BIOD 121 Module 3 Exam Review | Proteins, Amino Acids & Body Functions | Exam Prep

BIOD 121 Module 3 Exam Review | Proteins, Amino Acids & Body
Functions | Exam Prep
150 Questions — Review Set




Question 1
Proteins are composed of which basic building blocks?
A. Fatty acids
✓ B. Amino acids
C. Monosaccharides
D. Nucleotides
Correct Answer: B. Amino acids
Feedback: Proteins are made up of chains of amino acids linked together.

Question 2
Which four elements are always found in amino acids?
✓ A. Carbon, hydrogen, oxygen, nitrogen
B. Carbon, hydrogen, oxygen, phosphorus
C. Carbon, nitrogen, sulfur, iron
D. Hydrogen, oxygen, calcium, sodium
Correct Answer: A. Carbon, hydrogen, oxygen, nitrogen
Feedback: Amino acids contain carbon, hydrogen, oxygen, and nitrogen; nitrogen distinguishes protein
from carbohydrate and fat.

Question 3
How many standard amino acids are commonly used to build human proteins?
A. 10
✓ B. 20
C. 30
D. 50
Correct Answer: B. 20
Feedback: There are 20 standard amino acids used to build proteins in the human body.

,Question 4
Essential amino acids are defined as those that:
A. The body can synthesize in adequate amounts
✓ B. Must be obtained from the diet because the body cannot make them in
sufficient amounts
C. Are never needed
D. Are only needed by infants
Correct Answer: B. Must be obtained from the diet because the body cannot make
them in sufficient amounts
Feedback: Essential amino acids cannot be synthesized by the body in adequate amounts and must
come from food.

Question 5
How many amino acids are considered essential for adult humans?
A. 5
✓ B. 9
C. 15
D. 20
Correct Answer: B. 9
Feedback: Nine amino acids are considered essential for adults and must be obtained through diet.

Question 6
Nonessential amino acids are those that:
A. Cannot be made by the body
✓ B. Can be synthesized by the body in adequate amounts
C. Are not part of proteins
D. Are toxic if consumed
Correct Answer: B. Can be synthesized by the body in adequate amounts
Feedback: Nonessential amino acids can be synthesized by the body and do not need to come directly
from food.

Question 7
Conditionally essential amino acids become essential under which circumstances?
A. Never
✓ B. During certain conditions like illness, stress, or infancy
C. Only in old age

, D. Only when eating a vegan diet
Correct Answer: B. During certain conditions like illness, stress, or infancy
Feedback: Conditionally essential amino acids are normally nonessential but become essential during
illness, stress, or rapid growth.

Question 8
Which is an example of a conditionally essential amino acid?
A. Leucine
✓ B. Glutamine
C. Lysine
D. Valine
Correct Answer: B. Glutamine
Feedback: Glutamine is considered conditionally essential, especially during illness, injury, or
metabolic stress.

Question 9
What structural feature links amino acids together in a protein chain?
A. Glycosidic bond
✓ B. Peptide bond
C. Ester bond
D. Hydrogen bond only
Correct Answer: B. Peptide bond
Feedback: Amino acids are linked together by peptide bonds formed between the amino and carboxyl
groups.

Question 10
A peptide bond forms between which two functional groups of amino acids?
✓ A. Amino group and carboxyl group
B. Two carboxyl groups
C. Two amino groups
D. Hydroxyl groups
Correct Answer: A. Amino group and carboxyl group
Feedback: A peptide bond forms through a condensation reaction between the amino group of one
amino acid and the carboxyl group of another.

Question 11
A dipeptide is formed from how many amino acids?

, A. One
✓ B. Two
C. Three
D. Ten or more
Correct Answer: B. Two
Feedback: A dipeptide consists of two amino acids joined by a single peptide bond.

Question 12
A polypeptide is best described as:
A. A single amino acid
✓ B. A chain of many amino acids linked by peptide bonds
C. A type of fat
D. A type of sugar
Correct Answer: B. A chain of many amino acids linked by peptide bonds
Feedback: A polypeptide is a long chain of many amino acids connected by peptide bonds.

Question 13
The primary structure of a protein refers to:
A. Its overall 3D shape
✓ B. The linear sequence of amino acids
C. Its function only
D. Its location in the cell
Correct Answer: B. The linear sequence of amino acids
Feedback: Primary structure is the specific linear sequence of amino acids in the polypeptide chain.

Question 14
The secondary structure of a protein refers to:
A. The amino acid sequence
✓ B. Local folding patterns like alpha helices and beta sheets
C. The protein's function
D. Post-translational modification
Correct Answer: B. Local folding patterns like alpha helices and beta sheets
Feedback: Secondary structure describes regular folding patterns, such as alpha helices and beta
pleated sheets, stabilized by hydrogen bonds.

Question 15