Unit 2 Part 2

Question 1

What does homozygous mean?

Answer 1

An organism is homozygous if it has two identical alleles for a trait.

Question 2

What does heterozygous mean?

Answer 2

An organism is heterozygous if it has two different alleles for a trait.

Question 3

What are alleles?

Answer 3

Alleles are different versions of a gene that determine specific traits.

Question 4

True or False: Dominant alleles can mask the expression of recessive alleles.

Answer 4

True

Question 5

What is a dominant allele?

Answer 5

A dominant allele is one that expresses its trait even in the presence of a recessive allele.

Question 6

What is a recessive allele?

Answer 6

A recessive allele is one that only expresses its trait when two copies are present.

Question 7

Fill in the blank: In a heterozygous genotype, one allele is dominant and the other is __________.

Answer 7

recessive

Question 8

What is the genotype of an organism that has two identical alleles for a trait?

Answer 8

Homozygous

Question 9

What is the genotype of an organism that has one dominant allele and one recessive allele?

Answer 9

Heterozygous

Question 10

True or False: An organism can be homozygous for a dominant allele.

Answer 10

True

Question 11

What is the result of a cross between two homozygous individuals with different traits?

Answer 11

All offspring will be heterozygous.

Question 12

Multiple Choice: Which of the following is an example of a homozygous genotype? A) Aa B) AA C) Ab D) aB

Answer 12

B) AA

Question 13

What is the phenotype of an organism that is heterozygous for a dominant trait?

Answer 13

The phenotype will express the dominant trait.

Question 14

Fill in the blank: If a trait is controlled by multiple alleles, it is known as __________ inheritance.

Answer 14

multiple

Question 15

True or False: All traits are governed by a single pair of alleles.

Answer 15

False

Question 16

What does it mean if a trait exhibits incomplete dominance?

Answer 16

The phenotype of heterozygous individuals is a blend of the two homozygous phenotypes.

Question 17

What is an example of incomplete dominance?

Answer 17

The flower color in snapdragons, where red and white flowers produce pink offspring.

Question 18

Multiple Choice: Which term describes an allele that is not expressed in the presence of a dominant allele? A) Dominant B) Recessive C) Codominant D) Incomplete

Answer 18

B) Recessive

Question 19

Fill in the blank: A __________ allele will always show its effect, even if only one copy is present.

Answer 19

dominant

Question 20

What does it mean for two alleles to be codominant?

Answer 20

Both alleles are fully expressed in the phenotype of the heterozygote.

Question 21

True or False: A recessive trait can be expressed in a heterozygous individual.

Answer 21

False

Question 22

What is the probability of obtaining a homozygous recessive offspring from two heterozygous parents?

Answer 22

25%

Question 23

What is the term for the physical expression of a genotype?

Answer 23

Phenotype

Question 24

Multiple Choice: In a genetic cross, what does the term ‘P generation’ refer to? A) Parental generation B) Phenotypic generation C) Punnett generation D) Progeny generation

Answer 24

A) Parental generation

Question 25

What is the expected phenotype ratio in the offspring of a monohybrid cross between two heterozygous parents?

Answer 25

3:1 ratio of dominant to recessive phenotypes.