CH 9 Mitosis and Cytokinesis

Question 1

Why do cells divide?

Answer 1

Reproduction
Development
Repair

Question 2

What is mitosis?

Answer 2

Division of chromosomes (Nuclear material)

Question 3

what is cytokinesis?

Answer 3

Physical splitting of single cells into 2

-Division of cytoplasm

Question 4

What does the Eukaryotic cell cycle consist of?

Answer 4

G1
S phase
G2
Mitosis
Cytokinesis

Question 5

What happens in the G1 step of the cell cycle? (1st step) (Gap 1)

Answer 5

Cell is growing/Normal functions

Gap 1 no physical difference

Question 6

What happens in S Phase? (2nd step)

Answer 6

DNA polymerase copies DNA

Question 7

What happens in the G2 step of the cell cycle? (3rd step) (Gap 2)

Answer 7

DNA replication is done and is carrying out functions to prepare for mitosis

Question 8

What happens in Mitosis (4th step of the cell cycle)?

Answer 8

2 copies of DNA move to opposite sides of cell

Question 9

What happens in cytokinesis (5th step)?

Answer 9

Cell physically splits into 2 then are back in G1 phase

Question 10

What are the 4 bases of DNA

Answer 10

Adenine
Thymine
Cytosine
Guanine

Question 11

If you take all DNA in one cell and extend it, how long would it be?

Answer 11

6 Ft

Question 12

When is a chromosome in the “X” structure?

Answer 12

During mitosis (4th step)

Question 13

Why is it necessary to supercoil DNA?

Answer 13

Easier to move around during mitosis
DNA would get snagged and break
Daughter cells wouldn’t have all DNA

Question 14

What does chromatin consist of?

Answer 14

DNA and Histone protein

Question 15

Where is a centromere located?

Answer 15

(Structural) In the center; It is the part of a chromosome that links sister chromatids
-Where chromatids are pinched together

Question 16

What is the difference between chromatin and chromosomes?

Answer 16

Chromatin is unwound DNA that looks like a bowl of spaghetti; Chromosomes are tightly wound DNA in an “X” shape

Question 17

What is a chromatid?

Answer 17

Half of the chromosome

1 of the 2 sides

Question 18

What is a kinetochore?

Answer 18

(Protein) associated with the centromere of a chromosome during cell division

Question 19

What is a telomere?

Answer 19

(Structural) Repetitive nucleotide sequences at each end of a chromosome –Protects the end of the chromosome from deterioration

Question 20

At the end of G2 what does chromatin do?

Answer 20

Condenses into chromosomes

Question 21

What is a nucleosome?

Answer 21

DNA coiled around a core of histones.

Question 22

What are homologous chromosomes?

Answer 22

Set or pair of chromosomes

Same chromosome but different pair

Question 23

What does diploid mean?

Answer 23

2 copies of every chromosome

Question 24

*How do you determine diploid number?

Answer 24

Count number of centromeres

Question 25

What are the phases of mitosis?

Answer 25

Prophase Metaphase Anaphase Telophase

Question 26

1st step of Mitosis is? What happens?

Answer 26

Prophase: - Early phase: Where duplicated chromosomes condense (visually condensed) - Nucleus starts to deteriorate - Late phase: New microtubules assembled; centrioles move to opposite ends

Question 27

2nd step of Mitosis is? What happens?

Answer 27

Metaphase: Middle - Spindle forms and microtubules attach to chromatids - Chromosomes line up at spindle midline

Question 28

3rd step of Mitosis?

Answer 28

Anaphase: Apart - Sister chromatids pulled apart - Once chromatids are separated they are called chromosomes

Question 29

4th step of Mitosis?

Answer 29

Telophase: Two - Cell separates - Chromosomes de-condense (Chromosomes back to chromatin) - Nuclear membranes form - Cell is pinched to prepare for division

Question 30

How do animal and plant cells differ in cytokinesis?

Answer 30

Plants form a cell plate; Animal cells DO NOT

Question 31

Do bacteria and archaea perform mitosis?

Answer 31

No; They participate in prokaryotic fusion

Question 32

What does the ring of microfilaments (in animal cells) do to aid cell division?

Answer 32

From the spindle equator the microfilaments contract and pinch the cells center to split the cell into 2

Question 33

What is G0?

Answer 33

Resting phase of certain cells (i.e) cardiac cells | -Really long 10+ yr G1 Phase

Question 34

Do all Eukaryotic cells perform the cell cycle at the same rate?

Answer 34

No; Skin cells can take 12 hours where cardiac cells cant take 10 yrs

Question 35

What is Interphase?

Answer 35

G1 and G2 different from Mitosis

Question 36

When is DNA in the chromatin phase

Answer 36

G1, S and most of G2

Question 37

In what phase is DNA copied?

Answer 37

S phase

Question 38

When does chromatin condense into chromosomes?

Answer 38

End of G2

Question 39

What is a cell considered when individual chromosomes are visible?

Answer 39

Prophase

Question 40

What is a nucleosome?

Answer 40

DNA wrapped around a histone in a chain that makes of chromatin

Question 41

What are centrosomes/Centrioles?

Answer 41

Look like little cans that form spindles (Protein)