Multicellularity 2 Flashcards
1
Q
what are radial symetrical animals?
A
1 axis of asymmetry
2
Q
what receptors do WNT bind to?
A
frizzled receptors
3
Q
What is the Wnt signalling pathway in the absence of Wnt?
A
- frizzled is unbound
- GSK3beta phosphorylates beta-catenin
- beta-catenin is degraded
- TCF is inactive
- Wnt-responsive genes are off
4
Q
What is the Wnt signalling pathway in the presence of Wnt?
A
- GSK3beta is bound to the receptor
- beta-catenin is stable and goes to the nucleus
- it binds TCF
- Wnt genes turned on
5
Q
What is non-canonical Wnt signalling
A
- cell adhesion/cell movement
- cytoskeletal rearrangement
6
Q
Do choanoflagellates have the Wnt pathway?
A
No
7
Q
What are the radiata?
A
- Cnidaria
- Placozoa
- Ctenphora
- Porifera
8
Q
Where is Wnt expressed in bilateral organisms?
A
posterior end
9
Q
Where are Wnt inhibitors expressed in bilateral organisms?
A
Anterior end
10
Q
How did nerves evolve between sponges and Ctenophora?
A
theorised that flask cells evolved into nerve cells
11
Q
What is the role of flask cells in sponges?
A
- may be a precursor to nerves
- contain a junction similar to a synapse
- sponge contain synaptic genes in the flask cells
