Question 1

Which of the water-soluble vitamins is able to be stored and retained in the body for long periods of time?

Accepted Answer

Vitamin B12 is unique among water-soluble vitamins as it can be stored in the liver for several years.

Question 2

PLP functions as a coenzyme for _____ when alanine enters the liver. Alanine becomes its α-keto acid, _____.

Accepted Answer

Alanine transaminase (ALT) catalyzes the transfer of an amino group from alanine to α-ketoglutarate, forming pyruvate and glutamate. PLP is a coenzyme for ALT.

Question 3

What amount of supplemental folic acid is recommended daily for women of childbearing age in the United States?

Accepted Answer

The recommended daily amount of supplemental folic acid for women of childbearing age in the United States is 400 micrograms (ug) of dietary folate equivalents (DFE) to help prevent neural tube defects in the developing fetus.

Question 4

Intrinsic factor is required for the majority of absorption of which vitamin?

Accepted Answer

Intrinsic factor is a protein produced by the stomach that is essential for the absorption of vitamin B₁₂ in the small intestine.

Question 5

Which of the following would you find under B₁₂-deficient conditions and the methyl trap hypothesis?

Accepted Answer

Under B12-deficient conditions, the methyl trap hypothesis suggests that 5-methyl THF accumulates because it cannot be converted back to THF due to the lack of B12, which is necessary for the conversion of homocysteine to methionine.

Question 6

364 53. Vitamin B₆ functions importantly in all of the following EXCEPT _____.

Accepted Answer

Vitamin B6 is not involved in the synthesis of fatty acids.

Question 7

A good source of vitamin B₆ is muscle meats because PLP is predominantly bound to the enzyme _____.

Accepted Answer

Glycogen phosphorylase is the enzyme to which PLP (pyridoxal phosphate), the active form of vitamin B6, is predominantly bound in muscle meats.

Question 8

Because vitamin B₆ is involved in heme synthesis, a deficiency symptom is

Accepted Answer

Vitamin B6 deficiency can lead to hypochromic, microcytic anemia due to its role in heme synthesis, which is essential for red blood cell production.

Question 9

The normal digestion and absorption of cobalamin requires adequate protein digestion in the stomach; the presence of 2 nonenzymatic proteins: _____; and a receptor located in the _____.

Accepted Answer

Cobalamin (vitamin B12) absorption requires R protein and intrinsic factor, and the receptor for absorption is located in the ileum.

Question 10

Which of the following vitamins has a Tolerable Upper Intake Level established?

Accepted Answer

Vitamin B6 has a Tolerable Upper Intake Level (UL) established due to potential adverse effects from excessive intake, unlike thiamin, riboflavin, and vitamin B12, which do not have a UL.

Question 11

Ascorbic acid can reduce the oxidized form of vitamin E. Choose the phrase that describes this.

Accepted Answer

Ascorbic acid reduces the tocopheroxy radical back to its active tocopherol form, and in the process, ascorbic acid is oxidized to semi-dehydroascorbate.

Question 12

B₆-dependent transamination reactions are important in which process?

Accepted Answer

The answer of B₆-dependent transamination reactions are important in which...

Question 13

Tetrahydrofolate is vitally important for dividing cells during growth and cancer and knowledge of this need is used in cancer treatment by giving the drug methotrexate to inhibit the enzyme _____.

Accepted Answer

Methotrexate inhibits the enzyme dihydrofolate reductase, which is necessary for the production of tetrahydrofolate. As tetrahydrofolate is vitally important for dividing cells during growth and cancer, inhibiting its production can help prevent the growth of cancer cells.

Question 14

Vitamin B₁₂ is absorbed in the _____.

Accepted Answer

Vitamin B₁₂, also known as thiamine or vitamin B1, is absorbed in the ileum. This is the last part of the small intestine before it joins with the colon. Thiamine is important for energy metabolism and neurological function, and a deficiency can lead to a serious condition known as beriberi.

Question 15

Metabolism of vitamin B₆ to the primary coenzyme form, pyridoxal phosphate, requires the action of what other B vitamin?

Accepted Answer

FMN (Flavin mononucleotide) is required for the conversion of vitamin B6 to its active coenzyme form, pyridoxal phosphate.

Question 16

Large amounts of folic acid can mask a vitamin B₁₂ deficiency and prevent _____ from resulting. Over time the symptoms unique to a vitamin B₁₂ deficiency will occur, and these are related to the _____.

Accepted Answer

Large amounts of folic acid can mask a vitamin B₁₂ deficiency and prevent macrocytic anemia from resulting. Over time, the symptoms unique to a vitamin B₁₂ deficiency will occur, and these are related to the nervous system.

Question 17

Which vitamin is most involved in amino acid metabolism?

Accepted Answer

Vitamin B6 is crucial for amino acid metabolism as it acts as a coenzyme in the transamination process, which is essential for the synthesis and breakdown of amino acids.

Question 18

Folate is vitally important for dividing cells during growth and cancer because of its essential role in the synthesis of _____.

