Epstein Bar Virus (EBV) causes most of us to have an episode of sore throat and swollen glands during early childhood. If we first become exposed to the virus during our teen years, however, EBV causes the syndrome we know as mononucleosis. However, in special circumstances, the same virus can be carcinogenic.

Epstein Bar Virus (EBV) causes most of us to have an episode of sore throat and swollen glands during early childhood. If we first become exposed to the virus during our teen years, however, EBV causes the syndrome we know as mononucleosis. However, in special circumstances, the same virus can be carcinogenic.

1) In areas of the world in which malaria is endemic, notably in sub-Saharan Africa, EBV can cause Burkitt's lymphoma in children, which is usually associated with large tumors of the jaw. Which of the following is consistent with these findings?

A) EBV infection makes the malarial parasite able to produce lymphoma.
B) Malaria's strain on the immune system makes EBV infection worse.
C) Malaria occurs more frequently in those infected with EBV.
D) Malarial response of the immune system prevents an individual from making EBV antibodies.
E) A cell infected with the malarial parasite is more resistant to the virus.

Answer:  D

2) In a different part of the world, namely in parts of southeast Asia, the same virus is associated with a different kind of cancer of the throat. Which of the following is most probable?

A) Viral infection is correlated with a different immunological reaction.
B) The virus infects the people via different routes.
C) The virus only infects the elderly.
D) The virus mutates more frequently in the Asian population.
E) Malaria is also found in this region.

Answer:  A

3) A very rare human allele of a gene called XLP, or X-linked lymphoproliferative syndrome, causes a small number of people from many different parts of the world to get cancer following even childhood exposure to EBV. Given the previous information, what might be going on?

A) The people must have previously had malaria.
B) Their ancestors must be from sub-Saharan Africa or southeast Asia.
C) They must be unable to mount an immune response to EBV.
D) They must have severe combined immune deficiency (SCID).
E) Their whole immune system must be overreplicating.

Answer:  C

4) What must characterize the XLP population?

A) They must have severe immunological problems starting at birth.
B) They must all be males with affected male relatives.
C) They must all be males with affected female relatives.
D) They must all inherit this syndrome from their fathers.
E) They must live in sub-Saharan Africa.

Answer:  C

A eukaryotic gene has "sticky ends" produced by the restriction endonuclease EcoRI. The gene is added to a mixture containing EcoRI and a bacterial plasmid that carries two genes conferring resistance to ampicillin and tetracycline. The plasmid has one recognition site for EcoRI located in the tetracycline resistance gene. This mixture is incubated for several hours, exposed to DNA ligase, and then added to bacteria growing in nutrient broth. The bacteria are allowed to grow overnight and are streaked on a plate using a technique that produces isolated colonies that are clones of the original. Samples of these colonies are then grown in four different media: nutrient broth plus ampicillin, nutrient broth plus tetracycline, nutrient broth plus ampicillin and tetracycline, and nutrient broth without antibiotics.

A eukaryotic gene has "sticky ends" produced by the restriction endonuclease EcoRI. The gene is added to a mixture containing EcoRI and a bacterial plasmid that carries two genes conferring resistance to ampicillin and tetracycline. The plasmid has one recognition site for EcoRI located in the tetracycline resistance gene. This mixture is incubated for several hours, exposed to DNA ligase, and then added to bacteria growing in nutrient broth. The bacteria are allowed to grow overnight and are streaked on a plate using a technique that produces isolated colonies that are clones of the original. Samples of these colonies are then grown in four different media: nutrient broth plus ampicillin, nutrient broth plus tetracycline, nutrient broth plus ampicillin and tetracycline, and nutrient broth without antibiotics.

1) Bacteria that contain the plasmid, but not the eukaryotic gene, would grow

A) in the nutrient broth plus ampicillin, but not in the broth containing tetracycline.
B) only in the broth containing both antibiotics.
C) in the broth containing tetracycline, but not in the broth containing ampicillin.
D) in all four types of broth.
E) in the nutrient broth without antibiotics only.

Answer:  D

2) Bacteria containing a plasmid into which the eukaryotic gene has integrated would grow in

A) the nutrient broth only.
B) the nutrient broth and the tetracycline broth only.
C) the nutrient broth, the ampicillin broth, and the tetracycline broth.
D) all four types of broth.
E) the ampicillin broth and the nutrient broth.

Answer:  E

3) Bacteria that do not take up any plasmids would grow on which media?

A) the nutrient broth only
B) the nutrient broth and the tetracycline broth
C) the nutrient broth and the ampicillin broth
D) the tetracycline broth and the ampicillin broth
E) all three broths

Answer:  A

A group of six students has taken samples of their own cheek cells, purified the DNA, and used a restriction enzyme known to cut at zero, one, or two sites in a particular gene of interest.

