Cell movement and division

Question 1

where are Intermediate filaments present?

Answer 1

in cytoplasm and nucleus

Question 2

Intermediate filaments structure

Answer 2

strong but flexible
alpha helical coil
protein subunits = lamins
lines inner face of nuclear membrane

Question 3

microtubules structure

Answer 3

globular polymers
rigid and unstable
in cytoplasm, grows from centrosome
polar structure - alpha - and beta + ends

Question 4

microtubules function

Answer 4

segregation of chromosomes in mitosis
organelle shuttling
facilitate movement
organising centre for chromosomes in mitosis

Question 5

microtubule assembly points

Answer 5

centrosome in normal cell
spindle fibres in dividing cell
basal body in cilia or flagella

Question 6

cilia vs flagella

Answer 6

cilia - numerous and short, flip back and forth to push material across surface
flagella - few and long, cause locomotion

Question 7

actin filaments structure

Answer 7

polymers - actin monomers use ATP to build

Question 8

formation of actin filaments

Answer 8

filament polarised
G-actin monomers added to each end
polymerisation associated with ATP hydrolysis
filament assembly and organisation regulated by interactions with actin binding proteins

Question 9

actin filaments as motor proteins

Answer 9

globular heads bind ATP
hydrolysis of ATP drives movement
tails bind structures like plasma membrane
can move cells/cellular components

Question 10

quiescence definition

Answer 10

pause in cell cycle

Question 11

apoptosis definition

Answer 11

programmed cell death

Question 12

necrosis definition

Answer 12

accidental cell death

Question 13

mitosis prophase

Answer 13

chromosomes condense

mitotic spindles begin to form

Question 14

mitosis prometaphase

Answer 14

breakdown of nuclear membrane

chromosomes attach to microtubules

Question 15

mitosis metaphase

Answer 15

chromosomes align at equator

spindle starts to pull chromatids

Question 16

mitosis anaphase

Answer 16

spindles become shorter and pull chromatids to poles

Question 17

mitosis telophase

Answer 17

nuclear membrane reassembles

contractile ring contracts, cell splits

Question 18

mitosis interphase

Answer 18

G1 - main growth, recovery from cytokinesis
S - DNA synthesis
G2 - preparation for mitosis

Question 19

g1 checkpoint

Answer 19

cell size
favorable environment
DNA damage

Question 20

g2 checkpoint

Answer 20

has DNa replicated correctly

is environment still favorable

Question 21

m checkpoint

Answer 21

are all chromosomes attached to spindle

Question 22

cyclin dependent kinases (CDKs)

Answer 22

kinesins = enzymes that add a phosphate group from ATP to an amino acid in a protein
CDKs are inactive unless a cyclin binds
cyclins are destroyed throughout cycle

Question 23

apoptosis

Answer 23

regulated process, programmed
built in suicide pathways
cell shrinks, nucleus condenses, membrane changes
apoptotic bodies digested and recycled

Question 24

necrosis

Answer 24

accidental death due to injury

nuclear swelling leads to lysis

Question 25

why is apoptosis triggered?

Answer 25

remove tissue
maintain homeostasis
pathogenic activation

Question 26

p53 function apoptosis

Answer 26

upregulates apoptosis genes