Bio Ch 9

Front 1

S phase

Back 1

DNA replication completed; Two sister chromatids joined together waiting to be segregated; "synthesis"

Front 2

G2 phase

Back 2

“gap” end of S phase to beginning of mitosis; Cell prepares for mitosis: i.e. Synthesize microtubules to move chromotids to opposite end of cell

Front 3

Prophase

Back 3

chromosomes condense and centrioles move to centrosomes. Centrioles produce microtubules in radial array.

Front 4

Prometaphase

Back 4

nuclear envelope disintegrates and kinetochore microtubules attach to kinetochore regions of chromosome. Chromosomes move toward poles

Front 5

Polar microtubules

Back 5

(prophase/prometaphase) microtubules that don't attach to kinetochore region. Forms framework of the spindle

Front 6

Metaphase

Back 6

chromosomes line up in middle (equatorial plate) of cell, one on top of the other. Mitotic spindle is fully formed

Front 7

Anaphase

Back 7

sister chromatids become separated and become chromosomes. Separation result of enzyme separase. Poles of spindle move apart as result of microtubules sliding by each other while kinetochore microtubules shorten.

Front 8

Separase

Back 8

Enzyme during anaphase that hydrolyzes cohesin that holds sister chromatids together @ centromere.

Front 9

Motor action during anaphase

Back 9

Poles of spindle move apart as result of microtubules sliding by each other while kinetochore microtubules shorten by removal of tubulin units. Motor proteins aid in motion of chromosomes.

Front 10

Telophase

Back 10

chromosomes reach poles. Nuclear envelope reforms around chromosomes. Chromosomes unwind.

Front 11

Cytokinesis in animals

Back 11

cleavage furrow (outside-in)--drawstring pull. Contraction of actin and myosin.

Front 12

Cytokinesis in plants

Back 12

cell plate formed (inside out). vesicles from Golgi apparatus fuse to form plasma membrane and contents contribute to cell plate.

Front 13

Mitosis in fungi and some protista

Back 13

1st nucleus divides then cell divides. Mitosis occurs within nucleus.

Front 14

What are the 4 main checkpoints in regulating cell cycle?

Back 14

G1/S, S, G2/M, late metaphase

Front 15

protooncogenes

Back 15

"before stimulate tumors"--genes that receive and respond to growth factors so that mitosis occurs; mutation of these genes may result in mitosis w/out growth factors :(

Front 16

tumor suppressor genes

Back 16

produce products that inhibit mitosis ex.: p21, p53, RB--if these genes don't work, mitosis not inhibited

Front 17

Cyclin-dependent kinase (Cdk)

Back 17

transitions from G1 to S and G2 to M depend on this protein; Cdk-cyclin complexes phosphorylate RB (inhibits the inhibitor of mitosis)

Front 18

Cyclin

Back 18

binds to Cdk’s and alters shape and exposes active site. After cyclins are produced, they're destroyed.

Front 19

Retinoblastoma protein

Back 19

normally inhibits cell cycle but when phosphorylated by protein kinase (Cdk-cyclin) becomes inactive and no longer blocks restriction point—G1—S phase

Front 20

p21

Back 20

gene that checks if DNA is damaged. Triggers enzymes to repair DNA by preventing formation of cyclin-cdk complexes. If irreparable, targeted for death.

Front 21

S phase checkpoint

Back 21

see if DNA properly replicated

Front 22

G2/mitosis

Back 22

check if preparations for mitosis completed

Front 23

metaphase

Back 23

check if all chromosomes attached to mitotic spindle

Front 24

growth factors

Back 24

in animals- stimulates cell division (even leave G0); they're usu. short peptides

Front 25

another word for fertilization

Back 25

syngamy

Front 26

meiosis

Back 26

cut # of chromosomes in half by cell division.

Front 27

"diplontic life cycle"

Back 27

only haploid cells are the ones produced by meiosis--animals

Front 28

"haplontic life cycle"

Back 28

most protists and many fungi: 2n stage is zygote which produce 1n spores which divide mitotically into organism--differentiates into sperm and egg

Front 29

sexual life cycle of plants

Back 29

alternating generations from gametophyte (1n) to sporophyte (2n)

Front 30

gametophyte and sporophyte

Back 30

(1) produces gametes by mitosis and (2) produces spores by meiosis

Front 31

Meiosis I function

Back 31

To reduce chromosomes by 1/2

Front 32

Meiosis II function

Back 32

create 4 daughter cells

Front 33

Prophase I

Back 33

homologous chromosomes undergo synapsis and crossing over of genetic material

Front 34

tetrads or bivalents

Back 34

4 chromatids or two chromosomes (describes homologous pairs undergoing synapsis)

Front 35

chiasmata

Back 35

crossing over and exchange parts of non-sister chromatids

Front 36

prometaphase I

Back 36

nuclear envelope fragments

Front 37

Metaphase I

Back 37

homologs line up on middle plate; maternal and paternal pairs align randomly (which way they face)

Front 38

Anaphase I

Back 38

homologous chrom. separate from each other--random arrg. basis of independent assortment

Front 39

Telophase I

Back 39

segregation of chromosomes into 2 clusters

Front 40

cytokinesis

Back 40

division of cell (usually)

Front 41

Aneuploidy

Back 41

wrong number of chromosomes--nondisjunctions during meiosis

Front 42

nondisjunctions in anaphase I

Back 42

2 gametes = n + 1
2 gametes = n - 1
i.e. two chromosomes in one side and 0 in the other

Front 43

nondisjunctions in anaphase II

Back 43

1 gamete = n + 1
1 gamete = n - 1

Front 44

trisomic

Back 44

n + 1 gamete creates 2n + 1 zygote--zygote is trisomic for a chromosome

Front 45

monosomic

Back 45

n - 1 gamete, 2n - 1 zygote

Front 46

necrosis

Back 46

cell killed by damage or starvation

Front 47

apoptosis

Back 47

programmed cell death--cell no longer needed or prone to genetic damage

Front 48

instances of apoptosis

Back 48

fetal development (webbed hands), respiratory tract and digestive tract (cells replaced every two weeks to kill off tumors)