Question 1

Which glial cell type is primarily responsible for myelination in the central nervous system (CNS)?

Accepted Answer

Oligodendrocytes

Question 2

During the generation of an action potential, which ion channel opens first to initiate depolarization?

Accepted Answer

Na$$^+$$ channels

Question 3

Which equation is used to calculate the resting membrane potential of a neuron, considering multiple ions?

Accepted Answer

Goldman equation: $$V_m = \frac{RT}{F} \ln \left( \frac{P_{K^+}[K^+]_{out} + P_{Na^+}[Na^+]_{out} + P_{Cl^-}[Cl^-]_{in}}{P_{K^+}[K^+]_{in} + P_{Na^+}[Na^+]_{in} + P_{Cl^-}[Cl^-]_{out}} \right)$$

Question 4

A mutation disrupts the function of the axon hillock in a neuron. Which process would be most directly affected?

Accepted Answer

Integration of incoming signals and initiation of action potentials

Question 5

Which neurotransmitter is typically excitatory at chemical synapses in the central nervous system?

Accepted Answer

Acetylcholine

Question 6

Which type of cell signaling involves hormones traveling long distances through the bloodstream to reach target cells?

Accepted Answer

Endocrine signaling

Question 7

A drug blocks ligand-gated ion channels at a synapse. What is the most immediate effect on neuronal communication?

Accepted Answer

Prevention of rapid postsynaptic depolarization

Question 8

Which second messenger is directly activated by adenylyl cyclase and subsequently activates protein kinase A (PKA)?

Accepted Answer

cAMP

Question 9

Which feedback loop mechanism amplifies a biological signal, such as during the generation of an action potential?

Accepted Answer

Positive feedback

Question 10

Which cytoskeletal filament type is primarily responsible for maintaining cell shape and enabling cell motility?

Accepted Answer

Microfilaments (actin)

Question 11

A patient has a genetic defect in dynein. Which cellular process is most likely to be impaired?

Accepted Answer

Retrograde transport along microtubules

Question 12

Which protein regulates actin polymerization by promoting growth at the plus end of microfilaments?

Accepted Answer

Profilin

Question 13

Which cytoskeletal structure is characterized by a 9+2 arrangement and is essential for ciliary and flagellar movement?

Accepted Answer

Axoneme

Question 14

A researcher treats cells with colchicine, a drug that destabilizes microtubules. Which cellular process would be most affected?

Accepted Answer

Organelle transport and mitotic spindle formation

Question 15

Which motor protein moves vesicles toward the plus end of microtubules, away from the cell center?

Accepted Answer

Kinesin

Question 16

Which cytoskeletal filament type lacks polarity and is mainly involved in providing mechanical strength and anchoring organelles?

Accepted Answer

Intermediate filaments

Question 17

Which process is directly powered by ATP hydrolysis in muscle cells?

Accepted Answer

Sliding of actin and myosin filaments in sarcomeres

Question 18

Which signaling pathway involves a receptor with intrinsic tyrosine kinase activity that autophosphorylates upon ligand binding?

Accepted Answer

RTK pathway

Question 19

A mutation in the ARP2/3 complex would most directly affect which cellular process?

Accepted Answer

Branched actin filament formation

Question 20

Which of the following best describes the role of astrocytes in the nervous system?

Accepted Answer

Support, regulation of the blood-brain barrier, and neurotransmitter regulation

Cell Biology Study Notes: Nervous System, Cell Signaling, and Cytoskeletal Systems

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