Question 1

Which statement best describes the 'Central Dogma' of molecular biology?

Accepted Answer

It states that genetic information flows from DNA to RNA to protein.

Question 2

Given the following template DNA sequence: 3'-TAC GGA TCC-5', what is the corresponding mRNA sequence?

Accepted Answer

5'-AUG CCU AGG-3'

Question 3

If an mRNA strand is 900 nucleotides long, what is the maximum number of amino acids that could be coded by this mRNA?

Accepted Answer

$$\frac{900}{3} - 1 = 299$$

Question 4

Which enzyme is responsible for synthesizing RNA during transcription?

Accepted Answer

RNA polymerase

Question 5

During transcription, to which end of the growing RNA strand are new nucleotides added?

Accepted Answer

3' end

Question 6

Which of the following modifications occurs to eukaryotic pre-mRNA before it leaves the nucleus?

Accepted Answer

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

Question 7

What is the function of a spliceosome in eukaryotic cells?

Accepted Answer

It removes introns from pre-mRNA.

Question 8

Which molecule acts as a ribozyme during RNA processing?

Accepted Answer

snRNA within the spliceosome

Question 9

Which of the following best describes a polyribosome?

Accepted Answer

A group of ribosomes simultaneously translating the same mRNA molecule

Question 10

Which of the following is a key difference between DNA replication and transcription?

Accepted Answer

DNA replication requires a primer, but transcription does not.

Question 11

A point mutation changes a codon from GAG to GTG in the beta-globin gene. What is the consequence of this mutation in sickle-cell disease?

Accepted Answer

It causes a single amino acid substitution, changing glutamic acid to valine.

Question 12

Which of the following best explains why some point mutations are 'silent'?

Accepted Answer

They change a codon to another codon that codes for the same amino acid due to redundancy in the genetic code.

Question 13

Which of the following events occurs first during translation initiation in eukaryotes?

Accepted Answer

Small ribosomal subunit associates with mRNA

Question 14

What type of bond forms between the codon of mRNA and the anticodon of tRNA during translation?

Accepted Answer

Hydrogen bond

Question 15

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

Accepted Answer

It brings specific amino acids to the ribosome based on codon-anticodon pairing.

Question 16

A mutation that inserts or deletes a single nucleotide in a coding region is most likely to cause which of the following?

Accepted Answer

A frameshift mutation

Question 17

Which of the following is true regarding the redundancy of the genetic code?

Accepted Answer

Some amino acids are specified by more than one codon.

Question 18

Which of the following is an example of a ribozyme?

Accepted Answer

snRNA in the spliceosome and rRNA in the ribosome

Question 19

In prokaryotes, why can translation begin before transcription is complete?

Accepted Answer

Because both processes occur in the cytoplasm and mRNA is immediately accessible to ribosomes.

Question 20

Which of the following best describes the direction in which RNA polymerase reads the DNA template strand during transcription?

Accepted Answer

3' to 5'

Chapter 17: Gene Expression—REVIEW

Study Guide - Practice Questions