Question 1

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

Accepted Answer

Genotype is an individual's complete set of alleles, while phenotype is the observable trait resulting from genotype and environmental factors.

Question 2

A child inherits one allele for a trait from each parent. If the alleles are represented as 'A' (dominant) and 'a' (recessive), which genotype will result in the expression of the recessive phenotype?

Accepted Answer

$$aa$$

Question 3

Which statement about dominant and recessive alleles is correct?

Accepted Answer

Dominant alleles are expressed if present, even in the heterozygous state.

Question 4

Which of the following is an example of codominance in humans?

Accepted Answer

Blood type AB, where both A and B antigens are expressed on red blood cells.

Question 5

If a mother is heterozygous for freckles ($$Ff) $$and the father is homozygous recessive ($$ff$$), what is the probability that their child will have freckles?

Accepted Answer

$$50\%$$

Question 6

Which genetic disorder is caused by a lethal dominant allele, but persists in the population because symptoms appear in midlife?

Accepted Answer

Huntington disease

Question 7

A couple, both heterozygous for a recessive genetic disorder ($$Dd$$), have a child. What is the probability that the child will inherit the disorder?

Accepted Answer

$$25\%$$

Question 8

Which of the following best explains the origin of new alleles in a population?

Accepted Answer

Alleles are created by random mutations and errors not corrected before cell division.

Question 9

In a Punnett square analysis, if both parents are heterozygous for a trait ($$Aa$$), what is the expected ratio of genotypes among their offspring?

Accepted Answer

$$1\ AA : 2\ Aa : 1\ aa$$

Question 10

Which of the following scenarios demonstrates incomplete dominance?

Accepted Answer

A cross between a red-flowered plant and a white-flowered plant produces pink-flowered offspring.

Question 11

Which chromosomal abnormality is associated with Down syndrome?

Accepted Answer

Trisomy 21

Question 12

Which of the following best describes Mendel's principle of segregation?

Accepted Answer

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

Question 13

A karyotype is used in genetic testing to:

Accepted Answer

Detect abnormalities in chromosome number and structure.

Question 14

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

Accepted Answer

Normal chromosome number in all gametes

Question 15

Which of the following best explains why Huntington disease persists in the human population?

Accepted Answer

Affected individuals often reproduce before symptoms appear.

Question 16

Which of the following is an example of a polygenic trait?

Accepted Answer

Height

Question 17

If a child has Tay-Sachs disease, which of the following must be true about the parents?

Accepted Answer

Both parents are carriers (heterozygous) for the recessive allele.

Question 18

Which of the following best describes the role of environmental factors in determining phenotype?

Accepted Answer

Environmental factors can influence the expression of inherited alleles, affecting phenotype.

Question 19

A genetic counselor is most likely to recommend genetic testing for which scenario?

Accepted Answer

A person whose sibling has a known genetic disorder.

Genetics and Inheritance: Principles, Terminology, and Applications

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