BIOL 121 | BIOL121 Module 5: Nutrition Updated
and Latest Questions and Correct Answers with
Rationale - Portage Learning
1. Which water-soluble vitamin is primarily involved in the decarboxylation of pyruvate to
acetyl-CoA in the energy metabolism pathway?
A. Riboflavin
B. Niacin
C. Thiamin
D. Biotin
Correct Answer: C
Expert Explanation: Thiamin acts as the coenzyme thiamin pyrophosphate (TPP) which is
crucial for the conversion of pyruvate into acetyl-CoA. This step is essential for entering the
TCA cycle to generate ATP from carbohydrates. A deficiency in thiamin can lead to a
buildup of lactic acid and decreased energy production. Symptoms of deficiency include
fatigue and neurological issues known as Beriberi. Rich dietary sources include pork, whole
grains, and enriched cereals.
2. A patient presents with cracked corners of the mouth (cheilosis) and a smooth, purple-red
tongue (glossitis). Which vitamin deficiency is most likely?
A. Vitamin C
B. Vitamin B12
C. Riboflavin
D. Folate
Correct Answer: C
Expert Explanation: Riboflavin deficiency, also known as ariboflavinosis, specifically
targets the mucous membranes of the mouth and throat. The presence of cheilosis and
glossitis are classic clinical markers for this metabolic imbalance. Riboflavin functions as a
component of FAD and FMN coenzymes involved in oxidation-reduction reactions. Milk and
dairy products are the most significant sources of this vitamin in the American diet. Light
exposure can destroy riboflavin, which is why milk is often sold in opaque containers.
3. The ‘Four Ds’—dermatitis, diarrhea, dementia, and death—are classic symptoms of which
nutritional deficiency?
A. Beriberi (Thiamin)
B. Scurvy (Vitamin C)
,C. Pellagra (Niacin)
D. Pernicious Anemia (B12)
Correct Answer: C
Expert Explanation: Pellagra is the disease state resulting from a severe lack of niacin
(Vitamin B3) in the diet. The dermatitis associated with pellagra typically appears on skin
surfaces exposed to sunlight. Niacin is vital for the synthesis of NAD and NADP, which
handle hydrogen transport in metabolic pathways. Interestingly, the body can synthesize
niacin from the amino acid tryptophan if sufficient amounts are present. Common food
sources include meat, poultry, fish, and enriched grain products.
4. Vitamin C is essential for the synthesis of which structural protein found in connective
tissues?
A. Hemoglobin
B. Keratin
C. Collagen
D. Myosin
Correct Answer: C
Expert Explanation: Vitamin C facilitates the hydroxylation of proline and lysine, which
are necessary for stabilizing the collagen triple helix. Without this process, connective
tissues become weak, leading to the symptoms seen in scurvy. Collagen is the most
abundant protein in the body and provides structure to skin, bones, and tendons.
Furthermore, Vitamin C acts as a powerful antioxidant to protect these tissues from
oxidative damage. Citrus fruits and bell peppers are excellent sources for maintaining
adequate collagen integrity.
5. Which B-vitamin is uniquely required to prevent neural tube defects such as spina bifida
during early pregnancy?
A. Vitamin B6
B. Folate
C. Pantothenic Acid
D. Niacin
Correct Answer: B
Expert Explanation: Folate plays a critical role in DNA synthesis and the formation of new
cells, particularly during rapid growth. Adequate folate intake during the first few weeks of
pregnancy is vital for the proper closure of the neural tube. Because many pregnancies are
unplanned, the FDA mandates the fortification of grain products with folic acid. Folate
, deficiency can also lead to macrocytic anemia due to impaired red blood cell division. Leafy
green vegetables, legumes, and orange juice are natural sources of this nutrient.
6. A strict vegan is at the highest risk for a deficiency in which nutrient because it is found
almost exclusively in animal-derived foods?
A. Vitamin B12
B. Vitamin C
C. Thiamin
D. Biotin
Correct Answer: A
Expert Explanation: Vitamin B12 is produced by bacteria and is primarily accumulated in
the tissues of animals. Plant-based foods do not naturally contain B12 unless they are
fortified or contaminated with certain microorganisms. This vitamin is essential for myelin
sheath maintenance and the activation of folate for DNA synthesis. Vegans are encouraged
to consume fortified cereals, nutritional yeast, or supplements to avoid irreversible nerve
damage. The liver can store B12 for several years, so deficiency symptoms may take time to
manifest.
7. What is the primary physiological function of Pantothenic Acid in the body?
A. Visual pigment synthesis
B. Blood clotting
C. Calcium absorption
D. Part of Coenzyme A (CoA)
Correct Answer: D
Expert Explanation: Pantothenic acid is a structural component of Coenzyme A, which is
central to all energy-yielding pathways. It participates in the metabolism of carbohydrates,
lipids, and proteins by forming acetyl-CoA. Because it is found in almost all plant and
animal foods, a clinical deficiency is extremely rare. The name ‘pantothenic’ actually
derives from the Greek word ‘pantothen,’ meaning ‘from everywhere.’ It is also involved in
the synthesis of heme, cholesterol, and various hormones.
8. Eating large quantities of raw egg whites can lead to a deficiency of which vitamin due to
the presence of the protein avidin?
