Question

"Most microbes use carbohydrate (glucose) as the energy sources (via glycolysis, kreb's cycle, and electron transport chains). However, some microbes also use lipid or protein as the energy resources". Describe how energy (ATP) can be generated from the catabolism of: (a) Lipid (b) Protein .

Answer 1

Answer) Steps of catabolism of lipids are as follows :
* Firstly Triglycerides and phospholipids are broken down, and this is done by releasing fatty acid chains from the three-carbon glycerol backbone and this is catalyzed by lipases.
* The products of lipid catabolism, glycerol, and fatty acids are further degraded. Glycerol can be phosphorylated to glycerol-3-phosphate and easily converted to glyceraldehyde 3-phosphate, which continues through glycolysis.
* The released fatty acids are catabolized in a process called β-oxidation to produce NADH and FADH2, respectively, whose electrons can be used to make ATP by oxidative phosphorylation
* Then The acetyl groups produced during β-oxidation are carried by coenzyme A to the Krebs cycle and this results in their degradation to CO2, producing ATP by substrate-level phosphorylation and additional NADH and FADH2 molecules.

Steps of catabolism of protein are as follows:
* In protein catabolism the first step is breaking down of protein into amino acids and this is done by cleaving their peptide bonds ehich is also known as proteolysis.
* peptides can then be broken down further into individual amino acids by additional intracellular proteases, and each amino acid can be enzymatically deaminated to remove the amino group.
or we can say that amino acids are converted to sugars by Oxidative deamination.
* The amino group becomes ammonium as it is lost and later undergoes the urea cycle to become urea, in the liver. It is then released into the blood stream, where it is transferred to the kidneys, which will secrete the urea as urine
* the remaining acid will undergo either glycolysis or the TCA cycle to produce energy that the organism's body and this is done by transamination process
In glycolysis glucose (sugar) is broken down into 3 carbon compound called pyruvate and generates energy.