Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BMS247 - Stem cells > Post embryonic development > Flashcards

Post embryonic development Flashcards

1
Q

What does differential growth lead to?

A

Differences in SHAPE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the 3 ways that growth can occur?

A

1) Proliferation
2) Cell enlargement
3) Accretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is cell proliferation?

A

Cell divsion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How does cell enlargement cause growth?

Example?

A

Increase in cell size –> increase in organ size

Happens in cardiac hypertrophy (heart increase in size by increasing in cell size)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is accretion?

Example?

A

ECM being laid down outside of cells –> allowing them to grow

Bone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What drives the cells cycle?

How?

A

Cyclins and CDKs:

  • Different cyclins drive different parts of the cell cycle
  • Different cyclins activate different CDKs
  • CDKs control other proteins by PHOSPHORYLATING them
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How do different tissues grow in relation to each other?

A

They grow differently - all inherit their OWN individual growth programme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe the initial cell cycle of the drosophila

A
  • Nuclei initially go through initial rapid divisions (no G1 or G2 phases)
  • At cycle 14: cell cycle slows and G2 stage is inserted into the cycle
  • Nuclei move to the periphery of the embryo and become cellularised
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

As well as the insertion of G2 at cycle 14, what else happens in drosophila development?

A

Mitotic domains develop:

  • Each have their OWN cell cycle programme (divide differently)
  • But the cells within each domain behave in the SAME way
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How are mitotic domains in the drosophila controlled?

A

By STRING expression - which activates CDKs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What kind of protein is String?

A

A PHOSPHATASE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How is String expression controlled?

How?

A

By the patterning genes that set up the AP and DV axis of the embryo (gap,pair rule, segment polarity, D/V)

DIRECT LINK between the patterning genes and PROLIFERATION via STRING expression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What happens in the mesoderm in relation to string expression (exception)?

Why?

A

Expresses string EARLY but DOESN’T undergo cell division

Due to protein TRIBBLES - blocks string function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does the blockage of String by Tribbles allow?

A

The INVAGINATION of the mesoderm into the embryo, which must occur when the cell is dividing and not moving

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the experiments that try to determine how the organ knows how big to grow?

What are the results?

A

1) Graft limb bud from one species to another

  • -> INTRINSIC pattern of growth MAINTAINED
  • -> Limb develops that doesn’t fit the pattern of the rest of the body
  • -> INTRINSIC control

2) Transplant an additional thymus
- -> Retain their original size, more than original amounts of thymus tissue

3) Transplant additional SPLEEN
- -> Become HALF the NORMAL size (stop growing when there is a certain amount of total spleen tissue present)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What type of growth control controls the size of organs?

A

Intrinsic or extrinsic, depending on the organ

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is important in determining the size of specific structure?

A

The absolute dimensions, not the cell number

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What determines cell size?

How does this impact on the size of the animal?

A

Ploidy (the amount of copies of the genome that are present in the cell):

  • Cells in haploid are smaller than diploid which are smaller than triploid
  • BUT, the size of the animal will be the same
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What determines the size of the organ?

How?

A

MORPHOGENS

NOT growth factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the steepness of the morphogen gradient determined by?

A

The size of the organ

NOT the cell number

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the 2 pathways that impact on organ growth/size?

A

1) TOR pathway

2) Hippo pathway

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How does TOR impact on organ size?

A

Impacts on CELL SIZE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is an inhibitor of TOR?

What does this cause?

A

Rapomyosin

Causes cells to be SMALLER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What happens when the Hippo pathway is active/inactive?

A

When the pathway is INACTIVE:

  • The transcription factor is present in the NUCLEUS
  • -> Stimulates the growth and survival of cells

When the pathway the ACTIVE:
- The transcription factor is EXCLUDED from the nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What does the Hippo pathway control?

A

The organ size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the transcription factor of the Hippo pathway?

A

Yki - in drosophila

Yap/Taz in vertebrates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is the vertebrate analogue of Hippo?

A

Mst 1/2

28
Q

What do Hippo/Mst1/2 do?

A

Integrates various signals to create a ‘stop growing’ signal

29
Q

When is the Hippo pathway INactivated?

A

When not enough cells are around - cells are stretched –> mechanical stresses on the cell

  • TF in the nucleus, growth
30
Q

When is the Hippo pathway activated?

A

When there is lots of cell-cell contact

  • TF excluded from the nucleus, lack of growth
31
Q

What happens in a Hippo mutant?

What does this cause?

A

Loss of GROWTH RESTRICTION

  • -> Yki in the nucleus
  • -> overgrowth of the imaginal disc
32
Q

What happens when Mst1/Mst2 is mutant in the liver?

