BIO 189 Exam 3 Practice Exam

The characteristic indicated by the blackened figures is probably:

Dominant.

How many and what type of daughter cells does meiosis produce?

four haploid

After sperm fertilizes an egg to form a zygote, the zygote can split to form two separate embryos. This would result in...

- Identical twins - Monozygotic twins

Mendel's 1st Law of Segregation means that...

- Two copies of a gene segregate so that each gamete receives only 1 copy of the gene - Has a 3:1 phenotypic ratio

Thirty percent of the bases in a sample of DNA extracted from eukaryotic cells is adenine. What percentage of cytosine is present in this DNA?

20 percent

In a population of 50 turtles, there is an occurrence of an allele for a green color (G). There are 25 G's in this population. What is the allele frequency of G in the population of 50 turtles?

25%

Marfan Syndrome is an autosomal dominant disorder, meaning that there are no carriers of the disease. If a female (Mm) who expresses Marfan Syndrome marries a male (mm) who does not express the disease, what is the percent likelihood of having a child WITHOUT the disorder? (Hint: Draw a punnett square)

50%

What are the genotypes of the parents?

Both are heterozygous

Which component is not directly involved in translation?

DNA

Which enzyme catalyzes the elongation of a DNA strand in the 5' → 3' direction?

DNA polymerase

What is the flow of information for the synthesis of proteins according to the central dogma?

DNA to mRNA to protein

You have developed a mutation that leads to skin cancer and you are pregnant. You are worried that your child will be born with the cancer mutation you have while carrying the baby. Should you be worried?

No, the mutations causing the cancer are in somatic cells, not reproductive germ cells.

DNA replication begins at the ___ in the nucleus. Transcription starts at the ___ and ends at the ___ in the nucleus. Translation starts at the ___ and ends at the ___ in the cytosol.

Origin of replication; promoter, terminator; start codon, stop codon

Which of the following statements is true?

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

How do the daughter cells at the end of mitosis and cytokinesis compare with their parent cell?

The daughter cells have the same number of chromosomes and half the amount of DNA.

Evolution must include a change in...

The gene pool of a population over multiple generations

Chromatids are separated from each other.

The statement is true for mitosis and meiosis II.

Programmed cell death is called

apoptosis

In a population of fish, body coloration varies from a light shade, almost white, to a very dark shade of green. Changes in the environment that result in decreased predation of individuals with the lightest coloration is an example of __________ selection

directional

Vinblastine is a standard chemotherapeutic drug used to treat cancer. Because it interferes with the assembly of microtubules, its effectiveness must be related to

disruption of mitotic spindle formation.

Considering the same population of fish described in the previous question, if the stream environment included several areas of sandy, light-colored bottom areas and a lot of dark-colored vegetation, both the light- and dark-colored fish would have a selective advantage and increased survival in certain places. This type of scenario could explain the occurrence of which type of natural selection?

diversifying/disruptive

A cross between homozygous purple-flowered and homozygous white-flowered pea plants results in offspring with purple flowers. This demonstrates

dominance.

A mutation in which of the following parts of a gene is likely to be most damaging to a cell?

exon

What are the coding segments of a stretch of eukaryotic DNA called?

exons

Calico cats are female because

only females can have Barr bodies.

What is the sequence of a polypeptide based on the following mRNA sequence? The codon table has been provided. 5' . . . UUUUCUUACUGUUUG 3'

phe-ser-tyr-cys-leu

The observable traits expressed by an organism are described as its ________.

phenotype

In the Hardy-Weinberg equation, which term(s) would be used to calculate the genotype frequency of individuals that exhibit a recessive disease?

q^2

The sequence that signals the end of transcription is called the ______________.

terminator

A hurricane kills 98% of a population of cranes. The population eventually rebounds to its original size, but the amount of genetic variation in the rebounded population is significantly less. This is an example of

the bottleneck effect.

Which of the following is a possible gamete for an individual with the genotype yy SS?

yS