Question 1

Which of the following best explains why genetically identical mice can display different phenotypes when raised in different environments?

Accepted Answer

Environmental factors interact with the genotype to influence phenotype.

Question 2

In Mendel’s experiments, what was the observed phenotypic ratio in the F2 generation for a monohybrid cross?

Accepted Answer

$$3:1$$

Question 3

Which statement about alleles is correct?

Accepted Answer

Alleles are variant forms of a gene that can arise from mutations in any part of the gene, including regulatory and coding sequences.

Question 4

A diploid individual can carry how many alleles for a given gene?

Accepted Answer

Two

Question 5

Which of the following is a misconception about mutations?

Accepted Answer

Gain-of-function mutations are always beneficial.

Question 6

What is the chemical structure that joins successive nucleotides in a DNA strand?

Accepted Answer

Phosphodiester bond

Question 7

Which of the following best describes the structure of B-form DNA?

Accepted Answer

It is a right-handed double helix with anti-parallel strands and complementary base pairing.

Question 8

If two genes are located on the same chromosome and are linked, which of Mendel’s laws does NOT apply?

Accepted Answer

Law of Independent Assortment

Question 9

Which experiment would best determine the degree of genetic contribution to a trait?

Accepted Answer

Raise genetically identical organisms in different environments and compare their phenotypes.

Question 10

Which of the following is true about the ABO blood type gene?

Accepted Answer

It has three alleles (A, B, O) and encodes a glycosyltransferase enzyme.

Question 11

What is the expected phenotypic ratio for a dihybrid cross involving two genes on different chromosomes according to Mendel’s second law?

Accepted Answer

$$9:3:3:1$$

Question 12

Which of the following mutations is most likely to result in a frameshift?

Accepted Answer

Insertion of one nucleotide

Question 13

Which of the following statements about dominant and recessive alleles is correct?

Accepted Answer

A dominant allele manifests its phenotype regardless of the other allele present.

Question 14

Which of the following best describes the role of major and minor grooves in DNA?

Accepted Answer

They contribute to the sequence specificity of DNA-binding proteins.

Question 15

Which of the following is a correct statement about the consequences of changes in DNA sequence?

Accepted Answer

A change in DNA sequence can alter protein amount, protein sequence, or protein function, leading to different phenotypes.

Question 16

Which of the following is true about the structure of a nucleotide in DNA?

Accepted Answer

It consists of a nitrogenous base, a deoxyribose sugar, and a phosphate group.

Question 17

Which of the following best explains why the B-form of DNA is most common under physiological conditions?

Accepted Answer

It is stabilized by hydrogen bonds and base stacking forces, and is right-handed.

Question 18

Which of the following is a real-world example of how mutations can affect viral evolution, as seen in COVID-19 variants?

Accepted Answer

Low replication fidelity in viruses leads to frequent mutations, some of which confer advantages and become dominant variants.

Question 19

Which of the following best describes codominance in the context of ABO blood types?

Accepted Answer

Both A and B alleles are expressed equally in the phenotype, resulting in type AB blood.

Genetics Study Guide: Language and Structure of DNA, Mendelian Inheritance, and Allelic Variation

Study Guide - Practice Questions