CH 10.3 Overview of Eukaryotic Cell Cycle

Question 1

What does the Cell Cycle require?

Answer 1

• Duplication of Genome
• Accurate segregation
• Division of Cellular Contents

Question 2

What are the 5 phases of the Cell Cycle?

Answer 2

• G1 (gap phase 1)
• S (synthesis)
• G2 (gap phase 2)
• Mitosis
• Cytokinesis

Question 3

What occurs in the G1 phase of the Cell Cycle?

Answer 3

• AKA gap phase 1 & Pre Replication
• This is the primary growth phase & is where the cell carries outs its regular metabolic activity
• It is also the LONGEST phase

Question 4

What does “Gap Phase” mean?

Answer 4

-It refers to its filling of the gap between cytokinesis & DNA synthesis

Question 5

What occurs in the S phase of the Cell Cycle?

Answer 5

• AKA Synthesis
• This is where the cell synthesizes a replica of genome
• The centrosome also replicates here

Question 6

What occurs in the G2 phase of the Cell Cycle?

Answer 6

• AKA gap phase 2 & Post-Replication
• This is the 2nd growth phase= cell prepares for segregation & cell division
• It also fills the gap between DNA synthesis & beginning of mitosis
• Microtubules begin to form into a spindle
• Chromosomes coil tigher

Question 7

What do G1, S, and G2 make up?

Answer 7

-They all makeup Interphase which is the portion of the cell cycle BETWEEN divisions

Question 8

What occurs in the Mitosis phase of the Cell Cycle?

Answer 8

-The spindles assemble & bind to chromosomes which moves the sister chromatids apart= DNA segregation

Question 9

What are the 5 stages of Mitosis?

Answer 9

• Prophase
• ProMetaphase
• Metaphase
• Anaphase
• Telophase

Question 10

What occurs in the Cytokinesis phase of the Cell Cycle?

Answer 10

-The cytoplasm divides= forms 2 independent daughter cells

Question 11

What occurs in the Cytokinesis phase of the Cell Cycle in ANIMALS?

Answer 11

• The microtubule spindle helps position a contracting ring of actin that pinches the cells in 2
• Looks like those fruits where its pucked in the middle at the mexican tienda

Question 12

What occurs in the Cytokinesis phase of the Cell Cycle in PLANTS?

Answer 12

-A cell plate made up of lined up membranes forms in between the cells

Question 13

How long does the Cell Cycle take to complete in animals?

Answer 13

-under 20 mins

Question 14

What animal has the shortest cell division time?

Answer 14

-Fruit flys embryos= 8min

Question 15

What is G0 phase?

Answer 15

-It is the non-dividing phase that G1 cells often take a pause in before DNA replication

Question 16

What are the 4 levels of compaction?

Answer 16

• Nucleosome= DNA wrapped around a histone protein
• Solenoid=Froms the chromatin= associated w/ interphase
• Chromatin Loop
• Rosettes of Chromatin loops= forming rosettes on scaffold proteins= highly condensed DNA

Question 17

What controls 3 things Cell Cycle?

Answer 17

• Cyclins
• Kinases
• MPF

Question 18

What are Cyclins?

Answer 18

-Regulatory proteins that INCREASE going INTO mitosis & DECREASE going OUT

Question 19

What are Kinases?

Answer 19

-They are enzymes that phosphorylate other molecules= add a phosphate group to them so they can work

Question 20

What is MPF?

Answer 20

• AKA Maturation- Promoting Factor

- It is the Cyclin-Cdk complex= depends on the amount of Cyclin at a certain time

Question 21

What is Cdk?

Answer 21

-It is Cyclin Dependent Kinases= constant in the cell cycle but won’t work w/o cyclin

Question 22

Why are Checkpoints of the Cell Cycle necessary?

Answer 22

• To make sure that the cell has its necessary nutrients & that there isn’t damage detected
• If the cell doesn’t pass the checkpoint, the cell cycle comes to a stop

Question 23

What are the 3 checkpoints of the Cell Cycle?

Answer 23

• Start/ Restriction point= G1/s
• Metaphase
• Anaphase