The Cell Cycle

Front 1

Regulator of cell cycle in eukaryotic cells

Back 1

Protein Kinases
-Which are controlled by growth factors

Front 2

Events during Mitosis

Back 2

1 hour
Seperation of daughter cells
Cell division (cytokinesis)

Front 3

Events during Interphase

Back 3

G1, S, G2
Chromosomes decondense
Nucleus appears uniform

Front 4

G0

Back 4

Phase in which cell continues to do normal physiological function but does not divide

Front 5

Early Embyonic Cells

Back 5

Cell cycle lasts 30 min or less
NO cell growth
NO G1 and G2 phases
DNA replication is very rapid

Front 6

Regulation of Cell Cycle

Back 6

External signals-->growth factors
Internal signals-->cell growth, DNA replication, mitosis

Front 7

G1

Back 7

START point is present
Once initiated, there is no turning back

Front 8

G2

Back 8

Stimulated by extracellular signals like hormones.

Front 9

G1 Phase Checkpoint

Back 9

DNA is repaired before entering the S phase

Front 10

S Phase Checkpoint

Back 10

DNA damage is repaired before it is replicated
DNA misincorporation is repaired before it is replicated

Front 11

G2 Checkpoint

Back 11

Prevents mitosis if DNA replication is not complete or DNA is damaged

Front 12

M Phase Checkpoint

Back 12

Prevents mitosis if the daughter chromosomes are not aligned.

Front 13

Mechanism of cell cycle arrest

Back 13

-Sensor protein detect DNA damage
-Senor proteins activate ATM and ATP
-Phosphorylation of Chk 1 & 2 & ATM increase levels of p53 which leads to cell cycle arrest

Front 14

Role of MPF

Back 14

Maturation Promoting Factor
Required to transition from G2 to M phase

Front 15

Cyclin B

Back 15

A regulatory subunit required for Cdc2 protein kinase activity

Front 16

P-Thr-161

Back 16

Required for Cdc2 kinase activity

Front 17

P-Try-15 & P-Thr-14

Back 17

Inhibit Cdc2 kinase activity

Front 18

Activation of MPF is dependent on?

Back 18

Dephosphorylation of Try-15 and Thr-14

Front 19

Triggers the degradation of Cyclin B

Back 19

Activation of Cdc2

Front 20

Activates transcription of p21

Back 20

Increase in level of p53

Front 21

Mechanism of p21

Back 21

1) Inhibits Cdk/cyclin complexes by binding to them leading to cell cycle arrest
2) Bind to PCNA to inhibit DNA replication

Front 22

Events in Mitosis

Back 22

1) Chromosome condensation
2) Formation of mitotic spindle
3) Attachment of chromosomes to spindle
4) Seperation of sister chromatids
5) Formation of daugher nuclei

Front 23

4 Stages in Mitosis

Back 23

Prophase
Metaphase
Anaphase
Telophase

Front 24

Prophase

Back 24

Beginning-Appearance of condensed chromosomes
End-Breakage of nuclear envelope in higher eukaryotes

Front 25

Metaphase

Back 25

Chromosomes align in the center of mitotic spindle

Front 26

Anaphase

Back 26

Breakage of the link between the sister chromatids

Front 27

Telophase

Back 27

Nuclei reform and chromosomes decondense, cell begins to break apart

Front 28

Processes which are promoted by activated MPF

Back 28

Chromatin condensation
Nuclear envelope breakdown
Fragmentation of Golgi and ER
Spindle Formation

Front 29

Cytokinesis

Back 29

Completion step of mitosis
Intiated in late anaphase
Triggered by inactivation of MPF
Contraction of actin-myosin filaments

Front 30

Result of mitosis

Back 30

Diploid daughter cells
Identical genetic components

Front 31

Mechanism of p21

Back 31

1) Inhibits Cdk/cyclin complexes by binding to them leading to cell cycle arrest
2) Bind to PCNA to inhibit DNA replication

Front 32

Events in Mitosis

Back 32

1) Chromosome condensation
2) Formation of mitotic spindle
3) Attachment of chromosomes to spindle
4) Seperation of sister chromatids
5) Formation of daugher nuclei

Front 33

4 Stages in Mitosis

Back 33

Prophase
Metaphase
Anaphase
Telophase

Front 34

Prophase

Back 34

Beginning-Appearance of condensed chromosomes
End-Breakage of nuclear envelope in higher eukaryotes

Front 35

Metaphase

Back 35

Chromosomes align in the center of mitotic spindle

Front 36

Anaphase

Back 36

Breakage of the link between the sister chromatids

Front 37

Telophase

Back 37

Nuclei reform and chromosomes decondense, cell begins to break apart

Front 38

Processes which are promoted by activated MPF

Back 38

Chromatin condensation
Nuclear envelope breakdown
Fragmentation of Golgi and ER
Spindle Formation

Front 39

Cytokinesis

Back 39

Completion step of mitosis
Intiated in late anaphase
Triggered by inactivation of MPF
Contraction of actin-myosin filaments

Front 40

Result of mitosis

Back 40

Diploid daughter cells
Identical genetic components

Front 41

Result of meiosis

Back 41

Haploid daughter cells
Half the number of chromosomes

Front 42

Fertilization

Back 42

Sperm binds to receptor on surface of egg and fuses with egg plasma membrane-->produces a new diploid cell

Front 43

Effect of sperm binding to egg on Ca2+ levels

Back 43

Cytoplasmic Ca2+ levels increase via hydrolysis of PIP2

Front 44

Effect of increased Ca2+ levels

Back 44

Exocytosis of secretory vesicles leads to surface alterations and blocks entry of additional sperm