Question 1

Which type of mutation is most likely to result in a frameshift in the encoded protein sequence?

Accepted Answer

Insertion or deletion of a single nucleotide

Question 2

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

Accepted Answer

Nonsense mutation

Question 3

Which of the following best describes a silent mutation?

Accepted Answer

A mutation that does not change the amino acid sequence

Question 4

Given the mRNA sequence $$	ext{AUG UCU CGU ACC GGG ACU UAG}$$, a mutation changes it to $$	ext{AUG UCU CGU GAC CGG GAC UUA G}. $$What is the best description for this mutation?

Accepted Answer

Frameshift indel

Question 5

Which of the following is a consequence of a frameshift mutation?

Accepted Answer

All codons downstream of the mutation are altered

Question 6

What is the first amino acid incorporated during translation in prokaryotes?

Accepted Answer

N-formylmethionine (fMet)

Question 7

Which ribosomal RNA acts as a ribozyme to catalyze peptide bond formation during translation?

Accepted Answer

23S rRNA

Question 8

In eukaryotes, which feature increases the stability of mRNA compared to prokaryotes?

Accepted Answer

Poly(A) tail

Question 9

Which of the following is TRUE about translation in eukaryotes?

Accepted Answer

Ribosomes can be associated with the endoplasmic reticulum

Question 10

Arrange the following steps of prokaryotic translation in the correct order:
1. Initiator tRNA binds to the mRNA start codon in the P site
2. Large ribosomal subunit binds to the small subunit
3. Elongation factor helps with proofreading as charged tRNA enters the A site
4. Peptide bond is catalyzed by 23S rRNA
5. Elongation factor stimulates translocation of mRNA with respect to the ribosome

Accepted Answer

1, 2, 3, 4, 5

Question 11

A missense mutation in a gene results in which of the following?

Accepted Answer

A codon is changed to encode a different amino acid

Question 12

Which of the following is NOT a component required for translation in eukaryotes?

Accepted Answer

DNA polymerase

Question 13

A mutation changes the DNA sequence from ATG to ATA. What is the most likely effect?

Accepted Answer

Missense mutation

Question 14

Which of the following statements about ribosomes is TRUE?

Accepted Answer

Eukaryotic ribosomes are 80S and prokaryotic ribosomes are 70S

Question 15

Which of the following is a function of EF-Tu during translation?

Accepted Answer

Helps charged tRNA enter the A site and proofreads

Question 16

A mutation in the third position of a codon often results in which of the following?

Accepted Answer

Silent mutation due to wobble

Question 17

Which of the following is TRUE about the 5'-cap of eukaryotic mRNA?

Accepted Answer

It is essential for efficient initiation of translation

Question 18

Which of the following is a real-world consequence of a nonsense mutation in a gene encoding a critical enzyme?

Accepted Answer

The enzyme is truncated and likely nonfunctional

Question 19

During translation, what is the role of the anticodon on tRNA?

Accepted Answer

It pairs with the complementary codon on mRNA

Question 20

Which of the following best explains why transcription and translation are NOT coupled in eukaryotes?

Accepted Answer

Transcription occurs in the nucleus and translation occurs in the cytoplasm

Genetic Mutations: Indels and Point Mutations – OCT 29

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