Mitosis

Question 1

Checkpoints

Answer 1

“stop” and go-ahead” signals regulate cycle

Question 2

3 checkpoints

Answer 2

G1
G2
M

Question 3

G1 checkpoint

Answer 3

withought the go-ahead; cell goes into G0 sort of like cellular limbo. Functionally, but not dividing, not growing.

Question 4

M checkpoint

Answer 4

kinetochore attachment on all chromosomes to mitotic spindle fibers gives the go-ahead to move from metaphase to anaphase

Question 5

M checkpoint

Answer 5

If the microtubules spindles do not attach properly, cell division dosent occur –> can signal that something is wrong

Question 6

apoptosis

Answer 6

cellular programmed death

Question 7

proliferation

Answer 7

rapid growth and division

Question 8

anchorage dependency

Answer 8

cells require a surface for division

Question 9

Density-dependent inhibition

Answer 9

cells from a single layer, cells divide to fill a gap then stop

Question 10

cancer

Answer 10

cells divide withought listening to typical stop signals; uncontrolled cellular division

Question 11

Benign

Answer 11

dosent spread to other tissues

Question 12

malignant

Answer 12

dangerous, spreads to other tissues

Question 13

metastasis

Answer 13

spread to distant parts of body

Question 14

Henrietta Lacks

Answer 14

she had cervical cancer, during her tumor removal scientists took samples without her consent.

her cells turned out to be immortal - good for growing in a lab

Her cells are called HeLa cells and have had an immeasurable impact on cancer research

Question 15

PDGF

Answer 15

platelet-derived growth factor: made by platelets (cells in bloodstream)
when other cells pick up this growth factor - triggers signal transduction and provides a ‘go-ahead’ signal

Question 16

chromatin

Answer 16

loose coils of DNA wrapped around histone proteins

Question 17

chromosome

Answer 17

tightly coiled chromatin

Question 18

sister chromatid

Answer 18

exact copy, connected at centromere

Question 19

Interphase includes

Answer 19

G1
S
G0

Question 20

Centrosome

Answer 20

region where microtubule precursor aggregate

Question 21

Aster

Answer 21

radial array of short microtubules

Question 22

mitotic spindle

Answer 22

microtubules that move chromosomes

Question 23

kinetochore

Answer 23

protein attachment site on chromosomes fro microtubules

Question 24

G2 Interphase

Answer 24

chromosomes have been duplicated but not yet condensed

Question 25

Prophase (first step of mitosis)

Answer 25

• nuclei disappear
• chromosomes begin to visibly condense
• centrosome move away from each other
• miotic spindle forms

Question 26

Prometaphase (second phase)

Answer 26

• nuclear envelope disintegrates
• chromosomes fully condensed
• microtubules extended and begin to attach to kinetochores

Question 27

Metaphase (third phase)

Answer 27

• chromosomes line up at metaphase plate
• centrosomes are at both poles, microtubules fully attached to kinetochores, spindle extended

Question 28

Anaphase (forth phase)

Answer 28

• shortest phase
• sister chromatids separate
• daughter chromosomes move towards poles
  cell elongates

Question 29

telophase (fifth phase)

Answer 29

• daughter nuclei form
• chromosomes become less condensed
• cleavage furrow forms
• spindles disappear

Question 30

cytokenesis

Answer 30

cytoplasm is divided by cleavage furrow, cell division is complete

Question 31

Binary fission in Prokaryotes

Answer 31

• single circular chromosome
• replicates in opposite directions
• plasma membrane pinches inward