BIOL 121 | BIOL121 Module 3: Nutrition Updated
and Latest Questions and Correct Answers with
Rationale - Portage Learning
1. Which of the following describes the chemical structure of a triglyceride?
A. One glycerol molecule attached to three fatty acid chains
B. Two glycerol molecules attached to one fatty acid chain
C. A ring structure consisting of four fused carbon atoms
D. A phosphate group attached to a glycerol and two fatty acids
Correct Answer: A
Expert Explanation: Triglycerides are the most common form of lipids found in the human
body and food supply. They consist of a three-carbon glycerol backbone with three fatty
acids attached via ester bonds. During digestion, enzymes break these bonds to release
individual fatty acids for absorption. The length and saturation of these fatty acids
determine the physical properties of the fat. This structure serves as a major energy
reservoir in adipose tissue.
2. Saturated fatty acids are characterized by which of the following physical properties?
A. Being liquid at room temperature
B. Originating primarily from plant-based oils
C. Containing multiple double bonds in the carbon chain
D. Being solid at room temperature
Correct Answer: D
Expert Explanation: Saturated fatty acids contain no double bonds between the carbon
atoms in their hydrocarbon chain. This lack of double bonds allows the molecules to pack
tightly together in a straight formation. Consequently, these fats remain solid at room
temperature and are mostly found in animal products. Overconsumption of saturated fats
is often linked to higher levels of LDL cholesterol in the blood. Health organizations
recommend replacing them with unsaturated fats to improve cardiovascular health.
3. Which fatty acid is considered an essential nutrient that must be obtained from the diet?
A. Linoleic acid
B. Oleic acid
C. Stearic acid
D. Palmitic acid
,Correct Answer: A
Expert Explanation: Essential fatty acids are those that the human body cannot synthesize
because it lacks the necessary enzymes. Linoleic acid is an omega-6 fatty acid that serves as
a precursor to several important signaling molecules. It is vital for maintaining the
structural integrity of cell membranes throughout the body. Deficiency in these fats can
lead to poor wound healing and scaly skin conditions. Common dietary sources include
vegetable oils like sunflower, corn, and soybean oils.
4. What is the primary function of cholesterol in the human body?
A. Providing 9 calories per gram for immediate energy
B. Serving as a structural component of cell membranes and a precursor to hormones
C. Acting as a major component of muscle tissue
D. Transporting water-soluble vitamins through the blood
Correct Answer: B
Expert Explanation: Cholesterol is a sterol that plays a fundamental role in maintaining
the fluidity and stability of cell membranes. It acts as a necessary precursor for the
synthesis of bile acids, vitamin D, and steroid hormones like estrogen. Unlike triglycerides,
the body does not break down cholesterol for energy use. The liver is capable of
synthesizing enough cholesterol to meet the body’s physiological needs. Dietary cholesterol
is found exclusively in animal-based products such as eggs and meat.
5. How does bile facilitate the digestion of lipids in the small intestine?
A. Bile converts unsaturated fats into saturated fats for easier absorption
B. Bile chemically breaks down triglycerides into glycerol and fatty acids
C. Bile emulsifies large fat droplets into smaller micelles to increase surface area
D. Bile acts as a catalyst to speed up the action of lingual lipase
Correct Answer: C
Expert Explanation: Bile is produced by the liver and stored in the gallbladder until it is
needed for digestion. Its primary role is to act as an emulsifier, breaking down large fat
globules into smaller droplets. This process increases the total surface area available for
pancreatic lipase to perform chemical digestion. Without bile, fats would remain in large
clumps that are difficult for enzymes to penetrate. This mechanical action is essential for
the efficient absorption of fat-soluble vitamins and fatty acids.
6. Which enzyme is responsible for the majority of triglyceride digestion in the small
intestine?
A. Pancreatic lipase
B. Salivary amylase
, C. Gastric pepsin
D. Lipoprotein lipase
Correct Answer: A
Expert Explanation: Pancreatic lipase is the principal enzyme involved in the chemical
breakdown of dietary fats. It is secreted by the pancreas into the duodenum of the small
intestine in response to food. The enzyme targets the triglyceride molecules that have been
emulsified by bile salts. It cleaves two fatty acids from the glycerol backbone, leaving a
monoglyceride and two free fatty acids. These smaller components are then ready to be
packaged into micelles for transport into intestinal cells.
7. Which lipoprotein is responsible for transporting dietary lipids from the small intestine to
the rest of the body?
A. Chylomicron
B. LDL
C. VLDL
D. HDL
Correct Answer: A
Expert Explanation: Chylomicrons are large lipoprotein particles synthesized within the
intestinal cells following fat absorption. They primarily carry triglycerides, along with some
cholesterol and fat-soluble vitamins, into the lymphatic system. From the lymph, they
eventually enter the bloodstream to deliver lipids to various tissues like muscle and
adipose. As they travel through the blood, enzymes strip away the triglycerides for use or
storage. The remaining chylomicron remnants are eventually cleared and recycled by the
liver.
8. Which lipoprotein is commonly referred to as ‘bad cholesterol’ due to its role in plaque
formation?
