PDBIO FINAL part 2

Assume that a G1 somatic cell nucleus in a Myrmecia female contains 16 picograms of DNA. How much DNA would be expected in a meiotic metaphase I cell of a female

32 picograms

Glucose-6-phosphate is inherited as an X-linked recessive gene in humans. A woman whose father suffered from it marries a normal man. What proportion of their sons will have it? If the husband was different would you change your answer?

1/2, no

Suppose two AaBbCc individuals are mated. Assuming that the genes are not linked, what fraction of the offspring are expected to be homozygous for the three recessive traits

1/64

A man and a woman are both of normal pigmentation, but both have one parent who is albino. Albinism is autosomal recessive trait. What is the probability their first child will be an albino girl?

1/8

Given that females of M. pilosula have 16 picograms of DNA in a G1 cell, how much DNA would be expected in a meiotic metaphase I cell of a male

16 picograms

Interestingly, ants were originally described as single species, but actually they are closely related. Assume that a cross occurs between a species with 32 chromosomes and a species with 9 chromosomes. How many chromosomes cells would be expected in the hybrid female?

25

In rabbits, the homozygous CC is normal, Cc results in deformed legs, and cc results in very short legs. The genotype BB produces black fur, Bb brown fur, and bb white fur. If a cross is made between brown rabbits with deformed legs and white rabbits with deformed legs, what percentage of the offspring would be expected to have deformed legs and white fur?

25%

The horse, has 32 pairs of chromosomes; the donkey has 31 pairs. How many chromosomes would be expected in the tissue of a mule

63

How many unique gametes could be produced through independent assortment by an individual with the genotype AaBbCCDdEE?

8

Which of the following figures would most likely represent a correct configuration of the complete chromosomal compliment in a meiotic metaphase I cell of a female ant?

A

The somatic cells of a particular male organism conatin only one pair of homologous chromosomes, call these chromosomes A1A2, and one additional chromosome without a homolog, call it chromosome Q. What chromosomal combination would be likely in the four meiotic products of a single cell?

A1Q, A1Q, A2, A2

Scientists isolate cells at various stages of the cell cycle. They find a group of cells that have 1 1/2 times more DNA than the parent cell has during its normal growth and functioning stage. This cell is in

S phase

When scientists fused two cells in different stages of the cell cycle (e.g. interphase and prophase), they found that the interphase nucleus entered the M phase of the cell cyle. How did they interpret the results.

Some chemical signaling molecule must be present that promotes entry of the cell into M phase

Once researchers understood that chromosomes are moved by the spindle microtubules, the next question they wanted to answer is how the microtubules function to bring about this process.They used flourescent labels to make the chromosomes and the microtubular structures flouresce. When andaphase began (centromeres split), they photobleached a section of microtubules. As chromosomes moved towards the poles of the daughter cells, the photobleached sections of the microtubules remained stationary. This suggests that

The microtubles elongate and shorten at the kinetochore end.

Assume that a particular human cell is examined under a microscope, and it contains 22 autosomes and a Y chromosome. The cell is most likely to be

a sperm cell

A black guinea pig crossed with an albino guinea pig produced 12 black offspring. When the albino was crossed with a second black animal, 6 blacks and 6 albinos were obtained. What is the best explanation for this genetic situation?

albino is recessive, black is dominant

The M-phase checkpoint is designed to make sure all chromosomes are attached to the mitotic spindle. In what stage of mitosis would these cells be most likely to arrest?

metaphase

If a pair of homologous chromosomes fails to seperate during anaphase of meiosis I in a particular cell, what will be the chromosome number of the four resulting gametes of that cell?

n+1; n+1; n-1; n-1

A brain cell tumor is likely a glioma. This means it arises from the support cells of the brain (astrocytes, ependymal cells) rather than from the nerve cells themselves. Why is a brain tumor unlikely to arise from nerve cells

nerve cells have lost their ability to divide and thus are unlikely to begin dividing out of control

Crossing over usually contributes to genetic variation by exchanging chromosomal segments between

non-sister chromatids of homologous chromosomes

Based on the preceding information, at the molecular level, one would expect the mutant form Rb to be

recessive

Pseudohypertropic muscular dystrophy is a human disorder that causes deterioration of the muscles. Only boys are effected, and they are born to normal parents. Due to the severity of the disease, the boys die in their teens. Is this disorder likely dominant or recessive? Is it sex-linked or autosomal?

recessive, sex-linked

Skeletal muscle cells can have several nuclei per cell. How might this happen?

repeated mitosis without the final step of cytokinesis

A heterozygous, but phenotypically wild-type fruit fly was mated to a gray fruit fly. The offspring had this distribution. What is the conclusion from these results?

the black and vestigal loci are linked

A parent cell divides to for two genetically identical daughter cells in the process of mitosis. For mitosis to take place:

the parent cell must replicate its entire genome prior to mitosis