Genetics

Question 1

Role of histone methyltransferase

Answer 1

Increasing the activity of histone methyltransferase would increase the proportion of histones that were methylated and this is a form of epigenetic regulation. This in turn would decrease gene expression of the gene of interest

Question 2

Which amino acid would least likely be contained in histones?
K: Lysine
N: Asparagine
E: Glutamic Acid
H: Histidine

Answer 2

C. Glutamic acid-Negatively charged and the least likely to be contained in high proportions in the histone because the negative charge of glutamate would repel the negative charge of DNA, preventing association

Question 3

Heterochromatin

Answer 3

The portion of chromatin that is found in a tightly wound state that represses transcription of genes.
-Increased chromosome condensation would correlated with heterochromatin

Question 4

Euchromatin

Answer 4

The portion of DNA that is not tightly bound to histones and is open for transcription

Question 5

Chromosomal looping serves to increase transcription by:

Answer 5

Increasing the frequency of RNA polymerase II association with the transcription start site.

Question 6

Scientists interested in identifying the specific locus of a gene would most likely use:

Answer 6

Fluorescence in situ hybridization (FISH)

Question 7

CpG dinucleotides in the genome are often methylated compared to C in another nucleotide context. Methylated CpG sites would be expected around:
I. Centromeres
II. Transcriptionally active genes
III. Heterochromatin

Answer 7

C. I and III only

-Methylated CpG are around heterochromatin (repressed gene expression)

Question 8

The nucleolus is the site of synthesis for what component of translation?

Answer 8

B. Ribosome

Question 9

Stop codons in eukaryotes

Answer 9

UGA
UAA
UAG

Question 10

Histone acetylases represent what type of genetic modification?

Answer 10

Epigenetic

Question 11

Which of the following statements regarding fetal circulation is FALSE?

a. In the umbilical cord, there are more arteries than veins.
b. The foramen ovale is the only shunt that connects two chambers of the heart.
c. Blood flow in the ductus arteriosus is from the aorta to the pulmonary artery
d. The ductus venosus is the only shunt that bypasses the liver

Answer 11

c. Blood flow in the ductus arteriosus is from the aorta to the pulmonary artery

Question 12

Where is an RNA transcript that is undergoing alternative splicing most likely to be located in cancer cells?

Answer 12

D. Nucleus

Question 13

An antibody used to isolate the 40S subunit of an actively translating ribosome is likely to pull down:
I. mRNA
II. tRNA
III. rRNA

Answer 13

I, II, and III

Question 14

Serine-arginine rich proteins are likely:
A. Basic, negatively charged
B. Acidic, positively charged
C. Polar
D. Aromatic

Answer 14

C. Polar

Question 15

Overexpression of telomerase is most likely to result in:

Answer 15

Cellular immortality

Question 16

Nucleoside analogues would be LEAST likely to induce apoptosis in:
I. hematopoietic stem cells
II. neurons
III. skeletal muscle

Answer 16

I. hematopoietic stem cells
II. neurons
III. skeletal muscle

Question 17

Which of the following is the most likely reason that cancer cells show overexpression of genes involved in homologous recombination?

Answer 17

B. Stalling of the replication fork during S phase requires rescue by homologous recombination.

Question 18

S phase of the cell cycle is LEAST likely to regulate:

Answer 18

D. Actin polymerization from the centrosome