(3.3) Which is not a cue used to direct a growth cone.

Question

(3.3) Which is not a cue used to direct a growth cone.

BlackTom AI · Accepted Answer

Noggin antagonizes BMPs during neural induction and dorsal–ventral patterning of the embryo, and is not a classic guidance cue for steering growth cones.

Relevant knowledge points:
- A growth cone is the motile tip of a developing axon or dendrite that navigates the environment using guidance cues.
- Guidance cues fall into major classes: diffusible chemotropic factors (chemoattractants/chemorepellents such as netrins, Slits), contact-mediated cues (ephrins, semaphorins acting via membrane contact), extracellular-matrix cues (laminin, fibronectin, proteoglycans), cell adhesion molecules (CAMs, integrins), and neurotrophins (BDNF, NGF) that can influence directionality and survival.
- Noggin is a secreted protein that binds BMPs (bone morphogenetic proteins) preventing BMP receptor activation; its principal roles are neural induction and dorsal–ventral patterning in embryogenesis.

Step-by-step reasoning:
1. Identify what growth cones respond to: gradients of attractive/repulsive signals (e.g., netrin gradients attract commissural axons; Slit repels via Robo receptors; semaphorins often repel; ephrins mediate contact-dependent repulsion/attraction).
2. Compare noggin’s function: noggin binds BMPs and modulates tissue patterning early in development rather than creating spatial guidance gradients that directly steer growth cones.
3. Consider possible overlaps: BMP signaling can influence axon behavior in some contexts, but noggin’s canonical role is to block BMP-mediated dorsal/ventral specification; it is not categorized among the classical axon guidance molecules used by growth cones.
4. Conclude that noggin is not used to direct growth cones, whereas netrins, semaphorins, ephrins, Slits, CAMs, ECM molecules, and neurotrophins are.

Why the correct answer is correct:
Noggin’s molecular action and developmental role (BMP antagonism and neural induction) do not correspond to the mechanisms growth cones use to perceive directional cues. It does not function as an axon-attractant/repellent guidance cue in the standard lists taught in developmental neurobiology.

Why other typical options would be incorrect as "not cues":
- Netrins, semaphorins, Slits, ephrins, neurotrophins, CAMs and ECM molecules are all established growth-cone guidance cues (so they would be incorrect choices if the question asked “which is not a cue”).
Conclusion: Noggin cue is not a growth-cone guidance cue; this confirms the provided correct answer, "Noggin cue."

(3.3) Which is not a cue used to direct a growth cone.Single choice

Similar Questions

Upregulation of an EphA receptor in a nasal retinal ganglion axon that normally expresses low levels of this receptor would ______________.

Which guidance molecule/s is/are responsible for preventing commissural axons of the spinal cord from crossing the midline more than once during development?

Which of the following represent the CORRECT order of molecular steps involved in the movement of a growth cone towards a chemoattractive cue?

Which ONE of the following statements about axonal guidance is INCORRECT?

Guidepost cells release chemicals that

The implementation and loading phase of the Database Life Cycle (DBLC) involves _____.

Which of the following parameters is used to determine the concentration of protein in a spectrophotometer?

More Practical Tools for Students Powered by AI Study Helper

Homework AI Solver

Stylized AI Paper Writer

Plagiarism Checker Assistant

Citation AI Academic Writing Tool

In-Class Translation Assistant

AI Note Generator

AI Quiz Answers

Past Exam Questions from University Test Bank

Smart Practice Assistant

Adaptive Practice

Making Your Study Simpler