CELL CYCLE & Signal Transmitters

Question 1

How many discrete phases are there in the cell cycle

1. 1
2. 3
3. 2
4. 4
5. 5

Answer 1

4.

cell cycle phases are:

1. G1.Growth
2. S. DNA-Synthesis
3. G2. Growth and preparation for Mitosis
4. M. Mitosis

Question 2

what is not true about DNA Synthesized

1. only during one phase of the cell cycle
2. continuously during the cell cycle
3. only during a small portion of the interphase
4. in the S phase

Answer 2

2

Question 3

During The G1 Phase, The Cell Is:

1. metabolically inactive but continuously growing
2. metabolically active and grows
3. metabolically inactive and is replicating DNA
4. not replicating DNA

Answer 3

2

Question 4

Typical Duration For The Discrete Cell Cycles Phase G1,S,G2 And M Phase Are Respectively

1. 11 - 8 - 4 - 1 hours
2. 4 - 11 - 8 - 1 hours
3. 1 - 8 - 11 - 4 hours
4. 8 - 11 - 4 - 1 hours

Answer 4

1

G1,S, G2, M

11+8+4+1= 24 hrs.

Question 5

If appropriate growth factors are not available in the G1 phase

1. the cell enters in a quiescent G0 phase
2. the cell cycle stops at the restriction point
3. the cell enters apoptosis

Answer 5

1,2

Question 6

Cell cycle Control in animal oocytes is taking place

1. in the G1 phase
2. in the G2 phase
3. in the M phase after endogenous hormonal stimulation

Answer 6

2

Question 7

Vertebrate Oocytes can remain arrested a long time in

1. M phase
2. G1 phase
3. G2 phase
4. none of the above

Answer 7

3.

note that: 1st meiosis phases(prophase1-metaphase1-anaphase1-telophase1) all involved in G2 cell cycle.

while meiosis2 (mitosis) involved in M cell cycle

Question 8

The Checkpoints in the cell cycle for?

Answer 8

• check for damaged DNA at the end of the G1 phase
• check for un-replicated or damaged DNA at the end of G2 phase
• check for chromosome misalignment at the end of the M phase

Question 9

Which Checkpoint is mediated by the action of P53

1. G2 checkpoint
2. G1 checkpoint
3. Checkpoint Charley
4. M checkpoint

Answer 9

2

Question 10

MPF Maturation Promoting Factor

1. is only present in oocytes
2. is also present in somatic cells
3. is a general regulator of the transition from G2 to M phase

Answer 10

2 and 3

remember G2= 1st meiosis phases

Question 11

Progress from G1 to S phase passes by a regulatory checkpoint in the cell cycle called:

1. STOP
2. START
3. CONTINU

Answer 11

2

Question 12

MPF is Composed of

1. Cdc2 and cyclin B
2. Cdc2 and cyclin A
3. Cdc2 and cyclin C

Answer 12

1

Question 13

The 2 critical regulation position on MPF are

1. threonine 161 and tyrosine 15 on Cyclin A
2. thyroxine 161 and tyrosine 15 on Cdc2
3. threonine 161 and tyrosine 15 on Cyclin B
4. threonine 161 and tyrosine 15 on Cdc2

Answer 13

4

Question 14

Which isn’t involved cyclin in the progression from the G1 to the S phase from the cell cycle

1. Cyclin D1
2. Cyclin E
3. Cyclin D2
4. Cyclin D3
5. Cyclin C

Answer 14

5

cyclins involved in the progression from G1 to S phase are

(Cyclin D1,D2,D3 and Cyclin E)

Question 15

Mitosis is induced by:

1. Phosphorylation of MPF
2. De-Phosphorylation of MPF

Answer 15

2

Question 16

Cyclins D synthesis is induced by:

1. Growth factors
2. hormones

Answer 16

1

Question 17

Cyclic AMP (cAMP)

1. inhibits proliferation into the G1 phase by acting on p27
2. promotes proliferation into the G1 phase

Answer 17

1

(note: increase cAMP involved in the arrest phase)

Question 18

What is the Transforming Growth Factor Beta TGF-b-ß (inhibin, activin, AMH, BMP)??

Answer 18

Transforming Growth Factor Beta TGF-b-ß

1. is an extracellular inhibitor of animal cell proliferation
2. involved in synthesis of p15 and p27 which block the cyclin CDK
3. suppresses the expression of the gene c-mos

Question 19

Which do NOT belong to the TGF-Beta Superfamily (transforming growth factor β)?

1. Anti Müllerian Hormone
2. Inhibins
3. Activin
4. Decapentaplegic
5. Cryptin

Answer 19

5

Question 20

Steroid Hormonal Regulation is an example of which type of Cell Signaling?

1. Paracrin
2. Autocrine
3. Endocrine

Answer 20

3

Question 21

The action of Neurotransmitters is an example of which type of cell signaling ?

1. Paracrine
2. Autocrine
3. Endocrine

Answer 21

1

Question 22

In vertebrates the response to foreign antigens is an example of which type of cell signaling?

Answer 22

Autocrine

Question 23

Which is Correct?

1. Steroid hormones are hydrophobic
2. Steroid hormones can diffuse across the plasma membrane
3. Steroid hormones bind to intracellular receptors
4. Steroid hormones regulate directly gene expression

Answer 23

all correct

steroid hormones:

hydrophobic⇒ diffuse across the plasma membrane⇒ bind to intracellular receptors

⇒ Regulate gene expression

Question 24

Which is Correct , Steroid Receptors?

1. are polysacharides
2. contain related domains for ligand binding
3. contain related domains for DNA binding
4. are transcription factors

Answer 24

2, 3, and 4

Steroid Receptors: ►are transcription factors

• contain related domains for ligand binding
• contain related domains for DNA binding

Question 25

Which one of the following substances is NOT a Neurotransmitter?

1. Acetylcholine
2. Glycine
3. Glutamate
4. Dopamine
5. Norepinephrine
6. Epinephrine
7. Serotonin
8. Heparin
9. Histamine
10. Gamma -Aminobutyric acid

Answer 25

8.

Heparin is not a Neurotransmitter

while⇔

Acetylcholine, Glycine, Glutamate, Dopamine, Norepinephrine, Epinephrine, Serotonin, Histamine and Gamma -Aminobutyric acid are Neurotransmitter substances

Question 26

Which is correct?

1. Neurotransmitter are hydrophilic
2. Neurotransmitters are able to cross the plasma membrane of their target cells
3. Many neurotransmitters are ligand-gated ion channels

Answer 26

1 and 3

Question 27

The widest variety of Signaling Molecules in animals are peptides.

1. Yes
2. No

Answer 27

1

Question 28

Neurotransmitters are Hydrophilic Molecules that Bind to Surface Receptors

1. Yes
2. No

Answer 28

1

Question 29

Eicosanoids are Lipid Signaling Molecules.

1. Yes
2. No

Answer 29

1

Question 30

Which is NOT a Eicosanoid ( lipid signaling molecule)?

1. Prostaglandine
2. Prostacyclin
3. Tromboxanes
4. Cytokines

Answer 30

4