Two chromosomes that have the same genes but may have different
alleles of those genes are said to be __________.
A. Homologous.
B. Sister chromatids.
C. Identical.
D. Duplicated.
After DNA replication, a cell with damaged DNA or too many
mutations does not enter mitosis because of __________.
A. Crossover.
B. The G2/M checkpoint.
C. Trisomy.
D. Cytokinesis.
Which of the following is not an event of the
mitotic phase?
A. Formation of two new nuclei
B. Chromosome segregation
C. Mitotic spindle formation
D. DNA replication
Which of the following is a feature of cancer cells but not of
normal cells?
A. Growth factor dependence
B. Contact inhibition
C. Anchorage independence
D. Normal chromosome number
Which of the following statements regarding Down syndrome
is false?
A. The chance of Down syndrome decreases with the age of the
mother.
B. Trisomy 21 is the cause of Down syndrome.
C. People with Down syndrome usually have a shorter life span
than normal.
D. Down syndrome is the most common serious birth defect in the
United States.
Homologous chromosomes
A. have different alleles of different genes.
B. have the same alleles of the same genes.
C. have different alleles of the same genes.
D. have the same alleles of different genes.
Phenylketonuria (PKU) and oculocutaneous albinism (OCA or just
albinism) are both recessive, monogenic diseases caused by
A. A genetic deficiency in hormone signaling.
B. Bacterial infection.
C. Genetic overproduction of a toxic protein.
D. A genetic loss of enzyme activity.
Most genetic disorders are recessive, for example cystic
fibrosis. A person born with cystic fibrosis likely had parents who
were
A. Slightly affected by the disease, showing some but not all of
the symptoms.
B. Subjected to some environmental toxin that caused the disease
in their children.
C. Not affected at all by the disease.
D. Both affected by the disease.
In cats short hair is dominant to long hair. You find a cat of
unknown origin with short hair and to determine its genotype, you
cross it to a cat with long hair. Of eight kittens born, four have
short hair and four have long hair. What do you conclude about the
genotype of your unknown cat.
A. It's homozygous for the dominant allele.
B. You can't draw any conclusion from the information given.
C. It's homozygous for the recessive allele.
D. It's heterozygous.
Red-green colorblindness is an X-linked recessive disorder. A
woman with red-green colorblindness has children with a man with
normal vision. What is the probability of their having a colorblind
son?
A. 75%
B. 50%
C. 25%
D. 100%