Exam 3 Questions

Question 1

when we say that DNA replication is semiconservative we mean that:
A. only half of an organism’s DNA is replicated during each cell division
B. When DNA is replicated, each new double helix contains one parental strand and one newly synthesized daughter strands
C. When DNA is replicated, one double helix contains both parental strands and one contains newly synthesized daughter strands
D. parental DNA stays in the parent cell and daughter DNA ends up in the daughter cell
E. none of these are correct

Answer 1

B

Question 2

The enzyme that completes the phosphidiester bond along the DNA backbone once RNA primers are removed and replaced with DNA is:
A. DNA polymerase
B. primase
C. DNA replicase
D. DNA ligase
E. none of the above

Answer 2

D

Question 3

which of the following steps in prokaryotic binary fission is incorrect?
A. DNA is replicated in both directions from a single point on the circular chromosome
B. the replicating chromosomes are attached to the cell membrane
C. The cell continues to grow during division, separating the replicating chromosomes
D. the nuclear envelope is reformed prior to cell division
E. none of these statements are incorrect

Answer 3

D

Question 4

the genetic information of daughter cells is the same as the genetic information of the parent in binary fission and meiosis.
A. true
B. false

Answer 4

B

Question 5

The G1/S cyclin- CDK complex:
A. triggers phosphorylation of transcription factors to initiate lipid synthesis
B. phosphorylates proteins that are important for replicating DNA
C. triggers phosphorylation of transcription factors to initiate the process of mitosis
D. both A and C
E. both B and C

Answer 5

A

Question 6

put the following steps of DNA replication is chronological order
1. An RNA primer is created
2. primase binds to the site of oirigin
3. helices breaks hydrogen bonds between base pairs of antiparallel strands
4. DNA polymerase binds to the template strand
5. single stranded binding proteins attach to DNA strands to prevent them from coming back together
A. 2, 1, 3, 4, 5
B. 2,1,3,5,4
C. 3,2,1,4,5
D. 3,4,2,1,5
E. 3,2,1,5,4

Answer 6

C or E

Question 7

Predict what would happen if a tetrad of chromosomes only connected to the mitotic spindle at one of the two kinetochores?
A. the sister chromatids would not separate
B. one of the daughter cells would have an extra copy of that chromosome
C. one of the daughter cells would lack that chromosomes
D. homologous chromosomes would not separate
E. more than one of these is correct

Answer 7

E

Question 8

The sperm cells in the testes of an animal have 16 chromosomes. How many chromosomes are present in the somatic cells of this diploid animal?
A.8
B. 16
C. 32

Answer 8

C

Question 9

Cyclins are examples of:
A. oncogenes
B. secondary messengers
C. tumor suppresors
D. proto oncogenes
E. none of the above

Answer 9

De

Question 10

the amount of \_\_\_ is fairly constant throughout the cell cycle, but the amount of \_\_\_ varies.
A. Cyclins; cyclin dependent kinase
B. DNA; cyclins
C. cyclin dependent kinase; DNA
D. DNA; cyclin dependent kinase
E. both D and B

Answer 10

C

Question 11

predict what would happen if a mutation caused the replication checkpoint to be bypassed during the cell cycle.
A. the cell would enter S phase even though there is damaged DNA in the nucleus.
B. the cell will enter mitosis but will fail to complete cytokinesis
C. the cell might enter mitosis before replication is complete
D. the cell will never enter mitosis, it will stall at G2
E. all of these are outcomes

Answer 11

C

Question 12

Paramecium is a single cell eukaryotic organism that can reproduce by mitotic cell division. During interphase, but before M phase of the cell cycle, which of the following must occur?
A. the cell must faithfully and fully replicate its chromosomes
B. the cell must increase in size
C. damaged DNA must be repaired
D. the cell must produce machinery responsible for DNA synthesis
E. all of these events must occur

Answer 12

E

Question 13

of the following, the most likely to contribute to uncontrolled cell proliferation is:
A. a mutant kinetochore protein that causes reduced microtubule attachment
B. a mutant microtubule synthesis/polymerization enzyme
C. a mutant S cyclin that is non functional
D. a mutant CDK that binds irreversibly to an inhibitor, shutting off kinase activity
E. a mutant p53 that cannot be phosphorylated

Answer 13

E

Question 14

Homologous chromosomes can be defined as:
A. identical double helices of DNA that are the products of DNA replication
B. chromosome pairs that cannot form chiasma
C. chromosomes pairs that share the same genes but differ in gene order
D. chromosome pairs one inherited from the paternal parent the other from the maternal parent
E. pairs of chromosomes between different species that carry approximately the same genes in the same locations

Answer 14

D

Question 15

What is the advantage of the proofreading function of DNA polymerase?
A. allows the polymerase to detect the insertion of an incorrect base during replication
B. DNA polymerase is always present and can repair all mutations when they occur
C. DNA polymerase can be recruited to recently mutated sites to repair mutations
D. all DNA mutations can be detected and repaired during DNA replication
E. bothA and D

Answer 15

A

Question 16

Which of the following would not be a consequence of the inability of the cell to produce microtubules during cell division or meiosis?
A. the sister chromatids would not separates.
B. the mitotic spindle would not form
C. homologous chromosomes would not separate
D. Plant cells could not construct the cell plate
E. cytokinesis in animals could not occur

Answer 16

E

Question 17

In general what causes normal cells to become cancer cells?
A. loss of cell cycle control
B. loss of the ability to divide
C. cell cycle stop
D. metastasis
E. DNA polymerase overactivity

