Cell cycle and apoptosis

Question 1

what is mitosis required fro

Answer 1

normal growth development and maintenacne

Question 2

cell cycle properties

Answer 2

ordered set of events leading to growth and divison
- coordinated across different tissues
results in two identical daughter cells
DNA duplicated and divided equalyl

Question 3

main phases in cell cyel

Answer 3

mitotic phase (when cell divided)
interphase

Question 4

what is interphase divided into

Answer 4

G1
2 phase
G2

Question 5

interpahse

Answer 5

chromosomes are formed by condensation of chromatin

nuclear envolpe breaks worn

Question 6

prophase

Answer 6

chromosomes attached to mitotic spindle

Question 7

metaphase

Answer 7

line up at equator

tension on spindle fibres

Question 8

anaphase

Answer 8

chromosomes pulled apart to poles

Question 9

telophase

Answer 9

actin forms here and congrats them to physically divide the cell
cytokinesis physically separates them

Question 10

what are the crital check points of cell cel

Answer 10

G1 G2 M phase

Question 11

which phases influences the cell cycle

Answer 11

s phase

mitotic phase

Question 12

what triggers transitions in the cell cyle and what with

Answer 12

cyclins

cyclin dependant kinases

Question 13

what do cyclins do

Answer 13

trigger cell cycle transititions

Question 14

what happens to the cyclins in cell cyel

Answer 14

levels rise and fall depending on stage of cell cycle

Question 15

clycins correspond to which phase

Answer 15

G1 cyclin (D)
S phase (E and A)
M phase (B and A)

Question 16

what binds to cyclin

Answer 16

cyclin dependant kinases

Question 17

what do cyclin dependant kinases do

Answer 17

phosphorylate proteins that control cell cylle

Question 18

when is cyclin dependant kinase active

Answer 18

when bound to kinase

Question 19

what is cyclin dependant kinase activity controlled by

Answer 19

Cdk inhbitorss

Question 20

cell cycle is regulated by

Answer 20

1) Cyclin and Cdk synthesis

2) Cyclin degradation, Cdk phosphorylation, Cdk inhibition

Question 21

promoting factors for the cell cycle

Answer 21

• cyclin and CDK complex
• eg mitosis promoting factor
• phosphorylates and activates proteins involved in chromatin condensation, nuclear envelope breakdown, spindle assembly

Question 22

when do cyclin levels dall

Answer 22

due to degradation

Question 23

checkpoint G1/s

Answer 23

check for growth factors
nutritional state of cell
size of cell
complex Cdk drives this through

Question 24

s phase

Answer 24

DNA replicated

Question 25

G2 checkpoint

Answer 25

before entering mitotic phase
checks replication is completed
DNA integrityyy

Question 26

anaphase promoting compelx

Answer 26

degrades cyclin
allows cell cycle to complete
makes sure chromosomes are aligned so they separate evenly

Question 27

growth factor extraceullar signals lead to

Answer 27

bind to receptor
strucural change
cascade of phosphorylation
substance enters nucleus
transcription/translation
could lead to product of Vdk

Question 28

what is stage G0

Answer 28

cells permanently or temporaly leave cell cycle

Question 29

what stage are most cells in the body in

Answer 29

G0

Question 30

what can cells do in Go

Answer 30

resting

but can secrete

Question 31

what is terminal differentiation

Answer 31

permanent left cell cycle

Question 32

cell cycle synchronisation

Answer 32

cells can be at different phases

if serum removed and re-added, cells will then start at G1

Question 33

what does dysregualted cell growth lead to

Answer 33

cancer

Question 34

what are many cell regulatory genes involved in

Answer 34

tumour suppressor genes

Question 35

what can chemotherapy taret

Answer 35

DNA replication
mitosis
cytokineis
blood vessel growth

Question 36

what is p53

Answer 36

tumour suppressor gene

Question 37

what does p53 do if DNA damaged

Answer 37

initiate DNA repair
arrest cell cyel
initiate apopsosis

Question 38

defective p53

Answer 38

allows abnormal cells to prliferation
unable to monitor DNA through cell divison
replication with damaged DNA

Question 39

apoptosis

Answer 39

programmed cell death

destroys cells that may be a threat

Question 40

apoptosis initiation

Answer 40

may be initiatied by withdraw of positive signals

or repeat of negative signals e.g. UV

Question 41

apoptosis

Answer 41

break down of nuclear envelope
blebbing
phagocytosis

Question 42

apoptosis vs necrosis

Answer 42

apop
- contrlled
energy dependatn
cells shrink
membrane in tact
non inflammatory 
no scarring 
nucelar fragmentation
physillogical
Necrosis
- uncontrlled
no ATP reqrueid
cellls swell
membrane not maintained
swelling 
scarring
large cell groups
nucelar dissolution
pathological

Question 43

what is apoptosis related by

Answer 43

intrinsic/extrinsic mehcanisms
many steps
bcl-2 inhibits the initiation of the intrinsic mechanism (cancer)

Question 44

caspases

Answer 44

proteolytic enzmes

Question 45

what do cascades present as

Answer 45

inactive proenzymes /zymogens

Question 46

apoptosis in disease

Answer 46

• Human papilloma virus inactivates p53
• Epstein barr virus protein similar to Bxcl- 2
• Melanoma inhibits expression of Apaf 1
• Fas antagonists – block T cell cytotoxicity
• Autoimmune eg SLE, Rheumatoid arthritis
• Increase in apoptosis eg HIV

Question 47

mitosis and apoptosis in dental physiology

Answer 47

• Craniofacial growth and development
• Homeostasis in mucosa, skin and pulp
• Tooth development
• Bone remodelling (eg in orthodontics)
• Wound healing (proliferation of keratinocytes to protect, apoptosis of immune cells )