chromosomes, the cell cycle and cell division

Question 1

unicellular organisms vs multicellular organisms with cell division

Answer 1

unicellular organisms- reproduce
multicellular organisms - cell division for growth and tissue repair

Question 2

replication

Answer 2

Replication of genetic material (DNA) is important; such that two new cells
have identical genes and complete cell function

Question 3

segregation

Answer 3

The cell must distribute the DNA to each of the two cells.

.the ori begins to move to opposite ends of the cell. Ori
also binds proteins that hydrolyze ATP. The cytoskeleton may be involved in actively moving DNA along or passively acting as “railroad tracks”

Question 4

cytokinesis

Answer 4

New materials must be added to the cell membrane (or cell wall for cells
that have them) the process of separating two new cells

.when chromosome replication is finished, cytokinesis
begins. The cell pinches inward and tubulin helps to separate the two cells (tubulin makes up microtubules)

Question 5

prokaryotes reproduce by what

Answer 5

binary fission

Question 6

binary fission

Answer 6

The cell grows, replicates its genetic material, and divides into two new cells

Question 7

how can replication e sped up

Answer 7

more nutrients

Question 8

chromosome

Answer 8

DNA molecule containing genetic information
. highly compacted

Question 9

prokaryotes vs eukaryotes

Answer 9

pro :
.one chromosome
.constantly divide
. cytokinesis can only occur following duplication of the entire nucleus
euk :
.cell divides by mitosis or meiosis
.do not constantly divide
.many chromosomes
.distinct nucleus (divide into nuclei )

Question 10

Gametes

Answer 10

sex cells derived from the organisms’ parents

Question 11

meiosis

Answer 11

occurs only in cells that produce gametes (only in cells that produce
sperm and egg)

Question 12

how is eukaryotic cell division controlled ?

Answer 12

reproduce sexually

Question 13

cell cycle

Answer 13

the events that produce two cells from one

Question 14

M phase describe it

Answer 14

mitosis and cytokinesis - - cell division occurs there . during mitosis nuclear division occurs

Question 15

interphase

Answer 15

when the cell is most of their life.

Question 16

what 2 phases are in the cell cycle

Answer 16

mitosis(M) and interphase

Question 17

G1

Answer 17

represents the end of mitosis and the
beginning of S phase. G1 or gap phase 1

Question 18

S phase

Answer 18

DNA synthesis and DNA is replicated

Question 19

G2

Answer 19

separates the end of S phase and
the beginning of Mitosis

Question 20

more on G1

Answer 20

this phase varies on cell types. some rapidly dividing cells do not have this phase while some remain in G1 for weeks to years

Question 21

what is the term used when G1 to S transition

Answer 21

commitment step

Question 22

during G2 what must happen

Answer 22

cell must synthesize microtubules that will move sister chromatids to opposite ends of the dividing cell

Question 23

cyclin

Answer 23

dependent kinase or cdks are
proteins that facilitate cell cycle transitions

. cyclin
activates cdk by altering its shape and
exposing the active site. It is the cyclin-cdk
complex that acts as a kinase and triggers
transition from G1 to S phase

Question 24

what is the key to get through restriction zones

Answer 24

RB

Question 25

what is RB

Answer 25

protein kinase that normally inhibits progression of the cell cycle, however when RB is phosphorylated, RB is inhibited

Question 26

p21 what is it

Answer 26

it is made when DNA is damaged . it can bind to G1 ro prevent action . breaks down when DNA is prepared . tumor suppressors

Question 27

what are the three tumor suppressors

Answer 27

p53 , p21 and RB

Question 28

Growth factors

Answer 28

If cells are to divide, they must be stimulated by signals called growth factors

Question 29

chromatin

Answer 29

Eukaryotic chromosomes have tow gigantic linear double stranded molecules of DNA complexed around many proteins into dense material

Question 30

chromatids

Answer 30

Before S phase there is only one double stranded DNA molecule but after S phase there are two double strands sister chromatids

Question 31

cohesions

Answer 31

DNA is held together by protein complexes

Question 32

centromere

Answer 32

They stay together until the cohesion is removed, except in a region called the centromere

Question 33

condensins

Answer 33

a second group of protein .condensins coat the DNA to make it more compact

Question 34

The centrosomes double during S phase to form a pair of

Answer 34

centrosomes

Question 35

centrioles-

Answer 35

a hollow tube lined with microtubules

Question 35

centrioles-

Answer 35

a hollow tube lined with microtubules

Question 36

During the G2

Answer 36

M transition the centrosomes separate and move to opposite ends of the nuclear envelope

Question 37

during interphase what is visible under a light microscope ?

Answer 37

nuclear envelope