Question 1

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 2

In Mendel's pea plant experiments, what was the expected phenotypic ratio of purple to white flowers in the F2 generation?

Accepted Answer

$$3:1$$

Question 3

Which of the following best explains the Law of Segregation?

Accepted Answer

Alleles for a trait separate into different gametes during meiosis.

Question 4

A woman who is heterozygous for a recessive X-linked trait (such as color blindness) has children with a man who does not carry the trait. What is the probability that their son will express the trait?

Accepted Answer

$$0.5$$

Question 5

Which of the following is an example of incomplete dominance?

Accepted Answer

A cross between red and white flowers produces pink flowers.

Question 6

Which chromosomal abnormality is associated with Down syndrome?

Accepted Answer

Trisomy 21

Question 7

If two heterozygous individuals for cystic fibrosis (a recessive genetic disorder) have a child, what is the probability that the child will have cystic fibrosis?

Accepted Answer

$$0.25$$

Question 8

Which of the following best describes pleiotropy?

Accepted Answer

One gene affects multiple traits.

Question 9

A dihybrid cross is performed between two heterozygous pea plants ($$RrYy 	imes RrYy). $$What is the expected phenotypic ratio in the offspring?

Accepted Answer

$$9:3:3:1$$

Question 10

Which of the following is an example of codominance?

Accepted Answer

A person with AB blood type expresses both A and B antigens.

Question 11

Which genetic phenomenon explains why calico cats have patches of different colors?

Accepted Answer

X-inactivation

Question 12

Which of the following best describes the effect of a multifactorial trait?

Accepted Answer

It is influenced by both genetic and environmental factors.

Question 13

Which of the following chromosomal changes is NOT a structural abnormality?

Accepted Answer

Trisomy

Question 14

A man with genotype $$AaBb$$ produces gametes. According to Mendel's Law of Independent Assortment, which gamete combinations are possible?

Accepted Answer

$$AB, Ab, aB, ab$$

Question 15

Which of the following diseases is caused by a single gene mutation and leads to progressive neurological decline?

Accepted Answer

Huntington's disease

Question 16

Which of the following best describes epistasis?

Accepted Answer

One gene masks or modifies the expression of another gene.

Question 17

A karyotype is used to:

Accepted Answer

Assess the number and structure of chromosomes.

Question 18

Which of the following is NOT a genetically transmitted disease?

Accepted Answer

Influenza

Question 19

If a child inherits one allele for sickle-cell anemia from each parent, what is the child's genotype and phenotype?

Accepted Answer

Genotype: $$ss$$, Phenotype: sickle-cell anemia

Question 20

Which of the following best explains why males are more likely to express X-linked recessive traits?

Accepted Answer

Males have only one X chromosome, so a single recessive allele will be expressed.

Genetics and Chromosome Structure: Study Notes for General Biology

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