mitosis & meiosis

Question 1

What important events occur during interphase to set the cell up for successful M phase?

Answer 1

-advancement through check points
-duplication of centrosome
-DNA replication
-chromosomes begin being loosely packed

Question 2

What is the G0 phase for?

Answer 2

it is a mechanism by which specialized tissues control where and when its cells divide. basically for cells that do not want to replicate

Question 3

which checkpoint is critical for inhibiting cancer?

Answer 3

G2

Question 4

biochemical circuits that can detect either external or internal problems and in response to these, will inhibit the cell cycle

Answer 4

checkpoints

Question 5

the core components of the cell cycle clock and represent the cellular signals used to transition from one phase to the next

Answer 5

cyclins and cyclin dependent kinases

Question 6

when does centrosome duplication begin and end?

Answer 6

begins in S phase but ends in G2

Question 7

what are the 5 stages of mitosis?

Answer 7

prophase
prometaphase
metaphase
anaphase
telophase

Question 8

what two proteins regulate the condensation of chromosomes?

Answer 8

-cohesin ties the sister chromatids together
-condesin packs the DNA coils tightly

Question 9

at what point do the chromosomes condense into observable forms in the microscope?

Answer 9

prophase

Question 10

what happens at prophase?

Answer 10

-chromosomes condense
-outside the nucleus, mitotic spindle assembles between the two centrosomes

Question 11

what happens at prometaphase?

Answer 11

-the nuclear envelope breaks down
-chromosomes attach to spindle microtubules via their kinetochores and undergo active movement

Question 12

what could cause a cell to arrest at prometaphase?

Answer 12

if the sister chromatids are not contacted by spindle fibers of BOTH pairs of centrosomes

Question 13

what happens at metaphase?

Answer 13

-the chromosomes are aligned at the equator of the spindle, midway between the spindle poles
-the kinetochore microtubules attach sister chromatids to opposite poles of the spindle

Question 14

what are the 3 classes of microtubules within the fully formed mitotic spindle and what are their functions?

Answer 14

-astral: anchor
-kinetochore: attach to chromatids and pull
-overlap: attach to each other and push

Question 15

what happens during anaphase?

Answer 15

-sister chromatids separate to form two daughter chromosomes and each is pulled slowly toward the spindle pole it face
-kinetochore microtubules get shorter and spindle poles move apart

Question 16

what triggers the metaphase to anaphase transition?

Answer 16

anaphase promoting complex

Question 17

when are chromatids considered daughter chromosomes?

Answer 17

once they are separated

Question 18

coordinated disassembly of kinetochore microtubules and action of ________________allow progression of chromosomes toward spindle poles?

Answer 18

Dyneins

Question 19

Kin1 acts as a ?

Answer 19

microtubule disassemblase

Question 20

a component of kinetochores that is +end directed motor critical for initial metaphase chromosomal alignment

Answer 20

Centromere protein E (CENP-E)

Question 21

+end directed motors associated with the chromosomal arms and drive the arms away from the pole, producing the chromosomal ejection force

Answer 21

chromokinesins

Question 22

what happens at telophase?

Answer 22

-the two sets of daughter chromosomes arrive at the poles of the spindle and decondense
-a new nuclear envelope assembles around each set, completing the formation of two nuclei and marking the end of mitosis

Question 23

the division of cytoplasm begins with the assembly of what?

Answer 23

the contractile ring

Question 24

what happens during cytokinesis?

Answer 24

the cytoplasm is divided in two by a contractile ring of actin and myosin filaments, which pinches the cell in two to create two daughters with one nucleus

Question 25

not captured by the kinetochore microtubules and are therefore randomly distributed into the daughter cells at cytokinesis

Answer 25

extrachromosomal DNA

Question 26

what is the goal of meiosis?

Answer 26

to produce haploid cells with genetic variation

Question 27

what are the 5 subphases of meiosis I?

Answer 27

leptotene
zygotene
pachytene
diplotene
diakinesis

Question 28

during what phase does crossing over occur

Answer 28

pachytene

Question 29

where the exchange of genes in a crossover event take place

Answer 29

chiasmata