cell division (mitosis and meiosis)

Question 1

stem cells

Answer 1

can use to repair cellular loss/damage

most tissues retain a population of stem cells

Question 2

terminally differentiated cells

Answer 2

lose the ability to undergo mitosis

cannot create more cells but have continuous differentiated function

enter G0

Question 3

facultative dividers

Answer 3

can switch between doing it’s job and making more cells

Question 4

G0 phase

Answer 4

cells that lose the capacity for cell division enter an extended G0 phase

can be permanent (terminally differentiated) or reversible (facultative dividers)

Question 5

Mitosis phases

Answer 5

interphase

prophase -> prometaphase (end of prophase)

metaphase

anaphase

telophase

Question 6

interphase

Answer 6

resting phase

time between divisions

occupies most of a cell’s life

subphases = G1 S G2

Question 7

G1

Answer 7

1st and longest gap phase
last hours to days

Question 8

hypertrophy

Answer 8

increase in cell size

occurs in G1

Question 9

hyperplasia

Answer 9

increase in cell number

occurs during mitosis

Question 10

S phase

Answer 10

= synthesis

replication of DNA -> starts at 2n ends at 4n

following replication each chromosome contains 2 chromatids connected by centromere (sisters chromatids)

Question 11

G2

Answer 11

second gap phase

preparation for mitosis

synthesis of ATP

synthesis of tubulin for mitotic spindle

Question 12

3 checkpoints for mitosis

Answer 12

1. G1 checkpoint = end of G1 phase

determines if cell is big enough / has proper proteins for S phase
if not cell enter G0

2. DNA synthesis checkpoint = during S phase

checks for correct DNA replication -> continues to M (mitosis)

3. Mitosis Checkpoint = during mitosis (M phase)

checks for completed mitosis

if so cells divides and repeats cell cycle

Question 13

M phase

Answer 13

cell division portion of mitosis

charactered by karyokinesis followed by cytokinesis

creates 2 daughter cells that are as identical as possible

Question 14

karyokinesis

Answer 14

division of nucleolus

Question 15

cytokinesis

Answer 15

division of cytoplasm

Question 16

when do chromosomes condense in cell cycle

Answer 16

during S & M phases

chromosomes become visible and look like coiled snakes

Question 17

when are chromosomes an unraveled mass

Answer 17

G1 & G0

Question 18

prophase

Answer 18

first phase

chromosomes visibly condensed / not necessarily organized

microfilaments and microtubules of cytoskeleton disaggregate

centrioles migrate to poles of cell and form spindle apparatus with interpolar microtubules

Question 19

prometaphase

Answer 19

late prophase

nuclear membrane and nucleoli gone

mitotic spindle attaches to chromosomes at kinetochore

Question 20

metaphase

Answer 20

chromosomes line up along metaphase plate

Question 21

anaphase

Answer 21

centromere split apart

chromosomes migrate to opposite ends of cell

pulled by microtubules connecting centriole and kinetochore

*Dr. M. Cole’s favorite phase

Question 22

mitotic spindle

Answer 22

controls distribution of chromosomes in daughter cells

Question 23

how do chromosomes move

Answer 23

through the addition and subtraction of tubulin subunits and attachment proteins (dynein and kynesin) to chromatids

Question 24

Telophase

Answer 24

mitotic spindle disaggregates

nuclear envelope reassembles / nucleoli reappears

plasma membrane forms cleavage furrow

cytokinesis begins

Question 25

Mitotic index

Answer 25

count # of cells going through mitosis used to describe proportion of cells in a tissue in mitosis at any given time important in tumors

Question 26

Meiosis

Answer 26

reduction division = makes cells with half genetic info haploid gametes for egg and sperm cells occurs only in germ cells of gonads male = spermatogenesis female = oogenesis

Question 27

fusion of gametes

Answer 27

produces a diploid zygote (fertilized egg)

Question 28

First meiotic division

Answer 28

w/ pro- meta- ana- and telophase results in formation of 2 daughter cells

Question 29

how meiosis different from mitosis

Answer 29

during prophase 1 homolgoous pairs of chromosomes form tetrads and exchange chromatin through crossing over results in hybrid chromatids different from parents end of meiosis = 4 haploid gametes

Question 30

Second meiotic division

Answer 30

brief interphase II NO DNA replication NO crossing over during prophase II Anaphase II centromeres spilt Telophase II cytokinesis yields four haploid gametes EACH UNIQUE

Question 31

how many viable gametes produced by gametogenesis

Answer 31

male = 3 or 4 viable gametes female = 1 functional gamete (ovum) 2 or 3 non functional polar bodies

Question 32

spermatogenesis begins

Answer 32

at puberty

Question 33

oogenesis begins

Answer 33

during fetal development female germ cells enter prophase I 5th month of gestation and stop remain in prophase I until ovulation (12-50 year)

Question 34

apoptosis

Answer 34

cell death

Question 35

triggers of apoptosis

Answer 35

timing in fetal development some cells have predetermined life spans (skin cells ; GI tract) growth and regression of ovarian follicles destruction of virus / tumor infected cells clonal deletion in thymus = removal of t cells that react to self molecules

Question 36

failure of clonal deletion

Answer 36

may lead to autoimmune diseases

Question 37

Apoptosis begins with

Answer 37

pyknosis = the shrinkage of nucleus and condensation of nuclear chromatin

Question 38

Autolysis

Answer 38

lysosomes release catalytic enzymes into the cytoplasm

Question 39

when a cell is apoptosis-ing what color does it become

Answer 39

bright pink / eosinophilic

Question 40

the final pathway of apoptosis is initiated by ____

Answer 40

caspace cascade normally inactive enzymes are turned on to help with degeneration and fragmenting the nucleus

Question 41

Karyolysis

Answer 41

chromatin in nucleus begins to degenerate

Question 42

karyorrhexis

Answer 42

nuclear material begins to fragment and nuclear membrane disintegrates

Question 43

apoptotic bodies

Answer 43

fragmented nuclear debris (dead) necrotic cells phagocytosed by macrophage and neutrophils

Question 44

necrosis

Answer 44

not natural death death of cells as a result of inflammation traumatic injury or pathology