Question

Describe in general terms the steps organisms use to convert a carbon source and inorganic molecules into cells. Identify and describe the 6 principles that govern biosynthesis.

Answer 1

Answer:- Conversion of carbon source into the cell :- Generally cell convert three types of carbon source namely- carbohydrate, amino acid and lipid .

1.Carbohydrate are energy yeilding molecule , glucose is the main carbohydrates which is used by cell . In cell glucose is first break down into pyruvic acid through series of reaction of glycolytic pathway. Then pyruvate is converted into acetyl co enzyme A and enters in TCA cycle and it produces Carbon dioxide , NADH, QH2, GTP then last step of carbohydrate metabolism ended by entering oxidative phosphorelation and produces ATP . One molecule of glucose produces total 38 ATP .

2. Amino acid are converted to intermediate of citric acid cycle for eg. Pyruvate, acetyl co enzyme A, alpha keto gluterate , succinyl co enzyme A etc. First of all amino acid undergo deamination where removel of nitrogen from the amino acid take place and then alpha keto glutarate accept nitrogen and then produced glutamate. After that the nitrogen leaving carbon skeleton of amino acid yeilds intermediate of TCA cycle such as pyruvate and fumerate etc and excess nitrogen from glutamate is removed as a form of urea .

3. The third type of carbon source in cell is lipid , in our body this is generally found in triglycerides form which is degraded by lipases in intestine and by the action of bile and chylomicrons , these are converted into fatty acids and glycerol .Then fatty acids are converted into acetyl co enzyme A through series of reaction of beta oxidation of fatty acid which enter into TCA cycle to yeild energy. Glycerol enters in glycolytic pathway to produce pyruvate in the form of DHAP.

Six principles that govern biosynthesis are ---)

1. Principle of saving genetic storage , capacity and raw material:- According to this principle ...every large molecules are made from simple smaller molecule . To form macromolecules of our body simpler or micromolecules act as monomer which save genetic storage , raw material and capacity.

2. Principle of substrate evolution:- In order to synthesis of different biomolecule , the required substrate may be different but same enzyme may perform the necessary reaction which shows substrate evolution.

3. Principle of saving material and energy:- Same enzyme are used for dual purposes i.e both anabolic and catabolic process which is to save material and energy.

4.principle of permitting independent regulation:------ Though catabolic and anabolic reaction are opposite of each other yet same enzyme can be used for both purposes in different situations which seems independent regulation.

5. Principle of allowing pathways to operate simultaneously and independently for eg .in eukaryotic organism- both anabolic reaction and catabolic reaction occur simultaneously but in different Chambers or compartments.

6. Principle of driving ATP as a force to complete the biosynthetic reaction.