L7 - Growth and Cancer

Question 1

What must occur before growth can occur

Answer 1

Patterning over a small scale

Question 2

How does differential growth account for differences in the limb in bats and humans

Answer 2

Have the same humerus - radius/ulna - digits

But in bats these are elongated to a much greater degree

Question 3

3 methods of growth

Answer 3

Cell proliferation
Cell enlargement
Accretion

Question 4

Cell proliferation AKA

Answer 4

Hyperplasia

Question 5

Cell enlargement AKA

Answer 5

Hypertrophy

Question 6

What drives G1 phase

Answer 6

Cdk4/6 and cyclin D

Question 7

What drives G1/S

Answer 7

Cdk2 and cyclin E

Question 8

What drives S/G2

Answer 8

Cdk2 and cyclin A

Question 9

What phase of the cell cycle do terminally differnetiated cells enter

Answer 9

Quiescent

Question 10

Early drosophila embryo is a

Answer 10

Synctiium (single multinucleate cell)

Question 11

Describe the cell cycle in the early divisions of the drosophila embryo

Answer 11

Rapid synchronous cycles of only S and M phases

Question 12

Describe what is seen at the 14th cycle

Answer 12

Slowing of the cycle and introduction of G2 phase

Question 13

What is the division rate in the drosophila embryo determined by

Answer 13

Location of that cell

Question 14

Groups of cells with similar fates may have similar division rates - what is term used to describe this

Answer 14

Mitotic domains

Question 15

Cell division in mitotic domains is controlled by what protein

Answer 15

String

Question 16

During the first 13 division describe the distribution of string

Answer 16

Uniformly distributed owing to its maternal origins

This allows for the rapid synchronous divisions

Question 17

Describe the distripution of string after the first 13 division

Answer 17

Zygotically expressed string produced under the direct control of the patterning genes

Question 18

What happens in the mesoderm to string and why?

Answer 18

Tribble blocks string

Mesoderm must first involute before any growth can occur

Question 19

Describe what would happen if there was an additional thymus gland - what ype of control is this

Answer 19

All organs maintain their size and multiple ammounts of tissue will be present
INTRINSIC CONTROL

Question 20

Describe what would happen if there was an additional spleen - what type of control is this

Answer 20

Both would grow to half the size such that the total ammount of spleen tissue remains the same

SYSTEMIC CONTROL

Question 21

What pathway controls the size of the cell

Answer 21

TOR pathway

Question 22

What pathway limits the size of organs

Answer 22

Hippo pathway

Question 23

Describe the hippo pathway when it is inactive

Answer 23

TF Yki/Yap/Taz is in the nucleus which stimulates growth and promotes the survival of cells

Question 24

Describe the hippo pathway when it is active

Answer 24

Transcritpion factor Yki/Yap/Taz excluded from the nucleus and growth is inhibited

Question 25

What factors lead to the activation of the hippo pathway What is the result of this activation

Answer 25

Cell cell contact Cell polarisation Activation of pathway leads to inhibition of grwoth

Question 26

What factors lead to the inactivation of the hippo pathway

Answer 26

Mechanical stress - because there are not enough cells so this causes some cells to become streched Other signalling pathways

Question 27

Describe a hippo mutant version of the fly imaginal disc

Answer 27

Mutant disc much bigger in size Yki is in the nucelus Ability to restrict growth has been lost

Question 28

Describe a hippo mutant liver

Answer 28

Mutant much bigger Yap/Taz in the nucleus Ability to restrict growth of cells has been lost

Question 29

Name an example of a area where growth rate is not unifrom

Answer 29

Head

Question 30

Why are pygmess shorter

Answer 30

Second growth spurt doesnt happen

Question 31

Size of the adult fly determined by

Answer 31

Size of the larva

Question 32

What affects duration and rate of fly larval growth

Answer 32

Insulin

Question 33

When the larva reaches a certain size what occurs

Answer 33

Metamorphosis

Question 34

What induces metamorphosis in the fly

Answer 34

Edcyson

Question 35

What are the main determinants in the difference in size of dogs

Answer 35

IGF and GH pathways

Question 36

What hormones control growth in mammals

Answer 36

GF1 GF2 IGF1 IGF2

Question 37

Production of growth hormone in the pituritry activated by

Answer 37

GHRH (growth hormone releasing hormone) | Somatostatin

Question 38

What is the main site for IGF production

Answer 38

Liver

Question 39

What an example of how maternal environment can affect growth

Answer 39

Shetland cross shire horse If mother is the Shetland then the foal is smaller

Question 40

Compare the signals used for development and then during post embryonic development

Answer 40

Dev - short range and small Post emb dev - influences from the environment act on the CNS which then produces hormones which act at the scale of the whole organism

Question 41

Molting is AKA

Answer 41

Ecdysis

Question 42

Why must motling occur

Answer 42

Since cuticle is rigid and doesnt allow for much growth to occur

Question 43

Intermolds are refereed to as

Answer 43

Instars

Question 44

Molting initiated by

Answer 44

Activtion of strech receptors in the cuticle

Question 45

Once strech receptors have been activated what occurs next

Answer 45

Release of protothoracicotrophic hormone from the corpus alatum

Question 46

Release of protothoracicotrophic hormone leads to _________________________ This leads to

Answer 46

Ecdyson from the prothoracic gland Molting then occurs under influecne of ecdyson

Question 47

Describe the process of molting

Answer 47

First cuticle separates from the epidermis While original cuticle is still present freed epidermal cells prolfierate and secrete a fluid forming a barrier which begins then secreting a new cuticle - only after this will the old cuticle be shead

Question 48

What prevents metomorphosis in flies

Answer 48

Ecydyson

Question 49

What causes ecdyson release - where is it released from

Answer 49

Brain releases prothoracicotrophic hormone which then acts on the prothoracic gland causes the release of ecdyson

Question 50

Describe how metamorphosis is triggered in frogs

Answer 50

Hypthalmus releases CRH acts of the pituitrary to release of TSH Causes the thyroid to release thyroxin (T3 T4)

Question 51

What delays metamorphosis in frogs

Answer 51

Prolactin

Question 52

Cancer is essentially the

Answer 52

Loss of growth control

Question 53

Where is cancer most common

Answer 53

In already proliferating cells - such as epithelia

Question 54

What are teratomas

Answer 54

Cancer cells which give rise to tissues of all 3 germ layers

Question 55

Protooncogenes

Answer 55

Once activated become oncogenes Genes that can cause cell division Ras Raf EGFR Myc

Question 56

Tumour supressior genes

Answer 56

Once inactive cause cancer Usually decrease the rate of cell division E.g. Rb, P53, ptc, APC, VHL

Question 57

Type of cancer caused by abberent Wnt

Answer 57

Colon cancer | Hepatocellular cancer

Question 58

Type of cancer caused by abberent Hh

Answer 58

BCC | Medulloblastoma

Question 59

Type of cancer caused by abberent Nodal

Answer 59

Melanoma

Question 60

Type of cancer caused by abberent Notch

Answer 60

Leukaemia

Question 61

Type of cancer caused by abberent EGF

Answer 61

Lung cancer | Breast cancer

Question 62

Describe dominantly inherited cancer syndromes

Answer 62

TSGS at the centre Two hit hypothesis If inherit a faulty copy of the gene Easier then for the remianing copy to become damaged