BIOL 121 | BIOL121 Module 6: Nutrition Updated
and Latest Questions and Correct Answers with
Rationale - Portage Learning
1. Which fat-soluble vitamin is primarily responsible for the regeneration of rhodopsin, the
pigment required for vision in dim light?
A. Vitamin A
B. Vitamin D
C. Vitamin E
D. Vitamin K
Correct Answer: A
Expert Explanation: Vitamin A is essential for the visual cycle because it helps reform
rhodopsin in the rod cells of the retina. When light hits the eye, rhodopsin breaks down,
and vitamin A is required to regenerate it so vision can continue. A lack of available retinal
leads to the inability to see in low light, commonly known as night blindness. This function
highlights the critical role of retinoids in maintaining ocular health and functional vision.
Adequate intake of preformed vitamin A or carotenoids is necessary to prevent this
physiological impairment.
2. A deficiency of Vitamin D in children can lead to which of the following skeletal conditions
characterized by bowed legs?
A. Osteomalacia
B. Osteoporosis
C. Rickets
D. Scurvy
Correct Answer: C
Expert Explanation: Vitamin D is vital for the absorption of calcium and phosphorus
during the process of bone mineralization. In growing children, a chronic deficiency
prevents the skeletal system from hardening properly, leading to soft bones. This
condition, known as rickets, often manifests as a bowing of the legs due to the weight of the
body. While adults experience osteomalacia, rickets specifically refers to the deficiency
symptoms observed during the growth phase. Ensuring sufficient sunlight exposure or
dietary fortification is the primary method for preventing this condition.
3. Vitamin E serves as a primary antioxidant in the body. What is its specific mechanism of
action in protecting cell membranes?
A. It donates electrons to free radicals to stabilize them.
,B. It stimulates the production of white blood cells.
C. It increases the absorption of dietary calcium.
D. It facilitates the synthesis of prothrombin for clotting.
Correct Answer: A
Expert Explanation: Vitamin E acts as a chain-breaking antioxidant that protects
polyunsaturated fatty acids within cell membranes. It accomplishes this by donating an
electron to free radicals, thereby neutralizing their highly reactive nature. This prevention
of lipid peroxidation is crucial for maintaining the structural integrity of every cell in the
body. Once vitamin E is oxidized, it can be regenerated by other antioxidants like vitamin C.
Without this protection, cells would suffer significant oxidative damage, leading to
premature aging or disease.
4. Vitamin K is essential for the process of blood coagulation. Which protein’s synthesis is
directly dependent on Vitamin K?
A. Hemoglobin
B. Albumin
C. Prothrombin
D. Insulin
Correct Answer: C
Expert Explanation: Vitamin K acts as a coenzyme for the carboxylation of specific
glutamic acid residues in proteins involved in blood clotting. One of the most critical
proteins produced by the liver in this Vitamin K-dependent process is prothrombin.
Prothrombin is a precursor to thrombin, which eventually converts fibrinogen into fibrin to
form a blood clot. A deficiency in Vitamin K would lead to a failure in this metabolic
pathway, resulting in excessive bleeding. This demonstrates why Vitamin K is often
administered to patients before surgery or to newborns.
5. Which form of Vitamin A is found in plant-based foods like carrots and sweet potatoes and
can be converted to retinol in the body?
A. Retinyl ester
B. Beta-carotene
C. Retinoic acid
D. Cholecalciferol
Correct Answer: B
Expert Explanation: Beta-carotene is a provitamin A carotenoid that gives many fruits and
vegetables their vibrant orange and yellow colors. Unlike preformed Vitamin A found in
, animal products, beta-carotene must be cleaved in the small intestine to become active
retinol. The efficiency of this conversion depends on the body’s current vitamin A status
and the presence of dietary fat. It also serves as an antioxidant, independent of its role as a
precursor to Vitamin A. Consuming a variety of colorful vegetables ensures a steady supply
of this essential nutrient for the body.
6. Which of the following describes the toxicity risk associated with excessive Vitamin D
supplementation?
A. Night blindness
B. Hemorrhaging
C. Hypercalcemia
D. Erythrocyte hemolysis
Correct Answer: C
Expert Explanation: Excessive intake of Vitamin D through supplements can lead to a
condition known as hypercalcemia, or high blood calcium levels. Because Vitamin D
enhances calcium absorption, too much of it causes calcium to be pulled from bones and
deposited in soft tissues. This can result in the calcification of organs like the kidneys,
heart, and lungs, potentially causing permanent damage. Toxicity is almost never caused by
sun exposure or food alone, but rather by high-dose concentrated supplements. Monitoring
intake is vital to prevent the serious metabolic consequences of Vitamin D
overconsumption.
7. In premature infants, a deficiency of Vitamin E can result in which condition due to the
rupture of red blood cells?
A. Rickets
B. Osteomalacia
C. Xerophthalmia
D. Hemolytic anemia
Correct Answer: D
Expert Explanation: Vitamin E is critical for protecting the membranes of red blood cells
from oxidative damage caused by free radicals. Premature infants are particularly at risk
for deficiency because Vitamin E transfer from the mother occurs late in pregnancy. When
Vitamin E levels are insufficient, the red blood cell membranes become fragile and rupture
easily. This premature destruction of red blood cells is called hemolytic anemia, which
reduces the blood’s oxygen-carrying capacity. Supplementation or specialized infant
formulas are used to manage this risk in the neonatal intensive care unit.
and Latest Questions and Correct Answers with
Rationale - Portage Learning
1. Which fat-soluble vitamin is primarily responsible for the regeneration of rhodopsin, the
pigment required for vision in dim light?
