mitosis meiosis

Question 1

what four events must occur for cell division?

Answer 1

1. reproductive signal
2. replication of dna
3. segregation of dan into two new cells
4. cytokinesis: separation of the two new cells

Question 2

binary fission

Answer 2

result in two new cells

Question 3

what are external factors

Answer 3

nutrient concentration and environmental conditions are the reproductive signals that initiate cell division

Question 4

most have one circular chromosomes:

Answer 4

two regions: ore and ter

Question 5

Ori and ter

Answer 5

replication begins s ori and proceeds in both directions towards ter

Question 6

what is the cell cycle?

Answer 6

period between cell divisions, divided into mitosis/cytokinesis and interphase.

Question 7

interphase:

Answer 7

cell nucleus in visible and cell function including replication occur.

Question 8

when does interphase happen?

Answer 8

begins after cytokinesis and ends when mitosis starts.

Question 9

three sub phases of interphase:

Answer 9

G1, S, G2

Question 10

G1; Gap 1-

Answer 10

cell growth

Question 11

restriction point:

Answer 11

at the G1 to S transition a commitment is made to DNA replication and cell division

Question 12

S phase:

Answer 12

DNA replicates; one chromosome becomes two sister chromatids

Question 13

G2: Gap 2

Answer 13

cell prepares for mitosis

Question 14

M phase:

Answer 14

mitosis and cytokinesis occur during this phase

Question 15

Dna molecule is complexed with proteins to form dense:

Answer 15

chromatin

Question 16

what holds sister chromatids togethers?

Answer 16

centromere

Question 17

what does dna packed during interphase with positively charged histones?

Answer 17

result in nucleosomes

Question 18

centrosome

Answer 18

determines the plane of cell division

-doubles during s phase and will determine spindle orientation

Question 19

each centrosome consists of two:

Answer 19

centrioles

Question 20

when do centrosomes migrate to the opposite ends of cells?

Answer 20

during G2 M transition

Question 21

What are the phases of mitosis?

Answer 21

Prophase 
Pro metaphase 
Metaphase 
Anaphase 
Telophase

Question 22

Prophase:

Answer 22

nuclear membrane startes to disappear
-chromosomes begin to appear
-kinetochores develop in centromere regions
-

Question 23

Pro metaphase

Answer 23

nuclear envelope disappears
- chromosomes consisting of two chromatids attach to kinetochore microtubules-
spindle fibers appear

Question 24

metaphase:

Answer 24

chromosomes are lines up at the midline of the cell

Question 25

anaphase:

Answer 25

separation of sister chromatids

-spindle fibers (microtubules) shorten and move chromatids to opposite ends of spindle

Question 26

telophase:

Answer 26

chromosomes uncoil, spindle breaks down

nuclear envelopes begin to form

Question 27

cytokinesis

Answer 27

divison (pinching off) of the cells

-differs in plants and animals

Question 28

cytokinesis in animal:

Answer 28

plasma membran pinches between the nuclei- contractile ring of microfilaments of actin and myosin

Question 29

cytokinesis in plant cells:

Answer 29

vesicles from golgi apparatus appear along the plane of cell division - fuse to form new plasma membrane (cell plate)