Question 1

Which of the following best describes the relationship between a gene and a trait, as illustrated in the 'From Gene to Trait' diagram?

Accepted Answer

A gene is a sequence of DNA that codes for a protein, which results in a physical trait.

Question 2

In the DNA double helix, which type of bond holds the two strands together between complementary bases?

Accepted Answer

Hydrogen bonds

Question 3

Referencing the DNA structure diagrams, what is the significance of the 5’ phosphate and 3’ hydroxyl ends in DNA replication?

Accepted Answer

DNA polymerase adds nucleotides to the free 3’ hydroxyl end, synthesizing DNA in the 5’ to 3’ direction.

Question 4

Which of the following best explains why DNA strands are described as antiparallel?

Accepted Answer

One strand runs 5’ to 3’ and the other runs 3’ to 5’.

Question 5

Based on the RNA structure diagram, which base is unique to RNA and replaces thymine found in DNA?

Accepted Answer

Uracil

Question 6

Which of the following best describes the process shown in the central dogma diagram (DNA → mRNA → Protein)?

Accepted Answer

Transcription followed by translation

Question 7

During transcription, which enzyme is responsible for synthesizing the RNA strand from the DNA template?

Accepted Answer

RNA polymerase

Question 8

In the translation process depicted, what is the role of tRNA?

Accepted Answer

It brings amino acids to the ribosome and matches them to the mRNA codon using its anticodon.

Question 9

Using the codon table, what amino acid is coded by the mRNA codon 5’–AUG–3’?

Accepted Answer

Methionine (Met)

Question 10

Which of the following best describes a missense mutation, as shown in the mutation diagrams?

Accepted Answer

A nucleotide change that results in a different amino acid being incorporated into the protein.

Question 11

What is the effect of an intercalating agent, as shown in the diagram with acridine orange?

Accepted Answer

It inserts between DNA bases, causing frameshift mutations.

Question 12

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

Accepted Answer

A truncated protein due to a premature stop codon.

Question 13

In the context of the lac operon diagrams, what happens when lactose is present and glucose is absent?

Accepted Answer

Allolactose binds to the repressor, inactivating it, and the operon is transcribed.

Question 14

Which of the following best explains why the genetic code is described as redundant, as seen in the codon table?

Accepted Answer

Multiple codons can code for the same amino acid, which helps protect against mutations.

Question 15

Which type of mutation is most likely to result from exposure to an alkylating agent, as shown in the methylguanine diagram?

Accepted Answer

Base substitution mutation

Question 16

In the context of the sickle cell anemia diagram, what type of mutation causes the change from glutamic acid to valine in hemoglobin?

Accepted Answer

Missense mutation

Question 17

Which DNA repair mechanism is specifically activated by light and repairs thymine dimers?

Accepted Answer

Photoreactivation

Question 18

Which of the following best describes the role of a repressor protein in the regulation of gene expression, as shown in the operon diagrams?

Accepted Answer

It binds to the operator to block transcription.

Question 19

Which of the following best describes the effect of a frameshift mutation, as shown in the mutation diagrams?

Accepted Answer

It alters the reading frame, potentially changing every amino acid downstream of the mutation.

Microbial Genetics: Structure, Expression, Regulation, and Mutation

Study Guide - Practice Questions