A. Vitamin A
B. Vitamin D
C. Vitamin E
D. Vitamin K
Correct Answer: A
Expert Explanation: Vitamin A is essential for the visual cycle because it helps reform
rhodopsin in the rod cells of the retina. When light hits the eye, rhodopsin breaks down,
and vitamin A is required to regenerate it so vision can continue. A lack of available retinal
leads to the inability to see in low light, commonly known as night blindness. This function
highlights the critical role of retinoids in maintaining ocular health and functional vision.
Adequate intake of preformed vitamin A or carotenoids is necessary to prevent this
physiological impairment.
2. A deficiency of Vitamin D in children can lead to which of the following skeletal conditions
characterized by bowed legs?
A. Osteomalacia
B. Osteoporosis
C. Rickets
D. Scurvy
Correct Answer: C
Expert Explanation: Vitamin D is vital for the absorption of calcium and phosphorus
during the process of bone mineralization. In growing children, a chronic deficiency
prevents the skeletal system from hardening properly, leading to soft bones. This
condition, known as rickets, often manifests as a bowing of the legs due to the weight of the
body. While adults experience osteomalacia, rickets specifically refers to the deficiency
symptoms observed during the growth phase. Ensuring sufficient sunlight exposure or
dietary fortification is the primary method for preventing this condition.
3. Vitamin E serves as a primary antioxidant in the body. What is its specific mechanism of
action in protecting cell membranes?
A. It donates electrons to free radicals to stabilize them.
,B. It stimulates the production of white blood cells.
C. It increases the absorption of dietary calcium.
D. It facilitates the synthesis of prothrombin for clotting.
Correct Answer: A
Expert Explanation: Vitamin E acts as a chain-breaking antioxidant that protects
polyunsaturated fatty acids within cell membranes. It accomplishes this by donating an
electron to free radicals, thereby neutralizing their highly reactive nature. This prevention
of lipid peroxidation is crucial for maintaining the structural integrity of every cell in the
body. Once vitamin E is oxidized, it can be regenerated by other antioxidants like vitamin C.
Without this protection, cells would suffer significant oxidative damage, leading to
premature aging or disease.
4. Vitamin K is essential for the process of blood coagulation. Which protein’s synthesis is
directly dependent on Vitamin K?
A. Hemoglobin
B. Albumin
C. Prothrombin
D. Insulin
Correct Answer: C
Expert Explanation: Vitamin K acts as a coenzyme for the carboxylation of specific
glutamic acid residues in proteins involved in blood clotting. One of the most critical
proteins produced by the liver in this Vitamin K-dependent process is prothrombin.
Prothrombin is a precursor to thrombin, which eventually converts fibrinogen into fibrin to
form a blood clot. A deficiency in Vitamin K would lead to a failure in this metabolic
pathway, resulting in excessive bleeding. This demonstrates why Vitamin K is often
administered to patients before surgery or to newborns.
5. Which form of Vitamin A is found in plant-based foods like carrots and sweet potatoes and
can be converted to retinol in the body?
A. Retinyl ester
B. Beta-carotene
C. Retinoic acid
D. Cholecalciferol
Correct Answer: B
Expert Explanation: Beta-carotene is a provitamin A carotenoid that gives many fruits and
vegetables their vibrant orange and yellow colors. Unlike preformed Vitamin A found in
, animal products, beta-carotene must be cleaved in the small intestine to become active
retinol. The efficiency of this conversion depends on the body’s current vitamin A status
and the presence of dietary fat. It also serves as an antioxidant, independent of its role as a
precursor to Vitamin A. Consuming a variety of colorful vegetables ensures a steady supply
of this essential nutrient for the body.
6. Which of the following describes the toxicity risk associated with excessive Vitamin D
supplementation?
A. Night blindness
B. Hemorrhaging
C. Hypercalcemia
D. Erythrocyte hemolysis
Correct Answer: C
Expert Explanation: Excessive intake of Vitamin D through supplements can lead to a
condition known as hypercalcemia, or high blood calcium levels. Because Vitamin D
enhances calcium absorption, too much of it causes calcium to be pulled from bones and
deposited in soft tissues. This can result in the calcification of organs like the kidneys,
heart, and lungs, potentially causing permanent damage. Toxicity is almost never caused by
sun exposure or food alone, but rather by high-dose concentrated supplements. Monitoring
intake is vital to prevent the serious metabolic consequences of Vitamin D
overconsumption.
7. In premature infants, a deficiency of Vitamin E can result in which condition due to the
rupture of red blood cells?
A. Rickets
B. Osteomalacia
C. Xerophthalmia
D. Hemolytic anemia
Correct Answer: D
Expert Explanation: Vitamin E is critical for protecting the membranes of red blood cells
from oxidative damage caused by free radicals. Premature infants are particularly at risk
for deficiency because Vitamin E transfer from the mother occurs late in pregnancy. When
Vitamin E levels are insufficient, the red blood cell membranes become fragile and rupture
easily. This premature destruction of red blood cells is called hemolytic anemia, which
reduces the blood’s oxygen-carrying capacity. Supplementation or specialized infant
formulas are used to manage this risk in the neonatal intensive care unit.
