Question 1

Which of the following best describes homologous chromosomes?

Accepted Answer

They are chromosomes of the same size and shape, but may carry different alleles for the same genes.

Question 2

How many autosomes are present in a human somatic cell?

Accepted Answer

22 pairs, for a total of 44 autosomes

Question 3

During meiosis, crossing over occurs during which stage?

Accepted Answer

Prophase I

Question 4

A diploid cell ($2n$) in humans contains how many chromosomes?

Accepted Answer

$46$

Question 5

Which statement best explains the law of segregation?

Accepted Answer

Alleles for a trait separate during gamete formation, so each gamete carries only one allele for each gene.

Question 6

If two heterozygous parents for a trait (genotype $Aa$) have a child, what is the probability that the child will be homozygous recessive ($aa$)?

Accepted Answer

$\frac{1}{4}$

Question 7

Which of the following is an example of incomplete dominance?

Accepted Answer

A red-flowered plant crossed with a white-flowered plant produces pink-flowered offspring.

Question 8

In humans, which chromosome combination determines biological male sex?

Accepted Answer

XY

Question 9

A carrier for an X-linked recessive disorder is typically:

Accepted Answer

A female with one normal and one affected X chromosome

Question 10

Which process results in daughter cells that are genetically identical to the parent cell?

Accepted Answer

Mitosis

Question 11

A person with genotype $Tt$ for the ability to taste PTC is crossed with another $Tt$ individual. What is the probability that their child will NOT be able to taste PTC?

Accepted Answer

$\frac{1}{4}$

Question 12

Which of the following best describes a gene?

Accepted Answer

A segment of DNA that codes for a specific protein or trait

Question 13

Which event during meiosis increases genetic variation among offspring?

Accepted Answer

Crossing over between homologous chromosomes

Question 14

If a biological male (XY) inherits an X-linked recessive disorder, which parent must have passed the affected allele?

Accepted Answer

Mother

Question 15

Which of the following is true about codominance?

Accepted Answer

Both alleles are expressed equally in the phenotype.

Question 16

How many homologous pairs are present in a human cell with $2n=46$?

Accepted Answer

$23$

Question 17

Which of the following best describes the difference between sex and gender?

Accepted Answer

Sex refers to biological characteristics, while gender refers to social and cultural roles.

Question 18

Which of the following is NOT a source of genetic variation in sexually reproducing organisms?

Accepted Answer

Replication of DNA during mitosis

Question 19

A true-breeding plant with purple flowers (genotype $PP$) is crossed with a true-breeding plant with white flowers ($pp$). What will be the genotype of the F1 generation?

Accepted Answer

$Pp$

Question 20

Why are there so few Y-linked genetic disorders in humans?

Accepted Answer

The Y chromosome contains very few genes compared to the X chromosome.

Genetics and Chromosomes: Study Guide for General Biology

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