A. Niacin
B. Vitamin B6
C. Biotin
D. Folate
and Latest Questions and Correct Answers with
Rationale - Portage Learning
1. Which water-soluble vitamin is primarily involved in the decarboxylation of pyruvate to
acetyl-CoA in the energy metabolism pathway?
A. Riboflavin
B. Niacin
C. Thiamin
D. Biotin
Correct Answer: C
Expert Explanation: Thiamin acts as the coenzyme thiamin pyrophosphate (TPP) which is
crucial for the conversion of pyruvate into acetyl-CoA. This step is essential for entering the
TCA cycle to generate ATP from carbohydrates. A deficiency in thiamin can lead to a
buildup of lactic acid and decreased energy production. Symptoms of deficiency include
fatigue and neurological issues known as Beriberi. Rich dietary sources include pork, whole
grains, and enriched cereals.
2. A patient presents with cracked corners of the mouth (cheilosis) and a smooth, purple-red
tongue (glossitis). Which vitamin deficiency is most likely?
A. Vitamin C
B. Vitamin B12
C. Riboflavin
D. Folate
Correct Answer: C
Expert Explanation: Riboflavin deficiency, also known as ariboflavinosis, specifically
targets the mucous membranes of the mouth and throat. The presence of cheilosis and
glossitis are classic clinical markers for this metabolic imbalance. Riboflavin functions as a
component of FAD and FMN coenzymes involved in oxidation-reduction reactions. Milk and
dairy products are the most significant sources of this vitamin in the American diet. Light
exposure can destroy riboflavin, which is why milk is often sold in opaque containers.
3. The ‘Four Ds’—dermatitis, diarrhea, dementia, and death—are classic symptoms of which
nutritional deficiency?
A. Beriberi (Thiamin)
B. Scurvy (Vitamin C)
,C. Pellagra (Niacin)
D. Pernicious Anemia (B12)
Correct Answer: C
Expert Explanation: Pellagra is the disease state resulting from a severe lack of niacin
(Vitamin B3) in the diet. The dermatitis associated with pellagra typically appears on skin
surfaces exposed to sunlight. Niacin is vital for the synthesis of NAD and NADP, which
handle hydrogen transport in metabolic pathways. Interestingly, the body can synthesize
niacin from the amino acid tryptophan if sufficient amounts are present. Common food
sources include meat, poultry, fish, and enriched grain products.
4. Vitamin C is essential for the synthesis of which structural protein found in connective
tissues?
A. Hemoglobin
B. Keratin
C. Collagen
D. Myosin
Correct Answer: C
Expert Explanation: Vitamin C facilitates the hydroxylation of proline and lysine, which
are necessary for stabilizing the collagen triple helix. Without this process, connective
tissues become weak, leading to the symptoms seen in scurvy. Collagen is the most
abundant protein in the body and provides structure to skin, bones, and tendons.
Furthermore, Vitamin C acts as a powerful antioxidant to protect these tissues from
oxidative damage. Citrus fruits and bell peppers are excellent sources for maintaining
adequate collagen integrity.
5. Which B-vitamin is uniquely required to prevent neural tube defects such as spina bifida
during early pregnancy?
A. Vitamin B6
B. Folate
C. Pantothenic Acid
D. Niacin
Correct Answer: B
Expert Explanation: Folate plays a critical role in DNA synthesis and the formation of new
cells, particularly during rapid growth. Adequate folate intake during the first few weeks of
pregnancy is vital for the proper closure of the neural tube. Because many pregnancies are
unplanned, the FDA mandates the fortification of grain products with folic acid. Folate
, deficiency can also lead to macrocytic anemia due to impaired red blood cell division. Leafy
green vegetables, legumes, and orange juice are natural sources of this nutrient.
6. A strict vegan is at the highest risk for a deficiency in which nutrient because it is found
almost exclusively in animal-derived foods?
A. Vitamin B12
B. Vitamin C
C. Thiamin
D. Biotin
Correct Answer: A
Expert Explanation: Vitamin B12 is produced by bacteria and is primarily accumulated in
the tissues of animals. Plant-based foods do not naturally contain B12 unless they are
fortified or contaminated with certain microorganisms. This vitamin is essential for myelin
sheath maintenance and the activation of folate for DNA synthesis. Vegans are encouraged
to consume fortified cereals, nutritional yeast, or supplements to avoid irreversible nerve
damage. The liver can store B12 for several years, so deficiency symptoms may take time to
manifest.
7. What is the primary physiological function of Pantothenic Acid in the body?
A. Visual pigment synthesis
B. Blood clotting
C. Calcium absorption
D. Part of Coenzyme A (CoA)
Correct Answer: D
Expert Explanation: Pantothenic acid is a structural component of Coenzyme A, which is
central to all energy-yielding pathways. It participates in the metabolism of carbohydrates,
lipids, and proteins by forming acetyl-CoA. Because it is found in almost all plant and
animal foods, a clinical deficiency is extremely rare. The name ‘pantothenic’ actually
derives from the Greek word ‘pantothen,’ meaning ‘from everywhere.’ It is also involved in
the synthesis of heme, cholesterol, and various hormones.
8. Eating large quantities of raw egg whites can lead to a deficiency of which vitamin due to
the presence of the protein avidin?
A. Niacin
B. Vitamin B6
C. Biotin
D. Folate
