Test 3 - Development & Injury Repair

Question 1

Morphogen

Answer 1

secreted protein synthesized by signaling centers - diffusible signaling protein that can cause cells located at a different distance from the source to adopt different fates

Question 2

How do morphogens regulate neural development?

Answer 2

morphogens establish gradients

Question 3

Relationship between NUMB NOTCH DELTA

Answer 3

In drosophila sensory organ precursor (SOP) goes 2 ways:

1. NUMB- : no NUMB expression
2. NUMB+: numb inhibits NOTCH

Delta of neighboring cell activates NOTCH By proteolysis which allows Notch to enter cell and increase its expression which then repels Numb and cells grow apart.

Question 4

Where is Slit increased at the midline or laterally?

Answer 4

midline

Question 5

What happens if more total Robo proteins are expressed?

Answer 5

axon takes more lateral position

Question 6

4. Where are the cells that became post-mitotic latest going to be found in the cortex

Answer 6

top of the brain is latest in cell development (superficial)

Question 7

Why are the newest cells found superficially in the cortex?

Answer 7

radial glia -> post-mitotic neuron (intermediate) -> migrates towards cortical surface away from ventricle

in early development progenitors undergo symmetric division to expand pool and in later development division becomes asymmetric and progenitors are now radial glia

Question 8

What prevents tangling at the growth cone during actin polymerization?

Answer 8

homophilic binding of DSCAM proteins

Question 9

What is the axon growth cone made up of?

Answer 9

Actin? filopodium and lamillipodium