Question 1

Which of the following best explains why Mendel's experiments with pea plants were so successful in uncovering the basic principles of heredity?

Accepted Answer

He chose traits with clear, contrasting phenotypes and used controlled crosses with large sample sizes.

Question 2

Which of the following statements about the process of meiosis is correct?

Accepted Answer

Cells become haploid after Anaphase I, when homologous chromosomes are separated.

Question 3

A scientist is studying a disease caused by a mutation in a gene located on the X chromosome. If a heterozygous female (X^A X^a) is crossed with a normal male (X^A Y), what is the probability that a son will inherit the disease allele?

Accepted Answer

$$\frac{1}{2}$$

Question 4

Which of the following best describes the difference between prokaryotic and eukaryotic chromosomes?

Accepted Answer

Prokaryotic chromosomes are circular and lack histones, while eukaryotic chromosomes are linear and associated with histones.

Question 5

Which of the following is a key feature of the Germ-plasm theory, as proposed by Weismann?

Accepted Answer

Only germ cells contribute genetic information to the next generation.

Question 6

During which stage of Prophase I in meiosis does crossing over occur, and what is the structure that facilitates this process?

Accepted Answer

Pachytene; synaptonemal complex

Question 7

A dihybrid cross between two individuals heterozygous for both genes (AaBb x AaBb) produces offspring with which phenotypic ratio?

Accepted Answer

$$9:3:3:1$$

Question 8

Which of the following best explains the role of the SRY gene in mammals?

Accepted Answer

It triggers the development of male characteristics by initiating testis formation.

Question 9

A researcher observes a tortoiseshell cat with patches of orange and black fur. Which genetic mechanism best explains this phenotype?

Accepted Answer

Random inactivation of one X chromosome in each cell, as described by the Lyon hypothesis.

Question 10

Which of the following equations would you use to calculate the probability of obtaining exactly $$k$$ successes in $$n$$ independent trials, each with probability $$p of $$success?

Accepted Answer

$$P = n! / [k!(n-k)!] \cdot p^k \cdot (1-p$$)^{n-k}$$

Question 11

Which of the following best describes the function of cohesin and shugoshin during meiosis?

Accepted Answer

Cohesin holds sister chromatids together, and shugoshin protects cohesin at the centromere during meiosis I.

Question 12

A plant breeder wants to determine the genotype of a pea plant with a dominant phenotype. Which type of cross should they perform?

Accepted Answer

Testcross with a homozygous recessive individual

Question 13

Which of the following statements about viruses is correct?

Accepted Answer

Viruses lack cellular structure and cannot reproduce independently.

Question 14

Which of the following is a key difference between mitosis and meiosis?

Accepted Answer

Mitosis involves one cell division, while meiosis involves two consecutive cell divisions.

Question 15

Which of the following best describes the principle of independent assortment?

Accepted Answer

Alleles for different genes assort independently of one another during gamete formation.

Question 16

A geneticist uses the chi-square test to compare observed and expected progeny ratios. Which equation should they use to calculate the chi-square statistic?

Accepted Answer

$$\$$chi^2$$ = \sum \frac{(O - E)^2$}{E}$$

Question 17

Which of the following is a real-world example of selective breeding that has had a significant social and economic impact?

Accepted Answer

The development of modern corn (maize) from teosinte through artificial selection.

Question 18

Which of the following best explains why meiosis leads to genetic variation in gametes?

Accepted Answer

Each gamete receives a random combination of maternal and paternal chromosomes due to independent assortment and crossing over.

Question 19

Which of the following statements about dosage compensation in mammals is correct?

Accepted Answer

Dosage compensation is achieved by inactivating one X chromosome in females, forming a Barr body.

Question 20

Which of the following best describes the function of the Xist gene in X chromosome inactivation?

Accepted Answer

It produces an RNA molecule that coats the X chromosome, leading to its inactivation.

Genetics Study Guide: Key Concepts from Chapters 1–4

Study Guide - Practice Questions

Study Guide - Flashcards