Exam 4

Question 1

Which strand will be the template for leading strand synthesis?

Answer 1

Right (3’ to 5’)

Question 2

What does DNA polymerase 3 add the next nucleotide to?

Answer 2

The 3’ OH

Question 3

Which of the following would allow a cancer cell to divide in the absence of growth factors?

Answer 3

Mutant, active Raf and an absence of Rb

Question 4

Which kinase phosphorylates Mek?

Answer 4

Raf

Question 5

Which phosphorylates Rb?

Answer 5

Cyclin D-cdk

Question 6

Interphase consists of?

Answer 6

G1, G2, S

Question 7

Which of following best describes how insulin signals cells?

Answer 7

Insulin binds to a receptor which then initiates signal transduction which then leads to the cell taking up glucose

Question 8

In growth factor signaling, which molecule enters the nucleus to phosphorylates a transcription factor and initiate expression of the cyclin D gene?

Answer 8

Erk-P

Question 9

Which portion of the receptor tyrosine kinase binds the signal molecule?

Answer 9

A. The very top hook looking part

Question 10

If leptin is made but can’t bind its receptor, what do you predict about weight and leptin levels?

Answer 10

High weight; high leptin

Question 11

A child’s leptin receptors cannot bind leptin. What do you predict about the child’s weight?

Answer 11

Overweight/ obese

Question 12

A mouse that cannot make leptin will be?

Answer 12

Overweight

Question 13

Where is leptin made?

Answer 13

Adipose tissue (fat)

Question 14

What signal is sent by leptin?

Answer 14

A feeling of satiety (fullness)

Question 15

A child produces leptin but is still obese. Which of the following could explain this finding?

Answer 15

He has no leptin receptors and his leptin cannot bind his leptin receptor

Question 16

A child’s receptors cannot bind leptin. Will treatment with leptin help his weight?

Answer 16

No it will not help

Question 17

In terms of a signaling pathway, at what step does leptin act?

Answer 17

Reception

Question 18

Which portion of the receptor tyrosine kinase shown below becomes phosphorylated?

Answer 18

C) the little thingy with the things sticking out

Question 19

After receiving a signal from a neuron, a muscle contracts. What stage of cell signaling does the contraction represent?

Answer 19

Response

Question 20

Which portion of the receptor tyrosine kinase shown below has kinase activity?

Answer 20

C) the part with the little things sticking out

Question 21

What do kinases do?

Answer 21

Phosphorylate a target

Question 22

A chromosome has two complete sister chromatids. What phase of the cell cycle could it be in?

Answer 22

G2

Question 23

When is cdk active?

Answer 23

Late G1

Question 24

If a normal, healthy liver were to be biopsies and stained for Erk-P and cyclin D, what would be observed in terms of amount of stain for each?

Answer 24

Low Erk-P; low cyclin D

Question 25

Which enzyme separates the two strands of DNA in preparation for replication?

Answer 25

Helicase

Question 26

Which protein is the "gate keeper" of cell cycle progression?

Answer 26

Rb

Question 27

A cell is not being stimulated by growth factors. However Raf (B-Raf) is active and the cell is dividing. What could explain this?

Answer 27

A mutation that makes B-Raf permanently active, a mutant receptor with permanently phosphorylated tails, a mutated Ras that is locked into the GTP-bound state

Question 28

Which of the following would cause a mouse to be underweight?

Answer 28

An overproduction of leptin

Question 29

Which of the following best describes a centrosome?

Answer 29

A microtubule organizing center at each spindle pole

Question 30

A cell contains condensed chromosomes and a fragmented nuclear envelope. Some chromosomes have one chromatid attached to the spindle, and some have none. What stage of mitosis is this cell in?

Answer 30

Prometaphase

Question 31

Which of the following processes contributes to the movement of chromosomes during mitosis?

Answer 31

Microtubule shortening and microtubule motors

Question 32

During which stage of mitosis do kinetochore/ spindle microtubule shorten?

Answer 32

Anaphase

Question 33

A DNA molecule is 30% C. What is the % of T?

Answer 33

20

Question 34

A DNA molecule is 30% C. What is the % G?

Answer 34

30

Question 35

During which stage of mitosis do daughter chromosomes separate?

Answer 35

Anaphase

Question 36

Based on the diagram which chromosomes would be detected as a problem by the spindle checkpoint in mitosis?

Answer 36

B,C,D because there isn't a straight line across all the others

Question 37

Where do spindle microtubules attach to chromosomes?

Answer 37

At kinetochores

Question 38

Which of the following is associated with both leading and lagging strand synthesis?

Answer 38

DNA polymerase 3

Question 39

Which of the following is associated only with lagging strand synthesis?

Answer 39

More than one RNA primer

Question 40

Which strand associates itself with lagging strand synthesis?

Answer 40

3' to 5'

Question 41

A person is experiencing excessive bleeding and bruising. Which cell type is likely to be defective and/or deficient in this person?

Answer 41

Platelets

Question 42

What does Gleevec do?

Answer 42

Inhibits BCR-ABL

Question 43

Which proteins are responsible for the constriction of the cleavage furrow during animal cell cytokinesis?

Answer 43

Actin and myosin

Question 44

A chromosome in the nucleus contains?

Answer 44

DNA and proteins

Question 45

In CML, what is activating the growth factor signaling pathway?

Answer 45

BCR-ABL

Question 46

A cell has arrested (stalled/stopped) very early in S phase. Which drug could cause this to happen?

Answer 46

A drug that prevents synthesis of "A" nucleotides (nucleotides with an adenine base)

Question 47

Which cell type transports O2 in blood?

Answer 47

Red blood cells

Question 48

In the presence of BCR-ABL and the absence of growth factors, what do you predict about Ras?

Answer 48

It will be bound to GTP

Question 49

Where are blood cells made?

Answer 49

Bone marrow