic acids, carbohydrates and lipids. Describe the presence and importance of organic compounds, such as carbohydrates and proteins in a cells. (10 marks)

Suggested Answer:

Carbohydrate:
- It is a compound synthesized by plants through photosynthesis.
- It is involved in the building of plant cell wall.
- It is present in various forms including monosaccharide, disaccharide and polysaccharide.
- Polysaccharide is storage carbohydrate
- Example: glycogen is stored in animal cell and starch is stored in plant cell.
- Monosaccharide include glucose, galactose and fructose.
- They released energy when oxidized during respiration.
- Glucose is the main energy source for the cell.
- Lignin is dead cells of plants functions to give mechanical strength.

Protein:
- It is the main component of the cytoplasm and plasma membrane.
- Protein is present as keratin in hair and nail.
- Carrier protein in the plasma membrane function in the transport of substances across the plasma membrane.
- Enzymes, antibody and many hormones are proteins.
- Hormone function to regulate chemical process and cell metabolism, such as digestion.
- Enzyme act to catalyse metabolic reaction of the cell.
- Antobody defends the body from pathogenic attack.Protein also act as a source of energy during starvation.