Question 1

Which of the following best describes the relationship between DNA, genes, and chromosomes?

Accepted Answer

Chromosomes are made of genes, which are made of DNA.

Question 2

A scientist is analyzing a karyotype and observes three copies of chromosome 21. What condition does this indicate, and what is the underlying cause?

Accepted Answer

Down syndrome; caused by nondisjunction resulting in trisomy 21.

Question 3

During which phase of mitosis do sister chromatids separate and move toward opposite poles of the cell?

Accepted Answer

Anaphase

Question 4

Which of the following processes increases genetic diversity during sexual reproduction?

Accepted Answer

Crossing over during prophase I of meiosis

Question 5

A plant cell is observed forming a structure between two new nuclei at the end of mitosis. What is this structure, and how does it differ from animal cell division?

Accepted Answer

Cell plate; animal cells form a cleavage furrow instead.

Question 6

Given the DNA sequence $$5'	ext{-}ATGCGTACG-3'$$, what is the complementary mRNA sequence produced during transcription?

Accepted Answer

$$5'	ext{-}UACGCAUGC-3'$$

Question 7

Which of the following best explains why not all genes are expressed in all cells at all times?

Accepted Answer

Gene regulation ensures that only necessary genes are transcribed and translated in a given cell type.

Question 8

A woman with genotype $$I^A I^O ($$blood type A) and a man with genotype $$I^B I^O ($$blood type B) have a child. What are the possible blood types of their offspring?

Accepted Answer

A, B, AB, or O

Question 9

Which of the following statements about the flow of genetic information is correct?

Accepted Answer

Transcription converts DNA into mRNA, which is then translated into protein.

Question 10

A cell with 46 chromosomes undergoes mitosis. How many chromosomes will each daughter cell have, and how does this compare genetically to the parent cell?

Accepted Answer

46 chromosomes; genetically identical to the parent cell

Question 11

Which of the following best describes the function of restriction enzymes in genetic engineering?

Accepted Answer

They cut DNA at specific sequences, allowing insertion of new genes.

Question 12

A man with genotype $$X^A Y$$ and a woman with genotype $$X^A X^a$$ have a son. What is the probability that their son will express the recessive sex-linked trait?

Accepted Answer

25%

Question 13

Which of the following is a direct result of nondisjunction during meiosis?

Accepted Answer

Production of gametes with abnormal numbers of chromosomes

Question 14

Which of the following best describes the role of plasmids in producing human insulin using bacteria?

Accepted Answer

Plasmids are used as vectors to carry the human insulin gene into bacterial cells.

Question 15

Which of the following is a benefit of genetically modified (GM) crops such as Bt corn?

Accepted Answer

They are resistant to certain pests, reducing the need for chemical pesticides.

Question 16

Which of the following best explains why most syndromes caused by nondisjunction involve sex chromosomes rather than autosomes?

Accepted Answer

Abnormal numbers of autosomes are usually lethal, while sex chromosome abnormalities are more often survivable.

Question 17

Which of the following statements about PCR (polymerase chain reaction) is correct?

Accepted Answer

PCR amplifies specific DNA sequences, not the entire genome.

Question 18

In gel electrophoresis, how does the length of DNA fragments affect their migration through the gel?

Accepted Answer

Shorter fragments move farther than longer fragments.

Question 19

Which of the following best describes incomplete dominance?

Accepted Answer

The heterozygote displays a phenotype intermediate between the two homozygotes.

Question 20

Which of the following is the correct complementary base pairing in DNA?

Accepted Answer

Adenine pairs with thymine; guanine pairs with cytosine.

Cell Division, Genetics, and Molecular Biology: Study Guide

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