Exam 2: Signaling Within Neurons

In transportation within neurons, which direction is retrograde? Which direction is anterograde?

Why does the Na⁺ conductance decrease after a short time?

Which membrane proteins require ATP to move ions across the membrane? Choose all that apply.

What does 'local protein translation' mean in neurons?

What kinds of organelles have been localized to dendrites?

How do Na⁺ and K⁺ ion channel structures allow them to detect changes in voltage across the membrane? Note: Questions 2-42 and 2-43 refer to the data in Figure Q2-42. These questions may be used independently or as a group.

Why are action potentials usually generated at the axon hillock in vertebrate neurons?

In order to understand how currents move during an axon potential Hodgkin and Huxley used the voltage clamp technique. Why was this technique so important? Choose all that apply.

In the cochlea of the ear sounds waves are turned into electrical signals through special cells called hair cells. When a wave travels through the cochlea it moves the 'hairs' and opens ion channels that are permeable to K⁺ and Ca²⁺. These 'hairs' are in a fluid that has a very high K⁺ concentration compared to the inside of the cell. A. When the ion channels open, in what direction do K⁺ ions flow and why? B. Based on this relative concentration difference of K⁺, what do you predict the equilibrium potential for K⁺ will be: positive, negative or zero?

What helps maintain the ion concentration across the membrane of neurons?

If myelin makes action conduction velocity faster, why are axons not completely covered with myelin? That is, what would happen to the electrical signal if the axon was completely covered in myelin and had no Nodes of Ranvier?

Which membrane proteins use the electrochemical gradient to move ions across the membrane? Choose all that apply.

For each labeled point (A-D) on the action potential shown in Figure Q2-34, state whether the conductance through voltage-dependent Na⁺ and K⁺ channels is low, high, or no conductance. Explain. [Note: For this answer, ignore conductance through leak channels.] Figure Q2-34

In Figure Q2-42, amino acids 6-46 were removed from the ShB channel through mutagenesis. A. What happened to the single channel response? B. When the ShB peptide (the first 20 amino acids of the ShB protein) was added to the ShBΔ6-46 protein, what happened to the single channel response and what does that tell you about the function of the first 20 amino acids?

What is the function of exocytosis? Choose all that are correct.

Proteins that function in the cytoplasm and nucleus are synthesized in/on which organelle?

What is the 'driving force'?

The equilibrium potential for any ion is the point at which two forces/gradients balance each other. What are the two forces/gradients?

The brains of patients with Alzheimer's disease show degradation of microtubule function, in part from over-phosphorylation of the microtubule-associated protein, tau. What might happen to neurons when microtubule function is disrupted?