Cell Cycle, Mitosis, and Meiosis

Question 1

big difference between mitosis and meiosis

Answer 1

mitosis - start with diploid & end with diploid

meiosis - start with diploid & end with haploid

Question 2

cell cycle divided into…?

Answer 2

interphase and mitosis

Question 3

time spent in interphase and mitosis

Answer 3

interphase: 20-22 hours until cell is ready to divide
mitosis: 2-4 hours when cell is actually dividing

Question 4

what are the types of cells

Answer 4

labile, permanent, and stable cells

Question 5

what are labile cells and examples?

Answer 5

labile cells can multiply throughout lifespan

ex: skin, GIT, epithelial

Question 6

cells that are quiescent (G0) and only divide when appropriately stimulated

Answer 6

stable cells

ex: liver cells

Question 7

what are permanent cells and example?

Answer 7

cells that have lost the capacity to divide hence permanently remain in G0 phase

ex: cardiac, neurons

Question 8

stages of interphase

Answer 8

G1, S, and G2

Question 9

what happens in G1 phase

Answer 9

new formed cells increase in size, protein synthesis, cell differentiation, cell checked if ready for division

Question 10

what happens to some cells after G1 phase

Answer 10

they (stable and permanent) enter G0 phase

only stable can come out of G0 phase

Question 11

what happens in S phase

Answer 11

DNA synthesis and DNA replication

so entire chromosome is replicated hence end up with double the amount of chromatids

Question 12

what happens in G2 phase

Answer 12

chromatid doubled; cell increases to help formation of two new daughter cells; scanned for mistakes; post DNA rep mechanisms active

Question 13

where are the checkpoints in cell cycle?

Answer 13

G1 checkpoint, G2 checkpoint, and spindle assembly checkpoint in mitosis

Question 14

what proteins are important at the G1 checkpoint (from G1 to S)

Answer 14

p53 and Rb

Question 15

regulate the entry of cells into various phases of the cell cycle

Answer 15

cyclins

Question 16

what happens if damage is found at a checkpoint

Answer 16

cell cycle arrest, DNA repair, or apoptosis

Question 17

signals cells to move through the cell cycle so basically stimulate cell division

Answer 17

growth factors

Question 18

cells have finite lifespan …what is it called when they can no longer divide

Answer 18

senescence

Question 19

what happens when there is a loss of p53 tumor suppressor activity?

Answer 19

proliferation of cells that are damaged under stress conditions –> tumor development

Question 20

chromatid number is doubled at the end of?

Answer 20

interphase specifically S

Question 21

what happens at the end of mitosis?

Answer 21

sister chromatids separated and two daughter cells formed

Question 22

stages of mitosis

Answer 22

Prophase, Metaphase, Anaphase, Telophase, and cytokinesis (cell division)

Question 23

this stage of mitosis - nuclear envelope disappears and chromosome starts to condense and bind to spindles

Answer 23

prophase

Question 24

this stage of mitosis - The microtubules attach to the centromere kinetochores during cell division

Answer 24

metaphase

Question 25

this stage of mitosis - sister chromatid separated and moved to centrioles

Answer 25

anaphase

Question 26

what happens in telophase

Answer 26

sister chromatids moved to opposite poles and nuclear envelope reappears; chromosomes become less condensed

Question 27

how many gametes formed at the end of meiosis

Answer 27

4 (23X or 23Y)

Question 28

difference between meiosis I and meiosis II

Answer 28

meiosis I: homologous chromosomes separate

meiosis II: sister chromatids separate

Question 29

what is homologous recombination and when does it occur

Answer 29

exchange of short fragments of their genetic material

meiosis I

Question 30

importance of meiosis

Answer 30

genetic recombination and genetic diversity

formation of haploid gamete

Question 31

error in the ability of the mitotic

spindle apparatus to pull the chromosome apart

Answer 31

nondisjunction in meiosis

Question 32

difference when nondisjunction occurs in meiosis I vs. meiosis II

Answer 32

meiosis I: homologous chromosomes do not separate

meiosis II: sister chromatids did not separate

Question 33

45X

Answer 33

Turner’s Syndrome

Question 34

47XXY

Answer 34

Klinefelter’s Syndrome

Question 35

45X and 47XXY

Answer 35

all results of nondisjunction

Question 36

undergone all mitotic division of gametes by birth

Answer 36

females

Question 37

difference between male and females at the end of meiosis

Answer 37

male: 4 haploid gametes
female: 1 ovum and three polar bodies

Question 38

phase in which oocytes are arrested during fetal development until ovulation

Answer 38

prophase I of meiosis

Question 39

phase in which oocytes are arrested after ovulation but until it is fertilized

Answer 39

metaphase II of meiosis

Question 40

men spew out how many bad boys during ejaculation

Answer 40

100 to 200 million gametes

Question 41

number of mitoses in gamete formation in females vs. males

Answer 41

males: 30-500
females: 20-30

Question 42

risk if maternal or paternal age is increased

Answer 42

higher chance of nondisjunction

new dominant single gene mutation (man’s fault)

Question 43

A cell division in humans is observed. Cells in culture have their 23 total chromosomes (each composed of two sister chromatids) arranged along the equator of the cell. Which phase of the cell cycle is being observed?

Answer 43

metaphase II of meiosis