Question 1

Which experiment provided the first strong evidence that one gene encodes one enzyme, and what organism was primarily used in this research?

Accepted Answer

The Beadle and Tatum experiment using Neurospora crassa

Question 2

During transcription, which of the following best describes the function of the promoter region in a gene?

Accepted Answer

It is the DNA sequence where RNA polymerase binds to initiate transcription.

Question 3

Which of the following correctly compares transcription in prokaryotes and eukaryotes?

Accepted Answer

Eukaryotes require extensive RNA processing, including splicing, while prokaryotes generally do not.

Question 4

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

Accepted Answer

It facilitates ribosome binding and protects mRNA from degradation.

Question 5

Which of the following best describes the central dogma of molecular biology?

Accepted Answer

Genetic information flows from DNA to RNA to protein.

Question 6

A mutation changes a codon from $\mathrm{UAC}$ to $\mathrm{UAA}$. What type of mutation is this, and what is its likely effect on the protein?

Accepted Answer

Nonsense mutation; introduces a premature stop codon

Question 7

Which of the following statements about tRNA is correct?

Accepted Answer

tRNA carries amino acids to the ribosome and matches them to the mRNA codon via its anticodon.

Question 8

What is the main difference between a missense and a silent mutation?

Accepted Answer

A missense mutation changes an amino acid in the protein, while a silent mutation does not alter the amino acid sequence.

Question 9

Which of the following best describes the process of alternative RNA splicing?

Accepted Answer

It allows a single gene to code for multiple proteins by including or excluding different exons.

Question 10

A scientist is studying a protein that is only functional after a phosphate group is added to it. This modification is an example of:

Accepted Answer

Post-translational modification

Question 11

During translation, what is the role of the ribosome's A site?

Accepted Answer

It is where the tRNA carrying the next amino acid enters and base-pairs with the mRNA codon.

Question 12

Which of the following best explains how the CRISPR-Cas system can be used to edit genes?

Accepted Answer

It uses a protein to cut DNA at specific sequences guided by a complementary RNA molecule.

Question 13

A patient has a genetic disorder caused by a frameshift mutation. Which of the following is most likely to have caused this mutation?

Accepted Answer

An insertion or deletion of one or two nucleotides in the coding sequence

Question 14

Which of the following is true about the genetic code?

Accepted Answer

It is universal, with most organisms using the same codon assignments.

Question 15

A researcher finds that a protein is not being targeted to the endoplasmic reticulum (ER) as expected. Which signal is most likely missing from the protein?

Accepted Answer

A signal peptide sequence

Question 16

Which of the following best describes the process of translation initiation in eukaryotes?

Accepted Answer

The small ribosomal subunit binds to the 5' cap of mRNA and scans for the start codon.

Question 17

Which of the following is a real-world example of a disease caused by a point mutation?

Accepted Answer

Sickle cell anemia caused by a single nucleotide substitution in the $\beta$-globin gene

Question 18

Which of the following best explains why alternative RNA splicing is significant in eukaryotes?

Accepted Answer

It increases the number of different proteins that can be produced from a single gene.

Question 19

A mutation in the gene encoding RNA polymerase II would most directly affect which process?

Accepted Answer

Transcription of mRNA in eukaryotes

Question 20

Which of the following best describes a poly-A tail and its function?

Accepted Answer

A sequence of adenine nucleotides added to the 3' end of eukaryotic mRNA to increase stability and aid in export from the nucleus.

Chapter 17: The Genetic Code, Transcription, Translation, and DNA Mutations – Study Guide

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