Question 1

Which experiment provided definitive evidence that DNA, not protein, is the genetic material in cells?

Accepted Answer

Hershey and Chase's experiment using radioactive sulfur and phosphorus

Question 2

In the Hershey and Chase experiment, why did radioactive phosphorus ($^{32}P$) end up inside the bacterial cells, but radioactive sulfur ($^{35}S$) did not?

Accepted Answer

DNA contains phosphorus, while proteins contain sulfur

Question 3

Which of the following correctly describes the structure of DNA as proposed by Watson and Crick?

Accepted Answer

DNA is a double helix with antiparallel strands held together by hydrogen bonds between complementary bases

Question 4

According to Chargaff's rules, if a DNA sample contains 30% adenine, what percentage of guanine would you expect?

Accepted Answer

20%

Question 5

Which bonds are responsible for holding the two strands of DNA together?

Accepted Answer

Hydrogen bonds

Question 6

What is the main difference between DNA replication in prokaryotes and eukaryotes?

Accepted Answer

Eukaryotes have multiple origins of replication, while prokaryotes have a single origin

Question 7

During DNA replication, which enzyme is responsible for unwinding the double helix?

Accepted Answer

Helicase

Question 8

Why are telomeres important in eukaryotic chromosomes?

Accepted Answer

They protect chromosome ends from degradation and limit the number of cell divisions

Question 9

Which of the following statements about RNA is correct?

Accepted Answer

RNA is usually single-stranded and contains ribose sugar

Question 10

What is the function of tRNA during translation?

Accepted Answer

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

Question 11

Which post-transcriptional modification protects mRNA from degradation in eukaryotes?

Accepted Answer

Addition of a poly-A tail and a GTP cap

Question 12

A mutation changes a codon from UAU (tyrosine) to UAA (stop). What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 13

Which process allows a single gene to code for multiple proteins in eukaryotes?

Accepted Answer

Alternative splicing

Question 14

What is the role of histone acetylation in gene regulation?

Accepted Answer

It loosens DNA binding, allowing transcription to occur

Question 15

Which of the following is true about the lac operon in prokaryotes?

Accepted Answer

It is an inducible operon that is turned on when lactose is present

Question 16

Which enzyme is responsible for connecting Okazaki fragments on the lagging strand during DNA replication?

Accepted Answer

Ligase

Question 17

A frameshift mutation is most likely to result from which of the following?

Accepted Answer

Insertion or deletion of a base

Question 18

Which of the following best explains why prokaryotes do not have telomeres?

Accepted Answer

Prokaryotes have circular chromosomes, so they do not lose DNA ends during replication

Question 19

Which of the following statements about gene regulation in prokaryotes and eukaryotes is correct?

Accepted Answer

Eukaryotes regulate individual genes at multiple levels, including epigenetic, transcriptional, and post-transcriptional

Gene Expression and Regulation: DNA Structure, Replication, and Protein Synthesis

Study Guide - Practice Questions

Study Guide - Flashcards