cell division

Question 1

why do cells go through mitosis?

Answer 1

growth, replacement of cells, differentiation

Question 2

what is the order of the cell cycle events?

Answer 2

interphase, m-phase, cytokinesis

Question 3

what happens in G0?

Answer 3

G0 is the resting state, where the cell does its cell job

Question 4

what is chromatin?

Answer 4

uncoiled DNA that is invisible under the microscope, found during interphase

Question 5

what is a double chromosome?

Answer 5

two sister chromatids made up of DNA coiled around histones, in which each sister chromatid is held together by a centromere, found during prophase and metaphase

Question 6

what is a chromosome?

Answer 6

when the two sister chromatids separate, found during anaphase and telophase

Question 7

what happens during G1 and G2 of interphase?

Answer 7

when the cells make the proteins, grow, and pass through checkpoints; cell part needed for division are made (centrioles)

Question 8

what happens during S of interphase?

Answer 8

when DNA replicates in between G1 and G2

Question 9

what is checked during G1?

Answer 9

growth factors and DNA damage

Question 10

what is checked during metaphase?

Answer 10

whether the spindle fibers attached to the centromeres properly

Question 11

what is checked during G2?

Answer 11

the cell size and whether the DNA replicated correctly

Question 12

what is the order of mitosis?

Answer 12

interphase, prophase, metaphase, anaphase, telophase (IPMAT)

Question 13

what happens during prophase?

Answer 13

chromatin coils up, condensing into double chromosomes; the nuclear envelope disappears; the centrioles migrate towards the poles; the spindle begins to form and the fibers attach to the centromeres of the sister chromatids

Question 14

what happens during metaphase?

Answer 14

the doubled chromosomes line up at the equator of the cell moved by the spindle fibers attached to their centromere

Question 15

what happens during anaphase?

Answer 15

the centromeres split, separating the sister chromatids; the spindle fibers pull the identical chromosomes towards the opposite poles

Question 16

what happens during telophase?

Answer 16

opposite of prophase: the chromosomes uncoil; the nuclear envelopes reappear, the spindle fibers break down, disappearing; the cytoplasm begins to divide

Question 17

what happens during cytokinesis?

Answer 17

division of the cytoplasm: in animal cells, the plasma membrane pinches causing a cleavage furrow; in plant cells, a cell plate develops and secretes a new cell wall

Question 18

what are proto-oncogenes?

Answer 18

genes that produce proteins that promote cell division; when mutated, will overwork and lead to cancer (like a foot on the accelerator)

Question 19

what are suppressor proteins?

Answer 19

an example is p53; it prevents cells with DNA problems to replicate; when mutated, it will not stop cells even if there is damaged DNA, and will lead to cancer (like removing the brakes)

Question 20

which nucleotides are purines?

Answer 20

Adenine and Guanine (AG)

Question 21

which nucleotides are pyrimidines?

Answer 21

Cytosine and Thymine (CT)

Question 22

which end of the DNA has a phosphate?

Answer 22

the 5’ side

Question 23

which end of the DNA has a deoxyribose?

Answer 23

the 3’ side

Question 24

how many hydrogen bonds are between A and T?

Answer 24

2

Question 25

how many hydrogen bonds are between C and G?

Answer 25

3

Question 26

when does DNA replication occur?

Answer 26

the S phase of interphase (before mitosis)

Question 27

which enzyme unzips the DNA?

Answer 27

helicase (helio=sun=unzip)

Question 28

which enzyme builds the new DNA strands?

Answer 28

DNA polymerase

Question 29

which enzyme glues the Okazaki fragments back together?

Answer 29

ligase (liga=ligament=connectors)

Question 30

what direction do nucleotides get added?

Answer 30

5’ to 3’