Question 1

Which of the following is NOT one of the four major biomolecules found in the human body?

Accepted Answer

Steroid hormone

Question 2

Which property is shared by all biomolecules?

Accepted Answer

They all contain carbon

Question 3

Why are noncovalent interactions critical for the biological properties of biomolecules?

Accepted Answer

They allow for dynamic interactions and reversible binding

Question 4

Which biomolecule is present in the plasma membrane, cytosol, organelles, and cytoskeleton?

Accepted Answer

Protein

Question 5

Which of the following is an essential amino acid for humans?

Accepted Answer

Leucine

Question 6

What is the definition of a zwitterion?

Accepted Answer

A molecule with both positive and negative charges but overall neutral

Question 7

At a pH below the isoelectric point ($$pH \u003c pI$$), what is the overall charge of an amino acid?

Accepted Answer

Positive

Question 8

Which equation correctly represents the formation of a peptide bond between two amino acids?

Accepted Answer

$$\mathrm{Amino\ acid}_1 + \mathrm{Amino\ acid}_2 \rightarrow \mathrm{Dipeptide} + H_2O$$

Question 9

Which level of protein structure is primarily affected by denaturation?

Accepted Answer

Secondary, tertiary, and quaternary

Question 10

Phenylketonuria (PKU) is caused by a deficiency in which enzyme?

Accepted Answer

Phenylalanine hydroxylase

Question 11

Which of the following best describes the primary structure of a protein?

Accepted Answer

The sequence of amino acids joined by peptide bonds

Question 12

Which of the following is a function of proteins in the human body?

Accepted Answer

Catalyzing biochemical reactions

Question 13

Why are amino acids considered excellent buffers?

Accepted Answer

They can donate or accept protons due to their amino and carboxyl groups

Question 14

Which of the following statements about protein hydrolysis is correct?

Accepted Answer

It breaks peptide bonds, resulting in free amino acids

Question 15

A patient with PKU cannot convert phenylalanine to which amino acid?

Accepted Answer

Tyrosine

Question 16

Which of the following best explains why changes in body temperature can be detrimental to protein function?

Accepted Answer

High temperatures can disrupt noncovalent interactions, leading to denaturation

Question 17

Which of the following is a real-life example of a protein whose function is determined by its structure?

Accepted Answer

Hemoglobin, which carries oxygen due to its quaternary structure

Question 18

Which of the following best describes the difference between essential and non-essential amino acids?

Accepted Answer

Essential amino acids must be obtained from the diet; non-essential can be synthesized by the body

Question 19

Which of the following is true about the isoelectric point ($$pI) of an $$amino acid?

Accepted Answer

It is the pH at which the amino acid has no net charge

Question 20

Which of the following best describes the secondary structure of a protein?

Accepted Answer

Regular folding patterns such as alpha helices and beta sheets stabilized by hydrogen bonds

Amino Acids and Proteins: Structure, Properties, and Biological Roles

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