A group of six students has taken samples of their own cheek cells, purified the DNA, and used a restriction enzyme known to cut at zero, one, or two sites in a particular gene of interest.

1) Why might they be conducting such an experiment?

A) to find the location of this gene in the human genome
B) to prepare to isolate the chromosome on which the gene of interest is found
C) to find which of the students has which alleles
D) to collect population data that can be used to assess natural selection
E) to collect population data that can be used to study genetic drift

Answer:  C

2) Their next two steps, in order, should be

A) use of a fluorescent probe for the gene sequence, then electrophoresis.
B) electrophoresis of the fragments followed by autoradiography.
C) electrophoresis of the fragments, followed by the use of a probe.
D) use of a ligase that will anneal the pieces, followed by Southern blotting.
E) use of reverse transcriptase to make cDNA, followed by electrophoresis.

Answer:  C

3) Analysis of the data obtained shows that two students each have two fragments, two students each have three fragments, and two students each have one only. What does this demonstrate?

A) Each pair of students has a different gene for this function.
B) The two students who have two fragments have one restriction site in this region.
C) The two students who have two fragments have two restriction sites within this gene.
D) The students with three fragments are said to have "fragile sites."
E) Each of these students is heterozygous for this gene.

Answer:  B

CML (chronic myelogenous leukemia) results from a translocation between human chromosomes 9 and 22. The resulting chromosome 22 is significantly shorter than usual, and it is known as a Philadelphia (Ph') chromosome. The junction at the site of the translocation causes overexpression of a thymine kinase receptor. A new drug (Gleevec or imatinib) has been found to inhibit the disease if the patient is treated early.

CML (chronic myelogenous leukemia) results from a translocation between human chromosomes 9 and 22. The resulting chromosome 22 is significantly shorter than usual, and it is known as a Philadelphia (Ph') chromosome. The junction at the site of the translocation causes overexpression of a thymine kinase receptor. A new drug (Gleevec or imatinib) has been found to inhibit the disease if the patient is treated early.

1) Which of the following would be a reasonably efficient technique for confirming the diagnosis of CML?

A) searching for the number of telomeric sequences on chromosome 22
B) looking for a Ph' chromosome in a peripheral blood smear
C) enzyme assay for thymine kinase activity
D) FISH study to determine the chromosomal location of all chromosome 22 fragments
E) identification of the disease phenotype in review of the patient's records

Answer:  D

2) Why would Gleevec most probably cause remission of the disease?

A) It reverses the chromosomal translocation.
B) It eliminates the Ph' chromosome.
C) It removes Ph'-containing progenitor cells.
D) The drug inhibits the replication of the affected chromosome.
E) The drug inhibits the specific thymine kinase receptor.

Answer:  E

3) One possible use of transgenic plants is in the production of human proteins, such as vaccines. Which of the following is a possible hindrance that must be overcome?

A) prevention of transmission of plant allergens to the vaccine recipients
B) prevention of vaccine-containing plants being consumed by insects
C) use of plant cells to translate non-plant-derived mRNA
D) inability of the human digestive system to accept plant-derived protein
E) the need to cook all such plants before consuming them

Answer:  A

Pharmacogenetics is an increasingly important discipline that uses genetic information to tailor the prescription of drug treatments to individuals. In the case of chemotherapy for breast cancer, for example, different patients need and/or respond to different treatments.

Pharmacogenetics is an increasingly important discipline that uses genetic information to tailor the prescription of drug treatments to individuals. In the case of chemotherapy for breast cancer, for example, different patients need and/or respond to different treatments.

1) Patients whose tumors are HER-2 positive respond to herceptin whereas other patients do not. Patients whose tumors have estrogen receptors will be best served if

A) their estrogen receptors are blocked by using RNAi.
B) their estrogen release is activated and/or elevated.
C) the estrogen receptors are blocked by other molecules that can use the same receptors.
D) they are given herceptin as well as estrogen.
E) they are given a complete hysterectomy.

Answer:  C

2) Breast tumor biopsy specimens can be typed for a number of gene expression patterns. Together, these can provide risk analysis for the likely aggressive growth and metastasis of the tumor. How can this most help the physician and patient?

A) Some patients want to know as much as possible.
B) This can help them to decide whether and what kind of chemotherapy is warranted.
C) This can help them decide whether the tumor should be removed.
D) Some physicians may use the information to decide what to do, but not tell the patient.
E) This can help to aggregate health statistics.

Answer:  B

Which of the following sequences in double-stranded DNA is most likely to be recognized as a cutting site for a restriction enzyme?

Which of the following sequences in double-stranded DNA is most likely to be recognized as a cutting site for a restriction enzyme?

A) AAGG
TTCC

B) AGTC
TCAG

C) GGCC
CCGG

D) ACCA
TGGT

E) AAAA
TTTT

Answer:  C