Question 1

Which of the following best describes the main difference between mitosis and meiosis in eukaryotic cells?

Accepted Answer

Mitosis results in two genetically identical diploid cells, while meiosis results in four genetically unique haploid cells.

Question 2

A human somatic cell contains 46 chromosomes. After meiosis, how many chromosomes will each resulting gamete contain?

Accepted Answer

$$23$$

Question 3

Which process during meiosis increases genetic variation by exchanging segments between homologous chromosomes?

Accepted Answer

Crossing over

Question 4

A karyotype is most useful for which of the following purposes?

Accepted Answer

Identifying chromosomal abnormalities such as trisomy 21

Question 5

Which of the following best describes the structure of a prokaryotic chromosome?

Accepted Answer

A single circular DNA molecule without histones

Question 6

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

Accepted Answer

S phase

Question 7

Which of the following is a key difference between mitosis in plant and animal cells?

Accepted Answer

Plant cells form a cell plate during cytokinesis, while animal cells form a cleavage furrow.

Question 8

Cancer is most directly linked to which of the following cellular processes?

Accepted Answer

Uncontrolled mitosis due to failure of cell cycle regulation

Question 9

Gregor Mendel’s experiments with pea plants were significant because they demonstrated which of the following?

Accepted Answer

Inheritance follows specific patterns governed by discrete units called genes.

Question 10

In a dihybrid cross between two heterozygous individuals ($$RrYy 	imes RrYy$$), what is the expected phenotypic ratio of the offspring, assuming independent assortment?

Accepted Answer

$$9:3:3:1$$

Question 11

Which of the following best defines the term 'epistasis'?

Accepted Answer

One gene masks or modifies the expression of another gene.

Question 12

A woman who is a carrier for hemophilia (an X-linked recessive disorder) has children with a man who does not have hemophilia. What is the probability that their son will have hemophilia?

Accepted Answer

$$0.5$$

Question 13

Which of the following scenarios is an example of nondisjunction?

Accepted Answer

Homologous chromosomes fail to separate during meiosis I, resulting in gametes with $$n+1 or$$ $$n-1$$ chromosomes.

Question 14

Which of the following best describes polygenic inheritance?

Accepted Answer

Multiple genes contribute to a single trait, resulting in continuous variation.

Question 15

If a test cross between a plant with an unknown genotype and a homozygous recessive plant produces only dominant phenotype offspring, what is the genotype of the unknown plant?

Accepted Answer

Homozygous dominant

Question 16

Which of the following is true about codominance?

Accepted Answer

Both alleles are fully expressed in the heterozygote.

Question 17

A pedigree shows a trait that appears in every generation and affects both males and females equally. What is the most likely mode of inheritance?

Accepted Answer

Autosomal dominant

Question 18

Which of the following best describes the difference between genotype and phenotype?

Accepted Answer

Genotype refers to the genetic makeup, while phenotype refers to the observable traits.

Question 19

Which of the following is an example of polyploidy?

Accepted Answer

A plant species with four sets of chromosomes ($$4n)$$

Question 20

Which of the following best explains Mendel’s law of segregation?

Accepted Answer

Each individual has two alleles for each gene, which separate during gamete formation so that each gamete receives only one allele.

BIO 121 Unit 4 Study Guidance: Genetics, Cell Division, and Chromosomes

Study Guide - Practice Questions

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