A. VLDL
B. LDL
C. Chylomicron
D. HDL
Correct Answer: B
Expert Explanation: Low-density lipoprotein (LDL) is the primary carrier of cholesterol in
the blood to the body’s cells. When LDL levels are excessively high, they can lead to the
deposition of cholesterol in the arterial walls. This accumulation triggers an inflammatory
response that contributes to the formation of atherosclerotic plaque. Over time, these
and Latest Questions and Correct Answers with
Rationale - Portage Learning
1. Which of the following describes the chemical structure of a triglyceride?
A. One glycerol molecule attached to three fatty acid chains
B. Two glycerol molecules attached to one fatty acid chain
C. A ring structure consisting of four fused carbon atoms
D. A phosphate group attached to a glycerol and two fatty acids
Correct Answer: A
Expert Explanation: Triglycerides are the most common form of lipids found in the human
body and food supply. They consist of a three-carbon glycerol backbone with three fatty
acids attached via ester bonds. During digestion, enzymes break these bonds to release
individual fatty acids for absorption. The length and saturation of these fatty acids
determine the physical properties of the fat. This structure serves as a major energy
reservoir in adipose tissue.
2. Saturated fatty acids are characterized by which of the following physical properties?
A. Being liquid at room temperature
B. Originating primarily from plant-based oils
C. Containing multiple double bonds in the carbon chain
D. Being solid at room temperature
Correct Answer: D
Expert Explanation: Saturated fatty acids contain no double bonds between the carbon
atoms in their hydrocarbon chain. This lack of double bonds allows the molecules to pack
tightly together in a straight formation. Consequently, these fats remain solid at room
temperature and are mostly found in animal products. Overconsumption of saturated fats
is often linked to higher levels of LDL cholesterol in the blood. Health organizations
recommend replacing them with unsaturated fats to improve cardiovascular health.
3. Which fatty acid is considered an essential nutrient that must be obtained from the diet?
A. Linoleic acid
B. Oleic acid
C. Stearic acid
D. Palmitic acid
,Correct Answer: A
Expert Explanation: Essential fatty acids are those that the human body cannot synthesize
because it lacks the necessary enzymes. Linoleic acid is an omega-6 fatty acid that serves as
a precursor to several important signaling molecules. It is vital for maintaining the
structural integrity of cell membranes throughout the body. Deficiency in these fats can
lead to poor wound healing and scaly skin conditions. Common dietary sources include
vegetable oils like sunflower, corn, and soybean oils.
4. What is the primary function of cholesterol in the human body?
A. Providing 9 calories per gram for immediate energy
B. Serving as a structural component of cell membranes and a precursor to hormones
C. Acting as a major component of muscle tissue
D. Transporting water-soluble vitamins through the blood
Correct Answer: B
Expert Explanation: Cholesterol is a sterol that plays a fundamental role in maintaining
the fluidity and stability of cell membranes. It acts as a necessary precursor for the
synthesis of bile acids, vitamin D, and steroid hormones like estrogen. Unlike triglycerides,
the body does not break down cholesterol for energy use. The liver is capable of
synthesizing enough cholesterol to meet the body’s physiological needs. Dietary cholesterol
is found exclusively in animal-based products such as eggs and meat.
5. How does bile facilitate the digestion of lipids in the small intestine?
A. Bile converts unsaturated fats into saturated fats for easier absorption
B. Bile chemically breaks down triglycerides into glycerol and fatty acids
C. Bile emulsifies large fat droplets into smaller micelles to increase surface area
D. Bile acts as a catalyst to speed up the action of lingual lipase
Correct Answer: C
Expert Explanation: Bile is produced by the liver and stored in the gallbladder until it is
needed for digestion. Its primary role is to act as an emulsifier, breaking down large fat
globules into smaller droplets. This process increases the total surface area available for
pancreatic lipase to perform chemical digestion. Without bile, fats would remain in large
clumps that are difficult for enzymes to penetrate. This mechanical action is essential for
the efficient absorption of fat-soluble vitamins and fatty acids.
6. Which enzyme is responsible for the majority of triglyceride digestion in the small
intestine?
A. Pancreatic lipase
B. Salivary amylase
, C. Gastric pepsin
D. Lipoprotein lipase
Correct Answer: A
Expert Explanation: Pancreatic lipase is the principal enzyme involved in the chemical
breakdown of dietary fats. It is secreted by the pancreas into the duodenum of the small
intestine in response to food. The enzyme targets the triglyceride molecules that have been
emulsified by bile salts. It cleaves two fatty acids from the glycerol backbone, leaving a
monoglyceride and two free fatty acids. These smaller components are then ready to be
packaged into micelles for transport into intestinal cells.
7. Which lipoprotein is responsible for transporting dietary lipids from the small intestine to
the rest of the body?
A. Chylomicron
B. LDL
C. VLDL
D. HDL
Correct Answer: A
Expert Explanation: Chylomicrons are large lipoprotein particles synthesized within the
intestinal cells following fat absorption. They primarily carry triglycerides, along with some
cholesterol and fat-soluble vitamins, into the lymphatic system. From the lymph, they
eventually enter the bloodstream to deliver lipids to various tissues like muscle and
adipose. As they travel through the blood, enzymes strip away the triglycerides for use or
storage. The remaining chylomicron remnants are eventually cleared and recycled by the
liver.
8. Which lipoprotein is commonly referred to as ‘bad cholesterol’ due to its role in plaque
formation?
A. VLDL
B. LDL
C. Chylomicron
D. HDL
Correct Answer: B
Expert Explanation: Low-density lipoprotein (LDL) is the primary carrier of cholesterol in
the blood to the body’s cells. When LDL levels are excessively high, they can lead to the
deposition of cholesterol in the arterial walls. This accumulation triggers an inflammatory
response that contributes to the formation of atherosclerotic plaque. Over time, these
