Question 1

Which experiment provided the first evidence that DNA, not protein, is the genetic material responsible for heredity in cells?

Accepted Answer

Avery, MacLeod, and McCarty's experiment

Question 2

In the Hershey-Chase experiment, which radioactive isotope was used to label DNA, and what was the key result?

Accepted Answer

Phosphorus-32; radioactivity entered the bacteria

Question 3

According to Chargaff’s rules, which equation correctly describes the relationship between nucleotide bases in double-stranded DNA?

Accepted Answer

$$A = T$$

Question 4

Which structural feature of DNA allows it to be easily separated during replication and transcription?

Accepted Answer

Hydrogen bonds between complementary bases

Question 5

What is the significance of the antiparallel orientation of DNA strands?

Accepted Answer

It enables complementary base pairing and proper replication

Question 6

During DNA replication, which enzyme is responsible for synthesizing short RNA primers?

Accepted Answer

Primase

Question 7

Why does the lagging strand of DNA require the formation of Okazaki fragments?

Accepted Answer

DNA polymerase can only synthesize DNA in the 5' to 3' direction, and the lagging strand template runs 5' to 3'

Question 8

Which equation best represents the semiconservative model of DNA replication?

Accepted Answer

Each daughter DNA molecule contains one old strand and one new strand

Question 9

What is the function of telomeres in eukaryotic chromosomes?

Accepted Answer

They protect coding regions from degradation during replication

Question 10

Which enzyme is responsible for lengthening telomeres during fetal development?

Accepted Answer

Telomerase

Question 11

Which process violates the central dogma of molecular biology by allowing RNA to be transcribed into DNA?

Accepted Answer

Reverse transcription in retroviruses

Question 12

During transcription, which DNA strand is used as the template for RNA synthesis?

Accepted Answer

The template (antisense) strand

Question 13

Which modification is added to the 5' end of eukaryotic mRNA during RNA processing?

Accepted Answer

GTP cap

Question 14

Alternative splicing allows a single gene to:

Accepted Answer

Code for multiple proteins with different functions

Question 15

Which equation represents the number of possible codons given four RNA bases?

Accepted Answer

$$4^3 = 64$

Question 16

What is the role of tRNA during translation?

Accepted Answer

It delivers specific amino acids to the ribosome

Question 17

Which codon acts as the start signal for translation in most organisms?

Accepted Answer

AUG

Question 18

How does the wobble effect protect against deleterious mutations?

Accepted Answer

It allows the third base of a codon to vary without changing the amino acid

Question 19

A missense mutation in the hemoglobin gene causes sickle cell anemia. Which change occurs at the molecular level?

Accepted Answer

Glutamic acid is replaced by valine due to a single nucleotide substitution

Question 20

Which mechanism is NOT a form of horizontal gene transfer in prokaryotes?

Accepted Answer

Mitosis

Gene Expression and Regulation: Foundations of Molecular Genetics

Study Guide - Practice Questions