Answer 17

A

Question 18

Tumor suppressors are genes involved in the control of the cell cycle. Which of the following statements describe tumor suppressor genes?
1. Genes that code for proteins that normally promote cell division
2. mutations that increase activity of these genes may lead to cancer
3. mutations that decrease activity of these genes may lead to cancer
4. some products of these genes normally function in repairing damaged DNA
5. these genes code for proteins that normally inhibit cell division
A. 1,3,4
B. 1,4
C. 2,5
D. 3,4,5
E. 3,4

Answer 18

D

Question 19

Delta and Notch signaling molecules that function through 
A. autocrine signaling
B. paracrine signaling
C. contact dependent signaling
D. endocrine signaling
E. none of the above

Answer 19

C

Question 20

Which type of signal receptor can transmit signals by activating RAS?
A. nuclear receptor
B. GPCR
C. receptor kinase 
D. ligand dated ion channel
E. none of these

Answer 20

C

Question 21

Consider a mutant form of the EGF receptor kinase called Her2/neu. The mutant form of the receptor kinase is linked to cancer because the receptor molecule is locked in the on or activated position. Which of the following mechanisms could cause this to occur?
A. the mutant receptor lacks the ability to phosphorylate
B. the mutant receptor dimerizes in the absence of the ligand
C. rather than add phosphate groups the mutant receptor removes phosphates
D. the mutant receptor lacks the ability to dimerize
E. the mutant receptor cannot form cyclic AMP

Answer 21

B

Question 22

phosphates are a family of enzymes that remove phosphate groups from proteins, deactivating them. Triuvec is a drug that inhibits phosphates in eukaryotic cells. What effect would Triuvec have on the response of cells to signals received by receptor kinases?
A. the ligand would still bind the receptor so there would be no effect
B. the ligand would bind the receptor but the signal wouldn’t be transmitted to the nucleus
C. target proteins would remain in an activated state, promoting transcription
D. cAMP could not be converted to AMP resulting in activated protein kinase A
E. the response of the cell cannot the predicted

Answer 22

C

Question 23

A G-protein with GDP bound to it\_\_\_\_.
A. is in its active state
B. signals a protein to maintain its shape and conformation
C. directly affects gene expression
D. will use cGMP as a second messenger
E. is in an inactive state

Answer 23

E

Question 24

Colchicine is a drug that disrupts the normal assembly and disassembly of microtubules. based on this information, which of the following would not be affected by colchicine?
A. dynamic instability
B. vesicle trafficking powered by kinesin
C. vesicle trafficking powered by dynein
D. vesicle trafficking powered by myosin
E. migration of chromosomes to opposite poles of a dividing cell

Answer 24

D

Question 25

During photosynthesis, \_\_\_ is reduced to\_\_\_\_.
A. water; carbon dioxide
B. carbon dioxide; oxygen
C. oxygen ; water
D. glucose ; oxygen
E. carbon dioxide ; glucose

Answer 25

E

Question 26

The interior of the chloroplast is referred to as the:
A. cytoplasm
B. grana
C. stroma
D. lumen
E. inter membrane space

Answer 26

C

Question 27

Which of the following molecules are oxidized during photosynthesis?
A. ADP and a triose phosphate
B. ADP and 3-PGA
C. NADPH and 3-PGA
D. NAD+ and a triose phosphate
E. NADPH and H2O

Answer 27

E

Question 28

Suppose a plant is exposed to a toxin that causes the thylakoid membranes to become much more permeable to protons than normal. Which of the answer choices would be true?
A. the reduction step of the Calvin cycle would slow down and eventually stop
B. the reduction and regeneration steps of the Calvin cycle would slow and eventually stop
C. the regeneration step of the Calvin cycle would slow down and eventually stop
D. the carboxylation and reduction step s of the Calvin cycle would slow and eventually stop
E. none of these

Answer 28

B

Question 29

Xanthophylls reduce \_\_\_ by accepting energy from \_\_\_ and releasing it as \_\_\_. 
A. photorespiration; chlorophyll; CO2
B. ROS; chlorophyll; heat
C. ROS ; the ETC; fluorescence
D. CO2; photosynthesis ; heat
E. none of the above

Answer 29

B

Question 30

Which of the statements is true regarding ROS?
A. ROS are formed when excess electrons are added to O2
B. ROS are likely to form if NADP+ is low in supply
C. ROS can form when O2 is exposed to excess light energy
D. ROS can be neutralized by antioxidants
E. all of these

Answer 30

E

Question 31

How does an activated receptor protein transfer information from outside the cell to inside the cell?
A. through a conformational change of the receptor
B. by altering the ligand binding site of the receptor
C. by decreased phosphorylation of the receptor
D. by increased translation of the receptor
E. both A and B

Answer 31

A

Question 32

What causes the inactivation of a G protein?
A. the alpha submit catalyzes the hydrolysis of GTP to GDP and inorganic phosphate
B. the Beta and gamma subunits trigger the hydrolysis of GTP to GDP
C. a phosphatase removed the inorganic phosphate group from GTP
D. the inactive receptor catalyzes the replacement of GTP by GDP

Answer 32

A

Question 33

At which stage of the cell cycle could you see sister chromatids with a microscope?
A. G2
B. S
C. M
D. G1
E. they are visible at all stages

Answer 33

C

Question 34

the microtubules that form the mitotic spindle extend out front the centrosome. Where would you expect to find the plus end of a spindle microtubule?
A. away from the centrosome and away from the kinetochore
B. toward the centrosome and away from the kinetochore
C. away from the centrosome and toward the kinetochore
D. toward the centrosome and toward the kinetochore
E. none of these

Answer 34

C