Question 1

Which of the following statements best describes the degeneracy of the genetic code?

Accepted Answer

Most amino acids are specified by more than one codon.

Question 2

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

Accepted Answer

An insertion or deletion of one or two nucleotides in the coding region.

Question 3

Which codon serves as the universal start codon for translation in most organisms?

Accepted Answer

$$AUG$$

Question 4

In the context of the wobble hypothesis, which position of the codon is least critical for accurate base pairing with the anticodon?

Accepted Answer

Third position (3' end of codon)

Question 5

Which of the following is a consequence of overlapping genes in a viral genome?

Accepted Answer

A single mRNA can be translated into multiple distinct polypeptides depending on the reading frame.

Question 6

Which enzyme is responsible for synthesizing RNA from a DNA template during transcription?

Accepted Answer

RNA polymerase

Question 7

A mutation changes a codon from $$UAC ($$tyrosine) to $$UAA. $$What type of mutation is this, and what is its likely effect?

Accepted Answer

Nonsense mutation; introduces a premature stop codon

Question 8

Which of the following statements about eukaryotic transcription is correct?

Accepted Answer

Transcription occurs in the nucleus and requires chromatin remodeling.

Question 9

What is the function of the 5' cap (7-methylguanosine) added to eukaryotic mRNA?

Accepted Answer

It facilitates ribosome binding and protects mRNA from degradation.

Question 10

Which of the following best explains why the genetic code is described as 'colinear'?

Accepted Answer

The order of codons in mRNA determines the order of amino acids in the protein.

Question 11

A scientist is studying a mitochondrial gene in humans and finds that the codon $$UGA$$ codes for tryptophan instead of serving as a stop codon. What does this observation illustrate?

Accepted Answer

Mitochondrial DNA can have exceptions to the universal genetic code.

Question 12

During splicing of eukaryotic pre-mRNA, which sequences are removed?

Accepted Answer

Introns

Question 13

Which of the following is a key difference between transcription in prokaryotes and eukaryotes?

Accepted Answer

Eukaryotic transcription requires chromatin remodeling and posttranscriptional processing.

Question 14

Which of the following best describes the function of enhancers in eukaryotic transcription?

Accepted Answer

They increase the efficiency or rate of transcription from a distance.

Question 15

A researcher observes that a single mRNA can be translated into two different proteins depending on which AUG codon is used as the start site. What genetic phenomenon does this illustrate?

Accepted Answer

Overlapping genes

Question 16

Which of the following is true regarding the triplet binding assay developed by Nirenberg and Leder?

Accepted Answer

It uses ribosomes to bind to single codons and charged tRNAs to identify specific codon assignments.

Question 17

Which of the following is NOT a feature of the genetic code?

Accepted Answer

It is ambiguous.

Question 18

Which of the following best describes RNA editing?

Accepted Answer

The addition or deletion of nucleotides or the alteration of nucleotide identities in RNA after transcription.

Question 19

If a gene contains the sequence $$5'	ext{TAC}\ 3' on $$the template strand, what will be the corresponding mRNA codon and the amino acid it encodes?

Accepted Answer

mRNA: $$5'	ext{AUG}\ 3'$$, Amino acid: Methionine

Question 20

Which of the following is a direct result of a nonsense mutation in a gene?

Accepted Answer

A truncated polypeptide due to premature translation termination

Chapter 13: The Genetic Code and Transcription – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards