106
d) An essential for oxidative processes regulation
021. Which of the following statements concerning vitamin B1 functions are true:
a) An extremely important antioxidant, which protects cell membrane lipids from peroxidation by breaking the chain
reaction of free radical formation to which polyunsaturated fatty acids are particularly vulnerable
b) An essential coenzyme for oxidative decarboxylate of alpha-keto acids, most important being conversion of
pyruvate to acetyl coenzyme A
c) Specifically required for synthesis of prothrombin and several other clotting factors
d) Essential constituent of the flavoproteins, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD)
022. All of the following statements concerning vitamin B2 functions are true EXCEPT:
a) Essential constituent of flavoproteins, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD)
b) Plays key roles in hydrogen transfer reactions associated with glycolysis, TCA cycle and oxidative phosphorylation
c) An essential coenzyme for oxidative decarboxylate of alpha-keto acids, most important being conversion of
pyruvate to acetyl coenzyme A
d) Deficiency symptoms are cheilitis, cheilosis and angular stomatitis
023. Which of the following statements concerning vitamin PP (B3, niacin) functions are true:
a) Active group of the coenzymes nicotinamide-adenine dinucleotide (NAD) and nicotinamide-adenine
phosphate (NADP)
b) An essential coenzyme for oxidative decarboxylate of alpha-keto acids, most important being conversion of pyruvate to
acetyl coenzyme A
c) Specifically required for synthesis of prothrombin and several other clotting factors
d) Essential constituent of flavoproteins, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD)
024. Which of the following statements concerning pyridoxine (vitamin B6) functions are true:
a) Active functional form is pyridoxal phosphate, which is an essential coenzyme for transamination and
decarboxylation of amino acids in more than 50 different enzyme systems
b) Active group of the coenzymes nicotinamide-adenine dinucleotide (NAD) and nicotinamide-adenine phosphate
(NADP)
c) Essential constituent of flavoproteins, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD)
d) An extremely important antioxidant, which protects cell membrane lipids from peroxidation by breaking the chain
reaction of free radical formation to which polyunsaturated fatty acids are particularly vulnerable
025. Which of the following statements concerning pantothinic acid functions are true:
a) Active functional form is pyridoxal phosphate, which is an essential coenzyme for transamination and decarboxylation
of amino acids in more than 50 different enzyme systems
b) Essential constituent of coenzyme A, the important coenzyme for acyl transfer in the TCA cycle and de novo
fatty acid synthesis
c) An extremely important antioxidant, which protects cell membrane lipids from peroxidation by breaking the chain
reaction of free radical formation to which polyunsaturated fatty acids are particularly vulnerable
d) Coenzyme for several reactions involving CO
2
fixation into various compounds e.g. acetyl CoA to malonyl CoA (acetyl
CoA carboxylase) – initial step in de novo fatty acid synthesis; propionyl CoA to methylmalonyl CoA (propionyl CoA
carboxylase), pyruvate to oxaloacetate (pyruvate carboxylase)
026. Which of the following statements concerning biotin functions are true:
a) Active functional form is pyridoxal phosphate, which is an essential coenzyme for transamination and decarboxylation
of amino acids in more than 50 different enzyme systems
b) Essential constituent of coenzyme A, the important coenzyme for acyl transfer in the TCA cycle and de novo fatty acid
synthesis
c) An extremely important antioxidant, which protects cell membrane lipids from peroxidation by breaking the chain
reaction of free radical formation to which polyunsaturated fatty acids are particularly vulnerable
d) Coenzyme for several reactions involving CO
2
fixation into various compounds e.g. acetyl CoA to malonyl
CoA (acetyl CoA carboxylase) – initial step in de novo fatty acid synthesis; propionyl CoA to methylmalonyl
CoA (propionyl CoA carboxylase), pyruvate to oxaloacetate (pyruvate carboxylase)
027. Which of the following statements concerning vitamin B12 (cyanocobalamin) functions are true:
a) Active functional form is pyridoxal phosphate, which is an essential coenzyme for transamination and decarboxylation
of amino acids in more than 50 different enzyme systems
b) Essential constituent of coenzyme A, the important coenzyme for acyl transfer in the TCA cycle and de novo fatty acid
synthesis
c) Coenzyme for numerous metabolic reaction, including transformation of methylamlonyl CoA to succinyl CoA
in the metabolism of propionate; DNA synthesis (acts in concert with folic acid); transmethylation e.g.
methionine synthesis from homocysteine
d) An extremely important antioxidant, which protects cell membrane lipids from peroxidation by breaking the chain
reaction of free radical formation to which polyunsaturated fatty acids are particularly vulnerable
028. Which of the following statements concerning folic acid (folacin) functions are true:
a) Active functional form is pyridoxal phosphate, which is an essential coenzyme for transamination and decarboxylation
of amino acids in more than 50 different enzyme systems