Biochemistry LE 4: Vitamins, Minerals, and Trace Elements

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What is the relationship between thiamine requirement and carbohydrate intake?

Thiamine requirement remains constant with carbohydrate intake

Thiamine requirement increases as carbohydrate intake increases (correct)

Thiamine requirement is independent of carbohydrate intake

Thiamine requirement decreases as carbohydrate intake increases

What is the function of TPP in the TCA cycle?

To convert isocitrate to α-Ketoglutarate

To convert α-Ketoglutarate to Succinyl-CoA

To convert pyruvate to acetyl-CoA

All of the above (correct)

What is the consequence of reduced α-Ketoglutarate dehydrogenase activity?

No effect on oxidative decarboxylation of α-keto acids

Variable effect on oxidative decarboxylation of α-keto acids

Increased oxidative decarboxylation of α-keto acids

Reduced oxidative decarboxylation of α-keto acids (correct)

What is the result of decreased Thiamine Pyrophosphate?

Decreased ATP synthesis Signup and view all the answers

What is the consequence of impaired conversion of pyruvate to acetyl-CoA?

Increased production of lactate/pyruvate Signup and view all the answers

What is the role of RBC transketolase in measuring thiamine status?

To measure thiamine status in the body Signup and view all the answers

What is the coenzyme required for pyruvate dehydrogenase and α-Ketoglutarate dehydrogenase?

Thiamine Pyrophosphate Signup and view all the answers

What is the consequence of thiamine deficiency in individuals on a high-carbohydrate diet?

Increased production of lactate/pyruvate Signup and view all the answers

What is the role of TPP in the catabolism of branched-chain amino acids?

Involved in the catabolism of branched-chain amino acids Signup and view all the answers

What is the main component of riboflavin?

Ribitol Signup and view all the answers

What is the role of FMN and FAD in redox reactions?

They accept hydrogen atoms Signup and view all the answers

What is the result of riboflavin deficiency?

A decrease in ATP production Signup and view all the answers

What is the byproduct of FMN and FAD accepting hydrogen atoms?

FMNH2 and FADH2 Signup and view all the answers

What is the role of FAD in the Citric Acid Cycle?

Conversion of Succinate to Fumarate Signup and view all the answers

What is the role of FAD in the B-Oxidation of fatty acids?

Participation in redox reactions Signup and view all the answers

What is the biologically active form of riboflavin?

FMN and FAD Signup and view all the answers

What is the function of flavoenzymes?

To act as coenzymes with riboflavin Signup and view all the answers

What is the role of riboflavin in energy production?

To participate in redox reactions essential for energy production Signup and view all the answers

What is the primary function of sphingomyelin in the CNS?

To form myelin sheaths Signup and view all the answers

What is the precursor of heme that is affected by a deficiency in PLP?

Aminolevulinic acid Signup and view all the answers

What is the result of iron accumulation in erythroblasts in the bone marrow?

Sideroblastic anemia Signup and view all the answers

What is the consequence of a vitamin B6 deficiency on homocysteine?

Homocysteine builds up in the blood Signup and view all the answers

What is the effect of isoniazid on vitamin B6?

It forms an inactive hydrazone derivative with vitamin B6 Signup and view all the answers

Why are people who take oral contraceptive pills advised to increase their vitamin B6 intake?

To compensate for the increased requirement of vitamin B6 Signup and view all the answers

What is the consequence of a deficiency in vitamin B6 on heme synthesis?

Heme synthesis is inhibited Signup and view all the answers

What is the relationship between homocysteine and cardiovascular diseases?

Homocysteine increases the risk of cardiovascular diseases Signup and view all the answers

What is the function of vitamin B6 in cysteine synthesis?

To convert homocysteine to cysteine Signup and view all the answers

What is the role of folates in DNA synthesis?

To produce dTMP and purine rings Signup and view all the answers

What is the result of combined deficiency of Vitamins B9 and B12?

Macrocytic, megaloblastic anemia Signup and view all the answers

What happens to cells during folate deficiency?

They are arrested in the S phase of cell division Signup and view all the answers

What is the characteristic of red blood cell precursors in macrocytic, megaloblastic anemia?

They are large and immature Signup and view all the answers

Why do patients with macrocytic, megaloblastic anemia get anemia?

Due to the destruction of red blood cells Signup and view all the answers

What is the effect of folate deficiency on DNA synthesis?

It is inhibited Signup and view all the answers

Which groups of people are at risk of folate deficiency due to impaired absorption?

Alcoholics and elderly population Signup and view all the answers

What is the effect of certain drugs on folate availability?

They decrease the absorption of folic acid Signup and view all the answers

Why may a person have a relative deficiency of folate during pregnancy?

Due to increased demand for DNA synthesis Signup and view all the answers

What is the mechanism of action of sulfonamides on bacteria?

Inhibit the formation of folic acid by replacing PABA Signup and view all the answers

What is the effect of sulfonamides on bacterial growth?

Growth and proliferation are inhibited Signup and view all the answers

What is the function of trimethoprim?

Inhibit bacterial dihydrofolate reductase Signup and view all the answers

What is the effect of trimethoprim on bacterial growth?

Bacteria die Signup and view all the answers

What is the combination of sulfamethoxazole and trimethoprim commonly used for?

Treating urinary tract infections Signup and view all the answers

What is unique about the structure of cobalamin?

It has a cobalt atom in the center Signup and view all the answers

Who is at risk for vitamin B12 deficiency?

Vegans and people with malabsorption problems Signup and view all the answers

What is required for the conversion of homocysteine to methionine?

Folate and vitamin B12 Signup and view all the answers

What is the role of methionine in the synthesis of SAM?

It is a precursor of SAM Signup and view all the answers