Question 1

Which of the following best describes the difference between a gene and an allele?

Accepted Answer

A gene is a segment of DNA that codes for a functional product, while an allele is a specific version of that gene.

Question 2

Which process during meiosis is primarily responsible for the independent assortment of genes?

Accepted Answer

Metaphase I

Question 3

A plant with genotype $$Rr ($$where $$R is $$dominant for red flowers and $$r is $$recessive for white flowers) is self-pollinated. What is the expected phenotypic ratio in the offspring if the trait shows complete dominance?

Accepted Answer

$$3:1 ($$red:white)

Question 4

Which of the following mechanisms does NOT contribute to genetic variation in sexually reproducing organisms?

Accepted Answer

Binary fission

Question 5

A mutation must occur in which type of cell to be passed on to offspring?

Accepted Answer

Germline cell

Question 6

In a population, a harmful recessive allele becomes more common due to inbreeding. What is the most likely genetic explanation?

Accepted Answer

Inbreeding increases the chance that both parents carry the same recessive allele, leading to homozygosity in offspring.

Question 7

Which of Mendel’s laws explains why a gamete receives only one allele for each gene?

Accepted Answer

Law of segregation

Question 8

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

Accepted Answer

$$50\%$$

Question 9

Which of the following is an example of incomplete dominance?

Accepted Answer

A cross between red and white snapdragons produces pink offspring.

Question 10

Which statement best explains why polyploidy is more common in plants than in animals?

Accepted Answer

Polyploid plants are often viable and fertile, while polyploid animals are usually not viable.

Question 11

A child is born with Down syndrome, which is caused by trisomy 21. Which meiotic error most likely led to this condition?

Accepted Answer

Nondisjunction during meiosis

Question 12

Which of the following best describes codominance?

Accepted Answer

Both alleles are fully expressed in the phenotype of a heterozygote.

Question 13

A hydrangea plant with the same genotype produces blue flowers in acidic soil and pink flowers in alkaline soil. This is an example of:

Accepted Answer

A multifactorial trait

Question 14

If a gamete receives two copies of the same chromosome and another gamete receives none, what is the result after fertilization?

Accepted Answer

Aneuploidy

Question 15

Which of the following is true about linked genes?

Accepted Answer

They are located close together on the same chromosome and tend to be inherited together.

Question 16

Which equation best represents the number of possible chromosome combinations due to independent assortment in human gametes?

Accepted Answer

$$2^{23}$$

Question 17

A female mammal is heterozygous for a gene on the X chromosome. What is the expected result in her somatic cells due to X inactivation?

Accepted Answer

She will be a mosaic for that gene, with some cells expressing one allele and some expressing the other.

Question 18

Which of the following best explains why sexual reproduction contributes to evolution?

Accepted Answer

It increases genetic variation, providing more raw material for natural selection.

Question 19

Which of the following is NOT a possible result of nondisjunction during meiosis?

Accepted Answer

Production of gametes with the normal number of chromosomes

Question 20

Which statement about somatic mutations is correct?

Accepted Answer

They can cause diseases like cancer but are not usually inherited by offspring.

Genetic Variation and Inheritance: Principles and Patterns

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