Neurite Outgrowth and Axon Guidance Factors

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What was the purpose of the experiment described in the text?

To investigate the impact of light on retinal axon development

To analyze the migration patterns of ganglion cells

To study how cues guide the formation of the optic tract (correct)

To determine the number of axons present in the optic chiasm

What happened to the direction of axon growth when grafts were rotated 90 degrees counterclockwise?

Axons changed their growth direction entirely

Axons grew away from the original position

Axons grew toward their original position (correct)

Axons grew in a random pattern

What was the role of Ganglion Cells in the experiment?

To label retinal axons before reaching the optic chiasm

To study the embryonic optic tract

To observe axon growth patterns at the chiasm

To make decisions at the optic chiasm (correct)

What did the experiment aim to visualize using microscopy?

Axon guidance at the optic chiasm (C) Signup and view all the answers

How did retinal axons behave after crossing the optic chiasm?

They formed optic tracts (B) Signup and view all the answers

What was significant about the decisions made by Ganglion Cells at the optic chiasm?

They demonstrated divergent choices (D) Signup and view all the answers

What is the main responsibility of the growth cone at the end of an axon?

Dictate the direction and destination of the axon (C) Signup and view all the answers

What are filopodia and lamellipodia in the growth cone mainly composed of?

Actin (B) Signup and view all the answers

What happens when cytochalasins inhibit actin polymerization in the growth cone?

Growth cone retraction (D) Signup and view all the answers

Which structure within the growth cone guides pioneer microtubules along and helps traverse through the F-actin network?

F-actin arcs (B) Signup and view all the answers

What is a key role of receptors on the growth cone?

Sense environmental cues (D) Signup and view all the answers

In which domain of the growth cone are microtubules hindered by F-actin arcs acting as barriers?

Transition (C) Signup and view all the answers

What is the effect of microtubule stabilizers placed on a specific side of the growth cone?

Cause growth cone turning towards that axis (A) Signup and view all the answers

How does Cytochalasin B affect actin filaments in the growth cone?

Causes actin filaments to retreat towards the central region (D) Signup and view all the answers

What is the role of adhesions between the growth cone and extracellular matrix (ECM)?

Facilitate traction and growth cone movement (A) Signup and view all the answers

What is the consequence of a loss of F-actin from the periphery of the growth cone?

Complete collapse and retraction of the growth cone (C) Signup and view all the answers

How do retrograde flow of actin and microtubule interactions influence other structures in the growth cone?

Pull other structures back with them (B) Signup and view all the answers

What is the function of chemoattraction in growth cone propulsion?

Direct axon using soluble molecules (C) Signup and view all the answers

Which molecules are major components of basal laminae and promote axon outgrowth?

Laminins (B) Signup and view all the answers

In the experiment involving cell adhesion assay to identify NCAMs, which type of cell adhesion molecules are examples of calcium-independent adhesion?

NCAM (B) Signup and view all the answers

What happens when Ephrin binds to Eph receptors?

It mediates an inhibitory signal guiding axons (D) Signup and view all the answers

Which class of Ephrins has a GPI anchor?

Ephrin A (D) Signup and view all the answers

What is the function of Ephrin Bs in the optic tectum?

Attract axons from ventral RGCs (A) Signup and view all the answers

How do integrins interact with the extracellular matrix?

By binding to laminins and other matrix molecules (B) Signup and view all the answers

Which type of signaling occurs through Ephrin A5?

Forward repulsive (C) Signup and view all the answers

What type of proteins are Ephrin As?

GPI anchored (A) Signup and view all the answers

Which molecule is responsible for the attraction of axons to the floor plate in commissural neurons?

Netrin (B) Signup and view all the answers

Which factor prevents RGC axons from wandering outside of the optic nerve according to the text?

Sema5A (B) Signup and view all the answers

Which receptors are required for attraction in the context of Netrins according to the text?

DCC and UNC5 (A) Signup and view all the answers

What is responsible for repulsion in axons that grow away from the midline according to the text?

UNC-40 receptor (A) Signup and view all the answers

Which GTPase promotes growth cone collapse?

RhoGTP (B) Signup and view all the answers

What is the function of GAPs in the GTPase cycle?

Accelerate the inactivation of GTPases (A) Signup and view all the answers

Which netrin receptor complex induces growth cone attraction?

Binding of netrin to DCC homodimers (D) Signup and view all the answers

What is the role of Ephexin in intracellular signaling?

Activation of RhoGTP (D) Signup and view all the answers

What mechanism leads to Slit-induced repulsive migration?

Reduction of Cdc42 activity by Slit-induced Robo activation (B) Signup and view all the answers