Question 1

A mutation changes a codon for tryptophan (UGG) into a stop codon (UGA). What type of mutation is this, and what is its likely effect on the protein product?

Accepted Answer

Nonsense mutation; results in premature termination of translation

Question 2

Which of the following best describes the function of the Shine-Dalgarno sequence in prokaryotic translation?

Accepted Answer

It aligns mRNA with the small ribosomal subunit for translation initiation

Question 3

A balanced translocation in a human karyotype can result in which of the following during meiosis?

Accepted Answer

Some gametes are unbalanced due to adjacent-1 segregation

Question 4

Which enzyme is responsible for filling the gap in DNA during base excision repair (BER) after the damaged base is removed?

Accepted Answer

DNA polymerase I

Question 5

A mutation in the TATA box of a eukaryotic gene is most likely to:

Accepted Answer

Prevent proper transcription initiation

Question 6

Which of the following is NOT typically repaired by base excision repair (BER)?

Accepted Answer

Thymine dimers

Question 7

During prokaryotic transcription, which event marks the termination phase?

Accepted Answer

Release factors bind and the RNA polymerase dissociates from DNA

Question 8

Which of the following statements about polycistronic mRNA in prokaryotes is TRUE?

Accepted Answer

It encodes several proteins in one transcript

Question 9

A frameshift mutation is most likely to result from:

Accepted Answer

Insertion or deletion of one or more bases not in multiples of three

Question 10

Which of the following is a physical mutagen that can cause DNA damage?

Accepted Answer

UV radiation

Question 11

What is the primary function of the 5' cap added to eukaryotic mRNA?

Accepted Answer

Facilitate mRNA export and ribosome binding

Question 12

Which process does NOT occur in prokaryotes?

Accepted Answer

Splicing of introns

Question 13

A mutation that introduces a premature stop codon is most likely to result in:

Accepted Answer

Loss of function of the protein

Question 14

Which of the following changes would most likely lead to loss of function in a protein?

Accepted Answer

Missense mutation changing a conserved residue

Question 15

Which repair mechanism uses UvrABC endonuclease to remove bulky DNA lesions such as thymine dimers?

Accepted Answer

Nucleotide excision repair

Question 16

During translation elongation, which of the following occurs?

Accepted Answer

Formation of peptide bonds

Question 17

Which enzyme catalyzes peptide bond formation during translation?

Accepted Answer

Peptidyl transferase

Question 18

A mutation in the start codon of a gene would most likely result in:

Accepted Answer

Failure to initiate translation

Question 19

Which of the following statements is TRUE for both paracentric and pericentric inversions?

Accepted Answer

Both lead to crossover suppression

Question 20

Which DNA polymerase in prokaryotes is primarily responsible for removing RNA primers and filling the gaps during DNA replication?

Accepted Answer

DNA polymerase I

Genetics Study Guide: DNA Replication, Transcription, Translation, Mutation, and Repair

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