Question 1

Which of the following best describes the backbone of a DNA molecule?

Accepted Answer

It is composed of alternating sugar (deoxyribose) and phosphate groups linked by phosphodiester bonds.

Question 2

If a DNA sample contains 35% cytosine, what percentage of adenine does it contain?

Accepted Answer

15%

Question 3

Which enzyme is primarily responsible for adding new nucleotides during DNA replication?

Accepted Answer

DNA polymerase

Question 4

During transcription, which region of the DNA is NOT transcribed?

Accepted Answer

Promoter region

Question 5

Which of the following statements about RNA and DNA is TRUE?

Accepted Answer

RNA contains ribose sugar, while DNA contains deoxyribose sugar.

Question 6

Which process involves the conversion of mRNA codons into a chain of amino acids?

Accepted Answer

Translation

Question 7

What is the function of tRNA during protein synthesis?

Accepted Answer

It brings specific amino acids to the ribosome by matching its anticodon to the mRNA codon.

Question 8

Which of the following is a post-transcriptional modification that occurs to eukaryotic mRNA before translation?

Accepted Answer

Addition of a 5' cap and a poly-A tail

Question 9

A mutation that changes a single nucleotide but does NOT alter the amino acid sequence of the protein is called:

Accepted Answer

Silent mutation

Question 10

Which base pairing is correct according to Chargaff's rules for DNA?

Accepted Answer

$$A = T$$

Question 11

Which of the following best describes the role of ribosomal RNA (rRNA) in translation?

Accepted Answer

It forms the core of the ribosome and catalyzes peptide bond formation.

Question 12

Which of the following is a consequence of a frameshift mutation?

Accepted Answer

It alters the reading frame, potentially changing every amino acid downstream of the mutation.

Question 13

Which of the following is TRUE about the hydrogen bonding in DNA?

Accepted Answer

Adenine pairs with thymine via two hydrogen bonds; guanine pairs with cytosine via three hydrogen bonds.

Question 14

Which of the following is NOT a function of proteins in the cell?

Accepted Answer

Storing genetic information

Question 15

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

Accepted Answer

The sequence of amino acids in the polypeptide chain

Question 16

Which process ensures that each new cell gets the same DNA as its parent cell?

Accepted Answer

DNA replication

Question 17

Which of the following is a difference between DNA and RNA?

Accepted Answer

DNA contains thymine, while RNA contains uracil.

Question 18

Which of the following is a real-world consequence of a nonsense mutation in a gene coding for hemoglobin?

Accepted Answer

It can result in a truncated, nonfunctional hemoglobin protein, potentially causing anemia.

Question 19

Which of the following best explains why multiple codons can code for the same amino acid?

Accepted Answer

The genetic code is redundant, meaning several codons can specify the same amino acid.

Question 20

Which of the following is TRUE regarding the tertiary structure of a protein?

Accepted Answer

It is determined by interactions among R groups, including hydrophobic interactions, ionic bonds, and disulfide bridges.

DNA Structure, Replication, Transcription, Translation, Protein Structure, and Mutations: Study Notes

Study Guide - Practice Questions