1. A team of researchers at a pesticide company are working produce a new rodent poison to address a
growing problem of rat infestations at an old waterfront warehouse. The researchers are developing a
poison that will cause the junctions between intestinal cells to break down. The poison will be incorporated
into grain and left where the rodents will feed on it. Which of the following describes the most likely effect
of this poison?
A. The gap junctions will break down resulting in leaks in the digestive tract.
B. The tight junctions will break down resulting in leaks in the digestive tract.
C. The gap junctions will break down and interfere with absorption of nutrients.
D. The tight junctions will break down and interfere with absorption of nutrients.
2. You have identified a novel cytoplasmic protein. Sequence analysis revealed the presence of a number of
serine/threonine phosphorylation target motifs. Based on this data, you hypothesize that this protein may
be a substrate for a
A. protein kinase.
B. receptor tyrosine kinase.
C. G-protein-coupled receptor.
D. phosphotyrosine adapter protein.
3. Why is phosphorylation-dephosphorylation commonly used to regulate signal transduction
pathways?
A. Phosphate groups are efficient second messengers.
B. Protein kinases and phosphatases are endocrine hormones.
C. The hydrolysis of bound GTP results in GDP and Pi.
D. The addition or removal of a phosphate group can change protein activity
4. An example of an effector protein whose activity can be indirectly modulated via a G protein
coupled receptor is
A. a receptor tyrosine kinase.
B. glycogen synthase.
C. adenyl cyclase.
D. Ras.
E. E2F.
5. Which pair are examples of second messengers?
A. Na+, K+
B. serine, threonine
C. estrogen, testosterone
D. glucose, glycogen
E. cAMP, DAG
6. Which of the following statements best fits as an automobile analogy for a gut cell that has
ingested the cholera toxin?
A. The starter is broken.
B. The gas pedal of a car is stuck when pushed down.
C. The brake pedal of a car gets stuck while pushed down.
D. The radio antenna is broken and does not receive signals.
7. Which of the following statements best fits as an analogy for a cell with a mutation in a
tumor-suppressor gene?
A. The starter is broken.
B. The gas pedal of a car does not work at all.
C. The brake pedal of a car gets stuck while pushed down.
D. The brake pedal of a car does not work at all.
8. You have been asked to provide genetic counseling to a family who has a very high incidence
of various types of cancer. After some discussion, you tell them that you will do some genetic
testing to determine if they carry any mutations that predispose them to cancer. Mutations in
which of following proteins are most commonly associated with cancers?
A. E2F and p53
B. Ras and Scr
C. Scr and Rb
D. Rb and p53
9. Which of the following can convert a proto-oncogene to an oncogene?
A. growth factor exposure
B. gene damage
C. pairing of the proto-oncogene with a tumor-suppressor gene
D. cyclin production
10. The progress of the cell cycle is regulated by ______ and their dependent kinases.
A. hormones
B. chromosomes
C. cyclins
D. endocrine signals
11. Which of the following sequence of cell-cycle phases is characteristic of eukaryotes?
A. G to S to M
B. G1 to S to G2 to M to C
C. S to M to C
D. G1 to G2 to S to C
E. G1 to G2 to G3 to S to C
12. In humans the diploid number of chromosomes is 46. The haploid number is 23. Prior to
mitosis in the cell cycle, the cell is in the G2 phase. Which of the statements is true?
A. The homologous chromosomes are lined up on the equator.
B. The homologous chromosomes have all been copied through DNA replication and are now
sister chromatids.
C. The homologous chromosomes have been pulled to their respective poles by the spindle
apparatus.
D. The homologous chromosomes have not been replicated yet.
E. The homologous chromosomes are now in the haploid or n condition.
13. Following S phase, a human cell would have how many pairs of sister chromatids and
individual DNA molecules?
A. 23 pairs of sister chromatids and 46 individual DNA molecules
B. 23 pairs of sister chromatids and 92 individual DNA molecules
C. 46 pairs of sister chromatids and 46 individual DNA molecules
D. 46 pairs of sister chromatids and 92 individual DNA molecules
E. 46 pairs of sister chromatids and 184 individual DNA molecules
The Cell Cycle in an Animal Cell, a play in several acts
The players:
1. Separase; 2. Cohesin; 3. A pair of homologous chromosomes (can exist in condensed
of decondensed states); 4. Kinetochores; 5; Centrioles; Microtubules; 6. Securin; 7.
Nuclear membrane
Act I, in which (ignoring cell cycle checkpoints) key activities take place during the S
phase of the cell cycle
Act II, in which (ignoring cell cycle checkpoints) the cell readies itself for Mitosis
Act III, in which (NOT ignoring the Anaphase [a.k.a Spindle] Checkpoint!) genetic
material is separated to two poles of a dividing cell
Act IV, in which two daughter cells are produced
Assignment: Move tables to sides of room, take 5 minutes to plan the play, dress
rehearsal, perform the play.