Question 1

According to Mendel's model of inheritance, what is the relationship between genes and alleles?

Accepted Answer

Alleles are alternate forms of genes.

Question 2

A pea plant with genotype $Pp$ is crossed with another $Pp$ plant. What is the expected phenotypic ratio of their offspring for flower color, where $P$ is dominant for purple and $p$ is recessive for white?

Accepted Answer

$3$ purple : $1$ white

Question 3

Which of the following best describes the Law of Segregation?

Accepted Answer

Alleles separate during gamete formation so that each gamete carries only one allele for each gene.

Question 4

If a homozygous dominant individual ($TT$) is crossed with a homozygous recessive individual ($tt$) for plant height, what will be the genotype of all offspring?

Accepted Answer

All $Tt$

Question 5

A woman with six fingers on each hand (a dominant trait) and a man with the normal number of digits have a daughter with the normal number of digits. What is the probability that their next child will have extra digits, assuming the woman is heterozygous?

Accepted Answer

$1/2$

Question 6

Which of the following genotypes is heterozygous for a gene with alleles $A$ (dominant) and $a$ (recessive)?

Accepted Answer

$Aa$

Question 7

In a dihybrid cross between two plants heterozygous for both seed color ($Yy$) and seed shape ($Rr$), what is the expected phenotypic ratio among the offspring?

Accepted Answer

$9:3:3:1$

Question 8

A couple are both carriers for a recessive genetic disease (genotype $Dd$). What is the probability that their first three children will all be phenotypically normal?

Accepted Answer

$
\left(\frac{3}{4}\right)^3 = \frac{27}{64}$

Question 9

Which of the following best illustrates the Law of Independent Assortment?

Accepted Answer

The inheritance of flower color does not affect the inheritance of seed shape.

Question 10

If a plant with genotype $YyRr$ (heterozygous for both seed color and shape) self-pollinates, how many different types of gametes can it produce?

Accepted Answer

4

Question 11

A mystery pea plant has tall stems and axial flowers. The allele for tall stems ($T$) is dominant to dwarf ($t$), and the allele for axial flowers ($A$) is dominant to terminal ($a$). Which of the following genotypes is possible for this plant?

Accepted Answer

$TtAa$

Question 12

Which of the following statements about homozygous and heterozygous genotypes is correct?

Accepted Answer

A homozygous genotype has two identical alleles for a gene.

Question 13

In a cross between a heterozygous tall plant ($Tt$) and a homozygous recessive short plant ($tt$), what is the expected ratio of tall to short offspring?

Accepted Answer

$1$ tall : $1$ short

Question 14

Which process during sexual reproduction restores the diploid number of chromosomes in offspring?

Accepted Answer

Fertilization

Question 15

If a true-breeding purple-flowered pea plant ($PP$) is crossed with a white-flowered plant ($pp$), what will be the genotype and phenotype of the F1 generation?

Accepted Answer

All $Pp$, all purple

Question 16

A pea plant heterozygous for three genes ($YyRrIi$) can produce how many different types of gametes?

Accepted Answer

8

Question 17

Which of the following is an example of a phenotype?

Accepted Answer

Purple flowers

Question 18

If two parents are both heterozygous for freckles ($Ff$), what is the probability that their child will NOT have freckles (freckles is dominant)?

Accepted Answer

$
\frac{1}{4}$

Question 19

Which of the following best explains why siblings from the same parents can look different from each other?

Accepted Answer

Meiosis produces gametes with different combinations of alleles due to independent assortment and segregation.

Mendel and the Gene Idea: Principles of Inheritance (Section 14.1)

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