Accepted Answer

Folate is required for the synthesis of purines and pyrimidines, which are the building blocks of DNA and RNA. Since cancer cells have a high rate of cell division, they require high levels of folate to support this growth. Without adequate folate, cancer cells cannot produce enough DNA and RNA, leading to impaired cell growth and division.

Quiz 9: Water-Soluble Vitamins

Which of the water-soluble vitamins is able to be stored and retained in the body for long periods of time?

PLP functions as a coenzyme for _ when alanine enters the liver. Alanine becomes its α-keto acid, _.

What amount of supplemental folic acid is recommended daily for women of childbearing age in the United States?

Intrinsic factor is required for the majority of absorption of which vitamin?

Which of the following would you find under B₁₂-deficient conditions and the methyl trap hypothesis?

364 53. Vitamin B₆ functions importantly in all of the following EXCEPT _____.

A good source of vitamin B₆ is muscle meats because PLP is predominantly bound to the enzyme _____.

Because vitamin B₆ is involved in heme synthesis, a deficiency symptom is

The normal digestion and absorption of cobalamin requires adequate protein digestion in the stomach; the presence of 2 nonenzymatic proteins: _; and a receptor located in the _.

Which of the following vitamins has a Tolerable Upper Intake Level established?

Ascorbic acid can reduce the oxidized form of vitamin E. Choose the phrase that describes this.

B₆-dependent transamination reactions are important in which process?

Tetrahydrofolate is vitally important for dividing cells during growth and cancer and knowledge of this need is used in cancer treatment by giving the drug methotrexate to inhibit the enzyme _____.

Vitamin B₁₂ is absorbed in the _____.

Metabolism of vitamin B₆ to the primary coenzyme form, pyridoxal phosphate, requires the action of what other B vitamin?

Large amounts of folic acid can mask a vitamin B₁₂ deficiency and prevent _ from resulting. Over time the symptoms unique to a vitamin B₁₂ deficiency will occur, and these are related to the _.

Which vitamin is most involved in amino acid metabolism?

Folate is vitally important for dividing cells during growth and cancer because of its essential role in the synthesis of _____.

Quiz 9: Water-Soluble Vitamins

Which of the water-soluble vitamins is able to be stored and retained in the body for long periods of time?

PLP functions as a coenzyme for _____ when alanine enters the liver. Alanine becomes its α-keto acid, _____.

What amount of supplemental folic acid is recommended daily for women of childbearing age in the United States?

Intrinsic factor is required for the majority of absorption of which vitamin?

Which of the following would you find under B12-deficient conditions and the methyl trap hypothesis?

364 53. Vitamin B6 functions importantly in all of the following EXCEPT _____.

A good source of vitamin B6 is muscle meats because PLP is predominantly bound to the enzyme _____.

Because vitamin B6 is involved in heme synthesis, a deficiency symptom is

The normal digestion and absorption of cobalamin requires adequate protein digestion in the stomach; the presence of 2 nonenzymatic proteins: _____; and a receptor located in the _____.

Which of the following vitamins has a Tolerable Upper Intake Level established?

Ascorbic acid can reduce the oxidized form of vitamin E. Choose the phrase that describes this.

B6-dependent transamination reactions are important in which process?

Tetrahydrofolate is vitally important for dividing cells during growth and cancer and knowledge of this need is used in cancer treatment by giving the drug methotrexate to inhibit the enzyme _____.

Vitamin B12 is absorbed in the _____.

Metabolism of vitamin B6 to the primary coenzyme form, pyridoxal phosphate, requires the action of what other B vitamin?

Large amounts of folic acid can mask a vitamin B12 deficiency and prevent _____ from resulting. Over time the symptoms unique to a vitamin B12 deficiency will occur, and these are related to the _____.

Which vitamin is most involved in amino acid metabolism?

Folate is vitally important for dividing cells during growth and cancer because of its essential role in the synthesis of _____.

PLP functions as a coenzyme for _ when alanine enters the liver. Alanine becomes its α-keto acid, _.

Which of the following would you find under B₁₂-deficient conditions and the methyl trap hypothesis?

364 53. Vitamin B₆ functions importantly in all of the following EXCEPT _____.

A good source of vitamin B₆ is muscle meats because PLP is predominantly bound to the enzyme _____.

Because vitamin B₆ is involved in heme synthesis, a deficiency symptom is

The normal digestion and absorption of cobalamin requires adequate protein digestion in the stomach; the presence of 2 nonenzymatic proteins: _; and a receptor located in the _.

B₆-dependent transamination reactions are important in which process?

Vitamin B₁₂ is absorbed in the _____.

Metabolism of vitamin B₆ to the primary coenzyme form, pyridoxal phosphate, requires the action of what other B vitamin?

Large amounts of folic acid can mask a vitamin B₁₂ deficiency and prevent _ from resulting. Over time the symptoms unique to a vitamin B₁₂ deficiency will occur, and these are related to the _.