Genetics review for 6-13

In a pair of alleles, the one that masks the other and determines the phenotype is called:

• Recessive

• Dominant

• Inactive

• Passive

Which of the following is a characteristic of asexual reproduction?

• Increased genetic diversity

• Formation of gametes

• Involvement of two parents

• Offspring genetically identical to the parent

Why is genetic variation important in sexual reproduction?

• It ensures that all offspring are clones of their parents.

• It decreases the adaptability of organisms to changing environments.

• It increases the chances that some individuals can thrive if the environment changes.

• It simplifies the genetic makeup of populations.

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

• Genotype is the observable trait, while phenotype is the genetic code.

• Genotype is the genetic code, while phenotype is the observable trait.

• Both genotype and phenotype refer to the genetic code.

• Both genotype and phenotype refer to the observable traits.

In a cross between two heterozygous parents for a dominant trait (Tt x Tt), what is the probability of offspring being homozygous recessive?

• 0%

• 25%

• 50%

• 75%

Which term best describes an organism that carries two identical alleles for a particular gene?

• Heterozygous

• Homozygous

• Dominant

• Recessive

Mutations can be:

• Always harmful to the organism.

• Always beneficial to the organism.

• Harmful, beneficial, or neutral, depending on the environment.

• Without any effect on the organism's fitness.

A plant with the genotype Tt is crossed with a plant with the genotype tt. What proportion of the offspring will have the dominant phenotype?

• 100%

• 75%

• 50%

• 25%

In humans, the allele for widow's peak (W) is dominant to the allele for straight hairline (w). If a homozygous dominant individual has children with a heterozygous individual, what is the probability of each child having a widow's peak?

• 0%

• 50%

• 75%

• 100%

How much genetic information does each sex cell contribute in sexual reproduction?

• Half

• The full amount

• A quarter

• A third