Question 1

According to Mendel's law of segregation, what happens to alleles during gamete formation?

Accepted Answer

The two alleles for a gene separate so that each gamete receives only one allele.

Question 2

A plant with genotype $$Pp ($$where $$P is $$dominant for purple flowers and $$p is $$recessive for white flowers) is crossed with a plant with genotype $$pp. $$What is the expected phenotypic ratio of the offspring?

Accepted Answer

1 purple : 1 white

Question 3

Which of the following best describes the concept of a 'testcross'?

Accepted Answer

Breeding an individual of unknown genotype with a homozygous recessive individual to determine the unknown genotype.

Question 4

In a dihybrid cross between two individuals heterozygous for both traits ($$AaBb 	imes AaBb$$), what is the expected phenotypic ratio if the genes assort independently?

Accepted Answer

9:3:3:1

Question 5

Which of the following is an example of codominance?

Accepted Answer

A person with AB blood type expressing both A and B antigens on red blood cells.

Question 6

A genetic disorder is only expressed in individuals who are homozygous for the recessive allele. What is the probability that two carrier parents (both heterozygous) will have an affected child?

Accepted Answer

$$\frac{1}{4}$$

Question 7

Which of the following best explains pleiotropy?

Accepted Answer

A single gene affects multiple phenotypic traits.

Question 8

If a gene exhibits incomplete dominance, what would be the phenotype of the heterozygote in a cross between a red-flowered plant ($$RR) $$and a white-flowered plant ($$rr$$)?

Accepted Answer

Pink

Question 9

Which of the following statements about the law of independent assortment is correct?

Accepted Answer

It applies only to genes located on different, nonhomologous chromosomes or far apart on the same chromosome.

Question 10

A woman with blood type A ($$I^A I^O) $$and a man with blood type B ($$I^B I^O) $$have a child. Which of the following blood types is NOT possible for their child?

Accepted Answer

Type C

Question 11

Which of the following is an example of epistasis?

Accepted Answer

A gene for pigment deposition masks the expression of a gene for pigment color in Labrador retrievers.

Question 12

In polygenic inheritance, which of the following is true?

Accepted Answer

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

Question 13

A man with achondroplasia (a dominant disorder, genotype $$Dd) $$and a woman without the disorder ($$dd) $$have children. What is the probability that their child will have achondroplasia?

Accepted Answer

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

Question 14

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 characteristics.

Question 15

A couple, both carriers for cystic fibrosis (an autosomal recessive disorder), are planning to have two children. What is the probability that both children will be unaffected (either carrier or non-carrier)?

Accepted Answer

$$\frac{9}{16}$$

Question 16

Which of the following scenarios best illustrates Mendel's law of segregation in a real-world context?

Accepted Answer

A child inherits blue eyes from both parents, even though both parents have brown eyes.

Question 17

If a gene has three alleles in a population, how many possible genotypes can exist for that gene?

Accepted Answer

6

Question 18

A woman with genotype $$Pp ($$purple flowers) is crossed with a man with genotype $$Pp. $$What is the probability that their offspring will have white flowers?

Accepted Answer

$$\frac{1}{4}$$

Question 19

Which of the following is NOT a reason why humans are not ideal subjects for genetic research, according to Mendelian principles?

Accepted Answer

Humans have only one allele for each gene.

Question 20

A geneticist is studying a trait controlled by two genes, each with two alleles. If the genes assort independently, how many different types of gametes can an individual with genotype $$AaBb$$ produce?

Accepted Answer

4

Mendel and the Gene Idea: Principles of Inheritance (Chapter 14)

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