Lecture 13: Cell Cycle and Replication

Question 1

How many phases are in the cell cycle? Name them

Answer 1

• there are four phases
• Mitotic (M Phase)
• Interphase (G1 Phase)
• DNA synthesis (S Phase)
• Cell growth (G2 Phase)

Question 2

How can you roughly organize the cell cycle phases?

Answer 2

Into M Phase and Interphase (everything between cell division)

Question 3

When one cell splits, what is the result called?

Answer 3

daughter cells

Question 4

In how many stages of the cell cycle does cell division occur?

Answer 4

one

Question 5

Describe G1 Phase

Answer 5

growth after being newly formed, emphasis on obtaining energy and forming protein.

Question 6

What occurs often in the G1 Phase?

Answer 6

Lots of transcription and translation to make a lot of protein

Question 7

Describe S Phase

Answer 7

Synthesis phase is when the full genome of the organism is copied

Question 8

What do you call the copying of the genome?

Answer 8

Replication

Question 9

Describe G2 Phase

Answer 9

Focuses on further growth and preparation for cell division and production of new organelles and proteins for mitosis

Question 10

What happens in the M Phase?

Answer 10

Mitosis and cytokinesis

Question 11

Describe Mitosis and Cytokinesis (General)

Answer 11

when the cell actually splits its DNA copies along the cytosol between the cells

Question 12

What is the G0 Phase?

Answer 12

a pause to the cell cycle, when they stop growing and just live

Question 13

How much time can the cell stay in the G0 Phase? Give an example

Answer 13

• they can stay there all of their life

- neurons

Question 14

Is a cell in the G0 Phase alive?

Answer 14

yes, just not dividing anymore

Question 15

How do you regulate the cell cycle?

Answer 15

with checkpoints

Question 16

What do checkpoints in a cell ensure and what does it avoid?

Answer 16

• ensures that it is ready for the next stage

- avoids mitosis without enough DNA, cytosol or organelles

Question 17

What type of cell doesn’t care for the cell cycle?

Answer 17

Cancer cells

Question 18

What is replication and what phase does it belong to in the cell cycle?

Answer 18

• replicating DNA

- the S phase

Question 19

What is replication similar to?

Answer 19

Transcription, but on both strands at the same time

Question 20

What must always happen in replication?

Answer 20

there must be a permanent separation of two strands of DNA

Question 21

Is each new DNA molecule completely new?

Answer 21

No, they all have an old half and a new half

Question 22

How many steps are in replication? name them

Answer 22

• there are two steps
• Step 1: separating the two strands of DNA
• Step 2: use both DNA strands as templates

Question 23

What does step 1 of replication do to the DNA strands?

Answer 23

a permanent separation

Question 24

What do the separation stretches create in replication?

Answer 24

The Replication Fork

Question 25

What is the major protein involved in step 2 of replication?

Answer 25

DNA Polymerase

Question 26

What does DNA Polymerase do in step 2 of replication?

Answer 26

It attaches to each strand and use it to produce the complimentary strand

Question 27

What are the strands referred to as in replication? Do they have a difference in speed?

Answer 27

Leading and lagging strands, the leading one is copied faster

Question 28

Is there only one protein involved in replication?

Answer 28

No, there are many

Question 29

When can errors occur?

Answer 29

during replication or during the life of the cell

Question 30

Can errors be passed on to offspring?

Answer 30

Yes, there is a chance, if the mutation is in the gamete

Question 31

What do you call an error in the genome?

Answer 31

Mutation

Question 32

Are all mutations fatal?

Answer 32

No, they can be unimportant to survival

Question 33

What is involved in DNA repair?

Answer 33

Proteins | that find mistakes, remove mistakes and then refill the removed nucleotides

Question 34

What happens if there isnt any repairs done?

Answer 34

genetic mutations arise

Question 35

How is the DNA normally organized?

Answer 35

uncondensed in the nucleus, a bundle of 46 DNA molecules

Question 36

Are the DNA copies identical? What are they called?

Answer 36

No, but they are very similar and are called homologous chromosome

Question 37

When do the chromosomes compact?

Answer 37

when cell division is about to begin

Question 38

When are the chromosomes clearly visible?

Answer 38

when the cell division is about to begin

Question 39

When do you have 92 DNA molecules in the nucleus?

Answer 39

after S phase

Question 40

how many chromosomes are there after S phase?

Answer 40

46

Question 41

What are the identical copies called after S phase?

Answer 41

sister chromatids

Question 42

How many chromosomes are in one X shaped structure seen in diagrams?

Answer 42

2

Question 43

Define the centromere and where it is located.

Answer 43

A region of a the chromosome where it can attach to its sister chromatid.

Question 44

What is the kinetochore?

Answer 44

a protein that holds the centromere onto the cell's microtubules