Question 1

Which of the following best describes Mendel's 'particulate' hypothesis of heredity?

Accepted Answer

Parents pass on discrete heritable units—genes—that retain their separate identities in offspring.

Question 2

In Mendel's experiment with pea plants, what was the observed ratio of purple to white flowers in the F2 generation?

Accepted Answer

$$3:1$$

Question 3

Which law states that the segregation of alleles for one gene occurs independently of that for any other gene?

Accepted Answer

Law of Independent Assortment

Question 4

A pea plant with genotype $$Tt ($$where $$T is $$tall and $$t is $$dwarf) is self-pollinated. What is the probability that an offspring will be dwarf?

Accepted Answer

$$1/4$$

Question 5

Which of the following is an example of incomplete dominance?

Accepted Answer

A heterozygote has a phenotype intermediate between both homozygotes, such as pink snapdragon flowers from red and white parents.

Question 6

In a dihybrid cross between $$YyRr$$ and $$YyRr$$ pea plants, what is the expected phenotypic ratio in the F2 generation?

Accepted Answer

$$9:3:3:1$$

Question 7

Which term describes an individual with two identical alleles for a gene?

Accepted Answer

Homozygous

Question 8

A gene that masks the expression of another non-allelic gene is called:

Accepted Answer

Epistatic gene

Question 9

Which of the following best illustrates pleiotropy?

Accepted Answer

A gene that influences multiple phenotypes, such as PKU causing both mental impairment and light hair color.

Question 10

If a disease is caused by a recessive allele, what is the genotype of a carrier?

Accepted Answer

Heterozygous

Question 11

Which of the following is true about codominance?

Accepted Answer

Both alleles are fully expressed in the heterozygote, such as MN blood type.

Question 12

What is the probability of obtaining a heterozygote ($$Aa) $$from a cross between two heterozygotes ($$Aa 	imes Aa$$)?

Accepted Answer

$$1/2$$

Question 13

Which of the following is an example of polygenic inheritance?

Accepted Answer

Skin color in humans

Question 14

Which genetic test is non-invasive and analyzes cell-free fetal DNA in maternal blood to screen for chromosomal disorders?

Accepted Answer

Non-invasive prenatal testing (NIPT)

Question 15

A summer squash plant with genotype $$CcGg is $$selfed. What is the expected ratio of white:yellow:green fruit in the F2 generation?

Accepted Answer

$$12:3:1$$

Question 16

Which of the following statements about Mendel's laws is correct?

Accepted Answer

The law of dominance states that the dominant allele determines the organism's appearance when two alleles differ.

Question 17

Which of the following is NOT a reason Mendel chose garden peas for his experiments?

Accepted Answer

They have complex genetic traits that are difficult to analyze.

Question 18

Which of the following best describes the norm of reaction?

Accepted Answer

The range of phenotypes produced by a genotype under different environmental conditions.

Question 19

A couple, both carriers for a rare recessive genetic disease, have a child. What is the probability that their child will be affected by the disease?

Accepted Answer

$$1/4$$

Question 20

Which of the following is a dominant genetic disorder that typically manifests symptoms in adulthood?

Accepted Answer

Huntington's disease

Basics of Genetics: Mendel and the Gene Idea

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