A

Tissue specific
Yap/Taz in the nucleus
–> Oversized liver

33
Q

What is size controlled by?

A

The RATE and DURATION of growth

34
Q

What is the the size of drosophila adult dependant on?

A

The size of the larva

35
Q

What affects the duration and rate of larval growth?

How?

A

Insulin signalling

Lots of insulin –> age quicker

36
Q

What occurs in insulin deficient flies?

A

Smaller cells
Fewer cells
Larva grow less
Flies are smaller

37
Q

What is IGF involved in?

A

AGING as well POST-EMBRYONIC growth

38
Q

What drives post-embyronic growth in mammals/humans?

A

Hormones:

  • IGF1
  • IGF2
  • GH
  • Maternal influence
39
Q

What drives the production of IGF driven by in mammals?

Where?

A

GH

Locally in LARGE amounts

40
Q

How does GH repress its own production?

A

1) Via inhibiting a growth hormone releasing hormone (GHRH)

2) By stimulating the production of SOMATOSTATIN - an inhibitor of GH

41
Q

What happens to IGF mutants in mice?

A

Mice are much smaller in size

42
Q

How does the maternal environment influence growth?

A

1) Size of the offspring is influenced by the size of the mother (but in the end, grow to be a similar size)
2) Mental conditions can affect the growth in the womb - has dramatic consequences later on

43
Q

What is low birth weight associated with?

A

CHD

44
Q

Where are the adult structures of the fly in the larva?

A

In the IMAGINAL DISCS

45
Q

What is the difference between signalling in embryogenesis and in post embryonic development?

A

Embryogenesis - short range signals

Post embryonic:

  • Long-range signals, more global
  • More input from the environment and the CNS –> resulting in the production of particular hormones that drive post embryonic growth
46
Q

What is Ecdysis?

A

Molting of the larva in between instars

47
Q

Why does Ecdysis happen?

A
  • Stretch receptors activated
  • Activation of PTTH
  • Drives the expression of ecdyson from the protothroratic gland
  • Drives the process of malting
48
Q

What is the final pupation of the drosophila controlled by?

How is tha

A

Ecdyson

49
Q

What happens during the final pupation/metamorphosis?

A

1) Environmental cues: light, temperature, feeding act on the brain - are integrated, which lead to the production of PPTH
2) PPTH acts on the protothoratic gland
3) Release of ECDYSON - lead to the final stages of metamorphosis

50
Q

What determines if the animal will undergo metamorphosis?

A

Ratio between Ecdyson (increased in response to environmental cues) and Juvenile hormone

51
Q

How does a tadpole turn into a frog?

A

1) Environmental cues (temperature, light, nutrition) act on the HYPOTHALAMUS
2) Release of corticotropin releasing hormone (CRH)
3) CRH acts to produce thyroid stimulating hormone (TSH)
4) TSH leads to the production of thyroxin (T4T3) –> leads to metamorphosis

52
Q

What feedback loop is thyroxin involved in?

A

POSITIVE feedback loop:

  • Certain amount of thyroxin will feedback on the production of CRH and TSH
  • To push the system forwards, REGARDLESS of a threshold of thytoxin
53
Q

What does prolactin do?

A

DELAYS metamorphosis

54
Q

What effects does metamorphosis have in different tissues?

A

Different effects:

  • Limb growth
  • Tail degeneration
55
Q

What causes cancer?

A

Loss of growth control

56
Q

Where is cancer most common?

Why?

A

In tissues that continue to divide throughout life
85% epithelia

These cells are ALREADY PROLIFERATIVE - one step closer to getting out of control proliferation (each cell division = chance of copying errors)

57
Q

What is a terotoma?

A

A tumour that looks like a disorganised embyro

58
Q

How are the cells in a terotoma thought to be transformed?

Why?

A

By epigenetics (not permanently)

Cells can be transformed from the teratoma and transplanted into a normal area where they would develop

59
Q

What are the PROTO ONCOGENES?

A

Ras
Raf
EGFR
Myc

60
Q

What are the TUMOUR SUPRESSOR genes?

A 
Rb 
p53
Ptc
APC
VHL
61
Q

How can developmental signals cause cancer?

A

Play a part in self-renewal (eg. wnt, hh)

62
Q

What cancer/s does activated Wnt cause?

A

Colon cancer

Hepatocellular cancer

63
Q

What cancer/s does activated Hh cause?

A

BCC

Medulloblastoma

64
Q

What cancer/s does activated Nodal cause?

A

Melanoma

65
Q

What cancer/s does activated Notch cause?

A

Leukemia

66
Q

What cancer/s does activated EGT cause?

A

Lung cancer

Breast cancer

BMS247 - Stem cells (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions