Question 1

Which of the following best describes the main function of CRISPR-Cas systems in bacteria?

Accepted Answer

They serve as an adaptive immune system that targets and destroys invading viral DNA.

Question 2

A researcher is using a model organism to study a human genetic disease caused by a defect in DNA repair. Which organism would be most appropriate for rapid genetic analysis and why?

Accepted Answer

Escherichia coli, because it divides rapidly and shares conserved DNA repair pathways with humans.

Question 3

During which phase of the cell cycle does DNA replication occur?

Accepted Answer

S phase

Question 4

Which of the following statements about Mendel’s law of independent assortment is correct?

Accepted Answer

Genes located on different chromosomes assort independently during gamete formation.

Question 5

A diploid organism has a chromosome number of 2n = 8. How many genetically distinct gametes can it produce by independent assortment alone?

Accepted Answer

$$2^4 = 16$

Question 6

Which of the following best explains why sickle-cell anemia is considered a molecular disease?

Accepted Answer

It is caused by a single nucleotide change in the DNA sequence of the $$\beta-$$globin gene, resulting in an altered amino acid in the protein.

Question 7

Which of the following is a direct application of recombinant DNA technology in medicine?

Accepted Answer

Production of human insulin in bacteria for diabetes treatment.

Question 8

A plant with genotype $$AaBb is $$testcrossed with $$aabb. $$What is the expected phenotypic ratio among the offspring if the genes assort independently?

Accepted Answer

1:1:1:1

Question 9

Which of the following best describes the role of model organisms in genetics research?

Accepted Answer

They allow researchers to study fundamental biological processes that are conserved across species, including humans.

Question 10

Which of the following is a key ethical concern raised by the use of CRISPR-Cas genome editing in humans?

Accepted Answer

Potential unintended genetic changes that could be passed to future generations.

Question 11

A scientist observes that a certain genetic disorder is more common in children born to older mothers. Which chromosomal event is most likely responsible for this observation?

Accepted Answer

Nondisjunction during meiosis

Question 12

Which of the following best describes the difference between mitosis and meiosis?

Accepted Answer

Mitosis produces two genetically identical diploid cells, while meiosis produces four genetically distinct haploid cells.

Question 13

Which of the following is a real-world application of the Hardy–Weinberg law in population genetics?

Accepted Answer

Estimating carrier frequencies for genetic diseases in human populations.

Question 14

Which of the following best explains the concept of dosage compensation in mammals?

Accepted Answer

It prevents excessive expression of X-linked genes by inactivating one X chromosome in females.

Question 15

A geneticist is studying a trait that shows a 9:3:3:1 ratio in the F2 generation of a cross. What does this ratio indicate about the inheritance of the trait?

Accepted Answer

Two genes are involved, and they assort independently.

Question 16

Which of the following best describes the function of transfer RNA (tRNA) during translation?

Accepted Answer

It brings specific amino acids to the ribosome according to the codon sequence of mRNA.

Question 17

Which of the following is a direct consequence of crossing over during meiosis?

Accepted Answer

Increased genetic variation among gametes

Question 18

Which of the following best describes the purpose of a testcross in classical genetics?

Accepted Answer

To determine the genotype of an individual expressing a dominant phenotype

Question 19

Which of the following is a key feature of epigenetic regulation of gene expression?

Accepted Answer

It involves heritable changes in gene activity without altering the DNA sequence.

Concepts of Genetics: Foundations, Chromosomes, and Mendelian Principles

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