Brainscape's Knowledge GenomeTM

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


See full index

BMS242 Developmental Biology > L8 - Germ Layer Induction and Gastrulation > Flashcards

L8 - Germ Layer Induction and Gastrulation Flashcards

1
Q

What is cell differnetiation

A

Process by which cells become different from each other and are able to acquire specialised properties

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

What is cell dif governed by

A

Changes in gene expression which dictate the repertoire of proteins synthesised

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

Describe extrinsic control

A

Cell non autonomous

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

Describe intrinsic control

A

Cell autonomous

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

Example of intrinsic control

A

Transcription factors

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

Example of extrinsic control

A

Morphogens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does the ectoderm give rise to

A

Skin
Nervous system
Pigmented cells

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

What does the mesoderm give rise to

A

Muscle
Kidney
Blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What does the endoderm give rise to

A

Lung
Thyroid
Pancreas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What layer gives rise to the sperm and egg

A

The germ layer

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

Gastrulation is best kniw through studies in ____

A

Xenopus

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

What occurs at the four cell stage

What does this give rise to

What are these two known as

A

Horizontal clevage

4 cells on the top, 4 cells on the bottom

Animal and vegetal cells

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

What are animal cells known as in chicks and human

A

Epiblast

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

What are vegetal cells known as in chicks and humans

A

Hypoblast

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

What is given rise to after the four cell horizontal cleavage

A

Morula

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

What is the morula

A

Hollow sphere of many cells which has a clear define animal and vegetal hemisphere

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

Where is the polarity in the oocyte seen

Why is this the case

A

Even before fertilisation

Due to gravity causing different cytoplasmic determinantns to sink to one part of the egg

Leads to the formation of the animal and vegetal pole

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

What is turned on in the cells in the vegetal pole

A

TFs come to be turned on in the vegetal pole - example of hich is Vgt

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is VgT

A

Vegetal- T-boc

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

Where is VgT localised to

A

Localised to the nucelus in the vegetal hemisphere cells

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

What does VgT bind to

What is the result of this

A

The promoter of nodal

Causes activation of Nodal

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

What is Nodal

Where does it act

How does it act

A

Secreted morphogen that can diffuse out of the vegetal cells into animal hemisphere

Acts on the cells in animal hemisphere were there are receptors

Activates the nodal signal trnasduction pathway

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

What is the effect of cells that recieve high nodal

A

Endoderm

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

What is the effect of cells that recicve intermediate nodal

A

Mesoderm

25
Q

What is the effect of no nodal

A

Ectoderm

26
Q

Where is the Wnt pathway activated

A

On the dorsal side of the embryo

27
Q

What does the point of Wnt activation mark for the future

A

Marks the future posterior dorsal part of the body

28
Q

Where does sperm always fertilise the egg

A

Sperm always the animal side of the egg

29
Q

What happens where the Wnt pathway is activated

A

Movements of gastrulaion begin

30
Q

What forms directly opposite the point where the sperm enters

A

Organiser forms

This is brought about by the fact that when the sperm enters the egg it initiates the rotation of the cortex

31
Q

How many sides is the Wnt pathway activated

A

JUST the one side of the cell

32
Q

What is the crucial TF involved wwith canonical Wnt signalling

A

B-catenin

33
Q

What is the effeect of active Wnt singalling on B-catenin

A

Stabilises - allowing the entry of B-catenin to enter the nucleus and gene expression to be changed

34
Q

What is the effect of B-catenin on Nodal

A

Increases levels of Nodal

So transforms Nodal into a gradient

35
Q

What is the region of overlap of Nodal and active Wnt

A

Nieuwkoop centre

36
Q

Once Nodal has been transformed to a gradient what is it acting as

A

Morphogen

37
Q

What occurs at the dorsal where Nodal is high

A

Forms the organiser

38
Q

What forms at the ventral end where Nodal is low

A

Ventral mesoderm froms

39
Q

Why is Nodal high at the dorsal end

A

Interaction of B-catenin (from active Wnt signalling) and VgT - gives high Wnt

40
Q

Why is Nodal low at the ventral end

A

Only Vgt

41
Q

The organiser forms under what conditions

A

Where cells recieve very high nodal and Wnt

42
Q

What is the main gene expressed at the organiser

A

Gsc

43
Q

Decribe the upstream enhancers of Gsc

A

Proximal element - Wnt/B catenin

Distal element - TGF-B/Nodal

44
Q

Describe the conditions for when Gsc is produced

A

BOTH proximal and distal elements must be activate by Wn/B-catenin and TGf-B/Nodal

45
Q

What do cells of the organiser differentiate into

A

Axial mesoderms

46
Q

Describe the migration of axial mesoderm

A

Migrate collectively in a process called convergent extension

47
Q

Why are different types of axial mesoderm cells produced

A

Siamois and Gsc are expressed at fractionally different leveles

48
Q

Gastrulation is driven by movement of cells from __________ to _________

A

Posterior to anterior

49
Q

What does the organiser undergo

A

Self differentiation

50
Q

What does the organsier give rise to

A

Mix of progenitor cells

Prechordal mesendoderm
Prechordal mesoderm
Notochord
Together forming the axial mesoderm

51
Q

What are the three main cell type of precurrsor form in the organiser region

A

Pharyngeal (anterior) endoderm
Prechordal mesoderm
Notochord

52
Q

What is the shape of the involuting axial mesoderm

A

Rod shape

53
Q

What does the axial mesoderm move over

A

Blastocoel

54
Q

As the preaxial mesoderm moves what does it form

A

Fibronectin rich pathwya which binds to inegrins

55
Q

Integrins are expressed on the

A

Organiser cells

56
Q

The pahryngeal endoderm and the prechordal mesoderm mark the

A

Furture anterior part of the embryo

57
Q

What are the last cells to migrate

A

The notochord cells

58
Q

What do the notochord cells form

A

The future posterior part of the embryo

59
Q

Explain how the blastocoel forms

A

At some point there is a change in osmolarity

Results in an influx of water so morulla changes to a hollow sphere with a central fluid filled blastocoel

BMS242 Developmental Biology (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions