Question 1

Which of the following statements best explains why all 20 standard amino acids found in proteins are called 'alpha-amino acids'?

Accepted Answer

Because the amino group is attached to the alpha carbon, which is the first carbon atom adjacent to the carboxyl group.

Question 2

Which of the following amino acids is classified as hydrophobic?

Accepted Answer

Leucine

Question 3

A protein is exposed to high heat and strong acid. Which of the following best describes what happens to the protein?

Accepted Answer

The protein denatures, losing its native structure and biological activity.

Question 4

Which of the following best describes the isoelectric point ($$pI) of an $$amino acid?

Accepted Answer

The $$pH at $$which the amino acid has no net electric charge.

Question 5

Which of the following is a correct description of the lock-and-key model of enzyme action?

Accepted Answer

The substrate fits exactly into the active site of the enzyme, like a key into a lock.

Question 6

Which of the following statements about enzyme cofactors is correct?

Accepted Answer

Metal ions and coenzymes are both types of enzyme cofactors.

Question 7

Which class of enzyme catalyzes the transfer of a phosphate group from ATP to a substrate?

Accepted Answer

Transferase

Question 8

Which of the following vitamins is lipid-soluble?

Accepted Answer

Vitamin A

Question 9

Which of the following best describes the difference between a nucleoside and a nucleotide?

Accepted Answer

A nucleotide contains a phosphate group, while a nucleoside does not.

Question 10

Which of the following base pairs is found in RNA but not in DNA?

Accepted Answer

Adenine–Uracil

Question 11

During DNA replication, which enzyme is responsible for synthesizing the new DNA strand?

Accepted Answer

DNA polymerase

Question 12

Which of the following statements about the genetic code is correct?

Accepted Answer

A codon is a sequence of three nucleotides that codes for an amino acid.

Question 13

Which of the following best describes the function of tRNA during translation?

Accepted Answer

It brings the correct amino acid to the ribosome and matches its anticodon to the mRNA codon.

Question 14

Which of the following is a correct statement about the human genome?

Accepted Answer

It contains about 3 billion base pairs in the haploid set.

Question 15

Which of the following best describes the polymerase chain reaction (PCR)?

Accepted Answer

A technique used to amplify a specific DNA sequence using repeated cycles of heating and cooling.

Question 16

Which of the following is a potential benefit of genetic engineering?

Accepted Answer

Production of insulin for diabetes treatment using recombinant DNA technology.

Question 17

Which of the following statements about CRISPR-Cas9 is correct?

Accepted Answer

Cas9 is an enzyme that cuts DNA at a specific sequence determined by a guide RNA.

Question 18

A patient is diagnosed with sickle-cell anemia. Which of the following best explains the molecular basis of this disease?

Accepted Answer

A point mutation in the gene for hemoglobin causes a single amino acid substitution.

Question 19

Which of the following best describes a SNP (single nucleotide polymorphism)?

Accepted Answer

A variation at a single base pair in the DNA sequence among individuals.

Question 20

Which of the following best explains why Okazaki fragments are formed during DNA replication?

Accepted Answer

DNA polymerase can only synthesize DNA in the 5' to 3' direction, so the lagging strand is synthesized discontinuously.

Chemistry of Life: Amino Acids, Proteins, Enzymes, Nucleic Acids, and Genomics (Chapters 18, 19, 26, 27)

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