Ch.12

Question 1

M phase

Answer 1

The most dramatic of the cell cycle, involving a major reorganization of all cell components.

Question 2

What happens during mitosis?

Answer 2

• The chromosome condense
• The nuclear envelope of most cells break down
• The cytoskeleton reorganizes to form mitosis spindle, and the chromosome move to the opposite poles.

Question 3

Closed mitosis

Answer 3

Some cells do not have nuclear envelope breakdown during mitosis, like yeast.

Question 4

Prophase

Answer 4

• Beginning phase of mitosis

- marked by appearance of condense chromosome and the development of mitotic spindle.

Question 5

Metaphase

Answer 5

Chromosomes are aligned on a metaphase plate in the center of the cell.

Question 6

Anaphase

Answer 6

Sister chromatid separate and move to opposite poles of the spindle.

Question 7

Telophase

Answer 7

Final phase of mitosis, during which the nuclei re-form and chromosome decondense.

Question 8

Prometaphase

Answer 8

Transition period between prophase and metaphase during which the microtubules of the mitotic spindle attach to the kinetochore of condensed chromosome.

Question 9

What does MPF do?

Answer 9

It causes 1)chromatin condensation by phosphorylation of condensins. 2)nuclear envelope break down by phosphorylation of lamins, nuclear pore complexes, and inner nuclear membrane protein.3) fragmentation of Golgi apparatus by phosphorylation of golgi matrix proteins.4) spindle formation by phosphorylation of centrosome and microtubule associated proteins.

Question 10

How do nuclear envelope break down?

Answer 10

• nuclear pore complexes dissociate
• nuclear lamina depolymerize by MPF phosphorylation.
• nuclear membrane fragments. (nuclear membrane is absorbed into ER, ER remain intact an distributed to daughter cells.)

Question 11

The break down of the nuclear envelope allows…

Answer 11

Some of the spindle microtubules to attach to chromosome at their kinetochores.

Question 12

What are cell cycle check points?

Answer 12

M-chromosome misalignment
G1-damaged DNA
S-unreplicated or damaged DNA
G2-unreplicated or damaged DNA

Question 13

Spindle assembly checkpoint

Answer 13

Monitors the alignment of chromosome on the metaphase spindle.

Question 14

Anaphase promoting complex(APC)

Answer 14

Ubiquitin ligase that triggers progression from metaphase to anaphase by signaling the degradation of cyclin B and cohesin.

Question 15

E1

Answer 15

Ubiquitin activating enzyme

Question 16

E2

Answer 16

Ubiquitin conjugating enzyme

Question 17

E3

Answer 17

Ubiquitin protein ligase

Question 18

Activation of the APC results in what?

Answer 18

In ubiquination and activation of 2 key target proteins(cohesin and condensin)

Question 19

Where do kinetochore attach?

Answer 19

Microtubule

Question 20

Seperase

Answer 20

Cut cohesin

Checked by protein called securin

Question 21

Condensins

Answer 21

Members of a class of structural maintanance of chromatin or smc proteins that play key roles in organization of eukaryotic chromosomes.

Question 22

Cohesin

Answer 22

Family of smc proteins that contribute to chromosome segregation(structural maintanance of chromatin) during mitosis.

Question 23

Key for spindle assembly check point

Answer 23

Cohesin and cyclin B are important for APC

Question 24

How do microtubules grow or shrink?

Answer 24

By adding or dissociating of subunits

Question 25

Cytokinesis in higher plants

Answer 25

Have hard cell wall and form plate in the middle(plasmadesmata)

Question 26

Mitotic entry

Answer 26

Break down of nuclear envelope, formation of bipolar spindle, attachment of microtubules to kinetochore.

Question 27

Mitotic exit

Answer 27

Spindle assembly check point controls the anaphase promoting complex(APC) to degrade cyclin B and cohesin

Question 28

Meiosis

Answer 28

Specialized kind of cell cycle that reduce the chromosome number by half, resulting in the production of haploid daughter cells.

Question 29

Process of meiosis

Answer 29

• leptotene
• zygotene
• pachytene
• diplotene
• diakinesis

Question 30

Leptotene

Answer 30

Initial stage of extended prophase of meiosis1 during which homologous chromosomes pair before condensation.

Question 31

Zygotene

Answer 31

Homologous chromosomes become closely associated

Question 32

Pachytene

Answer 32

Recombination takes place between homologous chromosome

Question 33

Diplotene

Answer 33

Homologous chromosome separate along their length but remain associated at chiasmata

Question 34

Diakinesis

Answer 34

Final stage of prophase of meioeis1 during which chromosome fully condense and cell progresses to metaphase.

Question 35

Chiasmata

Answer 35

Sites of recombination that link homologous chromosomes during meiosis.

Question 36

Where is the first regulatory point in oocyte meiosis?

Answer 36

In the diplotene stage of the first mieotic division.

Question 37

Polar body

Answer 37

Small cell formed by asymmetric cell division following meiosis of oocyte.

Question 38

Meiosis of oocytes are controlled by what?

Answer 38

By the activity of cdk1/cyclin B complexes

Question 39

Cytostatic factor(CSF)

Answer 39

Cytoplasmic factor that acts to arrest oocyte meiosis at metaphase II.

Question 40

Emi2

Answer 40

Protein level goes up inhibiting APC and degradation of cyclinB. MPF is activated and can’t go to interphase (transcription).

Question 41

Fertilization

Answer 41

• Process in which the sperm binds to receptor on the surface of the egg and fuses with the egg plasma membrane, initiating the development of a new diploid organism containing genetic information derived from both parents.
• the increase in cytosolic ca2+ following fertilization signals the completion of meiosis.(zygote is a fertilized egg)

Question 42

Where does ca comes from?

Answer 42

ER

Question 43

What causes degradation of Emi2?

Answer 43

CaMK II and PIK1.
APC will be activated
Cyclin B will be degraded
MPF will be turn off and goes to interphase.