Question 1

Which of the following best describes the Central Dogma of molecular biology?

Accepted Answer

DNA \rightarrow mRNA \rightarrow protein

Question 2

Why is the genetic code considered 'degenerate'?

Accepted Answer

Some amino acids are coded by more than one codon

Question 3

If a single nucleotide is inserted into a coding sequence, what is the most likely result?

Accepted Answer

A frameshift mutation, altering the reading frame

Question 4

Which enzyme is responsible for synthesizing mRNA from a DNA template during transcription in bacteria?

Accepted Answer

RNA polymerase

Question 5

What is the function of the sigma factor in bacterial transcription?

Accepted Answer

It recognizes and binds to the promoter region of DNA

Question 6

Which of the following codons is the universal start codon for translation?

Accepted Answer

AUG

Question 7

A frameshift mutation can be reversed by which of the following?

Accepted Answer

Inserting two nucleotides after the original insertion, restoring the reading frame (total of three)

Question 8

Which of the following is NOT a component of the mature eukaryotic mRNA?

Accepted Answer

Introns

Question 9

What is the role of the spliceosome in eukaryotic cells?

Accepted Answer

It removes introns from pre-mRNA

Question 10

Which of the following statements about codons is TRUE?

Accepted Answer

Each codon is unambiguous and codes for only one amino acid

Question 11

If the DNA template strand is 3'-TACCGTAACTCG-5', what is the corresponding mRNA sequence?

Accepted Answer

5'-AUGGCAUUGAGC-3'

Question 12

Which of the following best explains why only 30 different tRNAs are needed to recognize 61 codons?

Accepted Answer

The wobble hypothesis allows flexibility in the third base pairing

Question 13

Which of the following is a stop codon?

Accepted Answer

UAA

Question 14

What is the effect of a nonsense mutation in a coding region?

Accepted Answer

It introduces a premature stop codon

Question 15

Which of the following is TRUE about the directionality of mRNA and protein synthesis?

Accepted Answer

mRNA and protein sequences are colinear, both synthesized from 5' to 3'

Question 16

Which of the following is a key difference between bacterial and eukaryotic transcription?

Accepted Answer

Bacteria use sigma factors, while eukaryotes use basal transcription factors

Question 17

Which of the following best describes the function of polynucleotide phosphorylase in early genetic code experiments?

Accepted Answer

It links ribonucleoside diphosphates into mRNA without a DNA template

Question 18

In the triplet binding assay, what is the purpose of using a radiolabeled amino acid attached to tRNA?

Accepted Answer

To identify which codon codes for which amino acid

Question 19

Which of the following modifications is added to the 5' end of eukaryotic mRNA?

Accepted Answer

5' cap

Genetic Code and Transcription: Structure, Function, and Mechanisms

Study Guide - Practice Questions