Genetics Pre-test

Factors that control traits are called

• a. genes.

• b. purebreds.

• c.recessives.

• d. parents.

Scientists call an organism that has two different alleles for a trait a

• a. hybrid.

• b. trait.

• c. purebred.

• d. factor.

What does the notation TT mean to geneticists?

• a. two dominant alleles

• b. two recessive alleles

• c. at least one dominant allele

• d. one dominant and one recessive allele

What does the notation Tt mean to geneticists?

• a. two dominant alleles

• b. two recessive alleles

• c. at least one recessive allele

• d. one dominant allele and one recessive allele

What is probability?

• a. the actual results from a series of events

• b. the likelihood that a particular event will occur

• c. the way the results of one event affect the next event

• d. the number of times a coin lands heads up

What does a Punnett square show?

• a. all the possible outcomes of a genetic cross

• b. only the dominant alleles in a genetic cross

• c. only the recessive alleles in a genetic cross

• d. all of Mendel’s discoveries about genetic crosses

If a homozygous black guinea pig (BB) is crossed with a homozygous white guinea pig (bb), what is the probability that an offspring will have black fur?

• a. 25 percent

• b. 50 percent

• c. 75 percent

• d. 100 percent

An organism’s physical appearance is its

• a. genotype.

• b. phenotype.

• c. codominance.

• d. heterozygous.

What is a mutation?

• a. any change that is harmful to an organism

• b. any change in a gene or chromosome

• c. any change that is helpful to an organism

• d. any change in the phenotype of a cell

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

• a. traits

• b. offspring

• c. generations

• d. hybrids