Genetics: the Science of Heredity

What did Gregor Mendel do to study different characteristics in his genetics experiments?

• He studied only asexual plants.

• He studied only tall and short pea plants.

• He cross-pollinated plants.

• He cross-pollinated both plants and animals.

What does the notation TT mean to geneticists?

• two dominant alleles

• heterozygous alleles

• at least one dominant allele

• one dominant and one recessive allele

What is the probability of producing a tall pea plant from a genetic cross between two hybrid tall pea plants?

• one in four

• two in four

• three in four

• four in four

What does a Punnett square show?

• all the possible outcomes of a genetic cross

• only the dominant alleles in a genetic cross

• only the recessive alleles in a genetic cross

• all of Mendel’s discoveries about genetic crosses

A purebred chicken with white feathers is crossed with a purebred chicken that has black feathers. Each of their offspring has both black and white feathers. Why does this happen?

• Both alleles for feather color are dominant.

• Both alleles for feather color are recessive.

• The alleles for feather color are neither dominant nor recessive.

• Several alleles work together to determine the trait.

What is the chromosome theory of inheritance?

• Chromosomes are carried from parents to offspring on hybrids.

• Genes are carried from parents to offspring on chromosomes.

• Hybrid pairs of chromosomes combine to form offspring.

• Codominant genes combine to form new hybrids.

What happens during meiosis?

• Two sex cells combine.

• Chromosome pairs separate and are distributed into new sex cells.

• Each sex cell copies itself to form four new chromosomes.

• Chromosome pairs remain together when new sex cells are formed.

Which term refers to physical characteristics that are studied in genetics?

• traits

• offspring

• generations

• hybrids

An organism’s genotype is its

• genetic makeup.

• feather color.

• physical appearance.

• stem height.

Which of the following traits is influenced by both inheritance and environmental factors?

• the ability to sing well

• the ability to cough

• natural hair color

• dyed hair color