BIO 120 Exam 4

Which of the following sentences state a significant
conclusion that Gregor Mendel drew from
his experiments with pea plants?

Traits are inherited in discrete units and are not the result of "blending.

Why did all of the F1 offspring of Mendel's purple
and white flowered pea cross always look like one of the two
parental varieties?

One allele was dominant.

Which of the following statements correctly describes how
Mendel explained why traits disappeared in the F1 generation and then
reappeared in the F2 generation?

Traits can be dominant or recessive, and the recessive traits were
"hidden" by the dominant ones in the F1.

Albinism is a recessive trait where an individual does not
produce the pigment melanin. A man and woman both produce
melanin, but both have one parent with albinism. What is the
probability that their first child will have albinism?

1/4

In pea plants, the tall phenotype is dominant to the dwarf
phenotype. If a heterozygous pea plant is crossed with a homozygous
tall pea plant, what is the probability that the offspring will be dwarf in
size?

0

Which of the following inheritance patterns describes the
ability of a single allele to have multiple phenotypic effects?

pleiotropy

In some parts of Africa, the frequency of individuals who
are heterozygous for the sickle-cell anemia allele is higher than the
frequency in North America, presumably because this reduces the
frequency of malaria. Such a relationship is related to which of the
following?

C) Darwin's theory of natural selection

Males are more often affected by X-linked traits than are
females because ________

D) males only carry one copy of the genes on the X chromosomes

Which of the following statements regarding gene linkage
is correct?

The closer two genes are on a chromosome, the lower the
probability that a crossover will occur between them

Cinnabar eye color is an X-linked, recessive
characteristic in fruit flies. If a female having cinnabar eyes is crossed
with a male having wild-type, red eyes, what percent of the F1 males
will have cinnabar eyes?

100%

A recombination frequency of 50% indicates ________.

The two genes will likely experience recombination

Which of the following statements explains the
observation that closely linked genes are typically inherited together?

the genes are located close together on the same chromosome.

A sample of double-stranded DNA contains 42%
cytosine. Approximately what percent of the nucleotides in this sample
will be thymine?

8%

Rosalind Franklin's X-ray crystallography data suggested
DNA is double stranded and has a uniform diameter. These
observations can be used to rule out base pairing between two of the
same nucleotide because ________

an A-A pair is wider than a C-C
pair

Which list the provides the correct enzymes required for
replicative budding?

helicase, primase, topoisomerase

After DNA replication, the resulting daughter DNA
double helix contains one strand of the original parental DNA and one
new strand. What is the explanation for this phenomenon?

A) DNA replication is semiconservative.