Question 1

Which of the following statements correctly describes a key difference between RNA and DNA?

Accepted Answer

RNA contains uracil instead of thymine.

Question 2

During mRNA splicing, what is the primary function of the spliceosome?

Accepted Answer

It removes introns and keeps exons.

Question 3

Which molecule acts as the adapter that translates a triplet codon to an amino acid during translation?

Accepted Answer

tRNA

Question 4

A ribosome must determine the correct reading frame on mRNA. What could be the consequence of using the wrong reading frame?

Accepted Answer

The amino acid sequence will be changed, potentially resulting in a nonfunctional protein.

Question 5

In prokaryotes, how does the ribosome determine where to start reading the mRNA?

Accepted Answer

By binding to the Shine-Dalgarno sequence.

Question 6

Which of the following is NOT a similarity between RNA and DNA?

Accepted Answer

Both contain ribose as their sugar.

Question 7

What is the function of rRNA in the ribosome?

Accepted Answer

It helps facilitate necessary ribosome assembly and function.

Question 8

Which of the following codons is a start codon, and what amino acid does it encode?

Accepted Answer

AUG; methionine

Question 9

How many possible codon combinations exist, and what is the minimum number of amino acids they encode for?

Accepted Answer

$$64$$ codons, encoding for over $$20$$ amino acids.

Question 10

What is the role of the 'wobble position' in tRNA?

Accepted Answer

It allows for an unusual base pair to occur, increasing codon recognition flexibility.

Question 11

Which of the following best describes the attachment between a codon and an anticodon?

Accepted Answer

It is a hydrogen bond that ensures the correct amino acid is added.

Question 12

Which process ensures that only exons are retained in mature mRNA?

Accepted Answer

Splicing

Question 13

If a mutation changes an amino acid codon to a stop codon, what is the likely result?

Accepted Answer

Translation will terminate prematurely, resulting in a truncated protein.

Question 14

Which of the following is a stop codon?

Accepted Answer

UAA

Question 15

In eukaryotes, how does the ribosome identify the start site for translation?

Accepted Answer

By binding to the 5' end of mRNA and scanning for the first AUG codon.

Question 16

Which statement about mRNA is correct?

Accepted Answer

It holds the sequence of nucleotides that determines which amino acids will be in the protein.

Question 17

Which of the following best explains why translation can be affected by a frameshift mutation?

Accepted Answer

Frameshift mutations change the reading frame, altering every amino acid downstream of the mutation.

Question 18

What is the minimum number of nucleotides required to code for a single amino acid?

Accepted Answer

$$3$$

Question 19

Which of the following is true about the synthesis direction of RNA?

Accepted Answer

RNA is synthesized in the 5' to 3' direction.

Question 20

A cell occasionally reads through a stop codon. What is the most likely outcome?

Accepted Answer

The cell will continue translation, potentially producing a longer, nonfunctional protein.

Ribosomes, RNA, and the Genetic Code: Key Concepts in Molecular Microbiology

Study Guide - Practice Questions