Question

please help me answere these questions

Lipids 61/where are fatty acids (FA) stored as an energy reserve 62/what is the difference between HDL and LDL cholesterol containing particles e 63/what is the fate of glycerol and the products when triacylglycerol is degraded 64/what are the three processes for complete oxidation of fatty acid to CO2 and H20 (producing energy) e 65/why is fatty acid degradation referred to as beta oxidation 66/what drives the reaction of acyl CoA synthetase 67/what is the function of carnitine 68/be able to identify the four recurring steps of FA degradation (oxidation, hydration, oxidation, thiolysis) and know that there are two carbons removed in each round 69/what is the net reaction of fatty acid degradation 70/how does citrate provide both electrons (NADH and NADPH) and carbon (acetyl CoA) 71/how is COzused in fatty acid synthesis - e e 72/acyl carrier protein requires what cofactor e 73/be able to identify the foar recurring steps of FA synthesis [condensation (synthesis), reduction, dehydration, reduction) 74/know that all of the enzymes for fatty acid synthesis are domains in one long polypeptide chain . product prostaglandin - 76/ what regulates fatty acid synthesis

Answer 1

61)

a) Fatty acids primarily stored as triglycerides in adipocytes of adipose tissue (Largest amount of Energy reservoir in body) Adipocytes are found subcutaneous tissue and mostly in the abdominal cavity. stored triacylglycerol should be is constantly hydrolyzed and resynthesized.

b) Secondly as glycogen in live and muscle.

62)Their is two major types of cholesterol: high-density lipoprotein (HDL) and low-density lipoprotein (LDL)

Difference between HDL and LDL

• The structural difference between HDL and LDL is their compositions of cholesterol and protein: HDL contain approx. 20% cholesterol and 50% protein while LDL contain 50% cholesterol and 25% protein
• HDL always consider as “good cholesterol”, it transports cholesterol to liver to excrete it out of body, while LDL considered as bad cholesterol, it carries cholesterol to arteries, where it may collect in artery walls, which can cause atherosclerosis.
• HDL helps the body to get rid of excess cholesterol so it’s less likely to end up in your arteries. And LDL accumulates in arteries walls which can increase the risk of blood clots in your arteries, and arise the risk of stroke heart attack.

63) The glycerol is absorbed by the liver, Phosphorylated and Glycerol 3-phosphate is oxidized into Dihydroxyacetone phosphate (DHAP), which is then isomerized into Glyceraldehyde 3- phosphate (G3P). G3P act as an intermediate in the glycolytic and gluconeogenic pathways and get converted into pyruvate or glucose.

64) Three process of complete oxidation of fatty acid:

1) β-oxidation -first fatty acid goes into the cytosol and then transfers to the mitochondria where β-oxidation takes place, β-oxidation involves activation to acyl-CoA by conjugation with coenzyme A in the cytosol.

2)generation of acetyl-CoA unit by β-oxidation , a molecule of FADH2 and a molecule of NADH + H+.

3)The acetyl-CoA then enters the mitochondrial tricarboxylic acid cycle (TCA) where it is oxidized to CO2 and H2O with the generation of additional FADH2 and NADH + H+.

65) Fatty acid degradation also known as β-oxidation because the beta carbon of the fatty acid undergoes oxidation to a carbonyl group and from the thioester carbon and The end product of cycle is the fatty acid shortened by 2 carbons and acetyl CoA.

66) acetyl CoA synthase formed by the two major molecule known as acetate and coenzyme A .

Reaction:

Acetate +ATP + CoA <=> Acetyl-CoA+ Pyrophosphate +AMP

67) Function of Carnitine:

• normal and altered fatty acid metabolism.
• buffering of the acyl coenzyme A (CoA)-CoA ratio
• branched-chain amino acid metabolism
• removal of excess acyl groups
• Peroxisomal fatty acid oxidation.

69) Net reaction of fatty acid degradation:

fatty acids degradation, generates acetyl-CoA, which is the entry molecule for the citric acid cycle

Fallowed by three major steps:

• Lipolysis of and release from adipose tissue
• Activation and transport into mitochondria
• β-oxidation
• Citric acid cycle

Product of TCA cycle is 6 NADH one H+ molecules, two FADH2 molecules, four carbon dioxide molecules, and two ATP molecules.

70) Acetyl CoA transfers its acetyl group to oxaloacetate to form citrate and begin the citric acid cycle and release of one carbon dioxide is coupled with the reduction of NAD⁺ to NADH in the citric acid cycle.

Citrate get converted into isocirate by losing one water molecule and isocitrate get oxidized into five-carbon molecule, α-ketoglutarate, together with Co2 and two electrons, which reduce NAD+ to NADH. This step is regulated by negative feedback from ATP and NADH.

71)Co2 used in fatty acid biosynthesis: this is two-step mechanism, Acetyl-CoA carboxylase (ACC) is a biotin-dependent enzyme that catalyzes the irreversible carboxylation of acetyl-CoA to produce malonyl-Co . The first reaction involves the ATP-dependent carboxylation of biotin with bicarbonate serving as the source of CO₂.while In second step, carboxyl group is transferred from biotin to acetyl CoA to form malonyl CoA.

72) Phosphopantetheine derived from Coenzyme A. is an essential prosthetic group of acyl carrier protein

73) step of fatty acid synthesis

1)Condensation: Claisen condensation reactions from acetyl-CoA and malonyl-CoA.

2) reduction: elongation the beta keto group is reduced to the fully saturated carbon chain by the sequential action of a ketoreductase, dehydratase, and enoyl reductase, followed by dehydration and reduction.

74) Fatty acid synthase (FAS) is an enzyme complex encoded by FASN gene. FAS It is not a single enzyme but a whole enzymatic system composed of two identical 272 kDa multifunctional polypeptides.

Fatty acid syntheses FAS can be divided into two groups on the basis of catalytic unit organization:

1. Type I FAS systems

2. Type II FAS systems

75)aspirin, ibuprofen and acetaminophen block by the block the cyclooxygenase 2 (COX-2) enzyme by mimicking prostaglandin.

76) regulation of fatty acid synthesis: Acetyl-CoA carboxylase is the point of regulation fatty acid synthesis, and is subject to both allosteric regulation and phosphorylation.