Question 1

Which of the following best describes the function of the sodium-potassium pump in maintaining the resting membrane potential of a neuron?

Accepted Answer

It actively transports 3 Na\^+ ions out of the cell and 2 K\^+ ions into the cell, using ATP, creating an electrochemical gradient.

Question 2

A cell is placed in a hypertonic solution. What will happen to the cell, and why?

Accepted Answer

Water will move out of the cell, causing it to shrink, because the solute concentration is higher outside the cell.

Question 3

Which equation correctly represents the calculation of osmotic pressure ($$\Pi) $$according to van't Hoff's law?

Accepted Answer

$$\Pi = iCRT$$

Question 4

Which of the following is a correct example of negative feedback in the endocrine system?

Accepted Answer

High blood glucose stimulates insulin release, which lowers blood glucose, reducing further insulin secretion.

Question 5

Which statement best explains why the same signaling molecule can produce different responses in different cell types?

Accepted Answer

Different cells have different receptors or intracellular signaling pathways for the same molecule.

Question 6

Which of the following best describes the role of voltage-gated ion channels in the generation of an action potential?

Accepted Answer

They open in response to changes in membrane potential, allowing Na\^+ influx and K\^+ efflux, which propagates the action potential.

Question 7

Which of the following is NOT a function of membrane proteins?

Accepted Answer

Synthesizing DNA for cell division.

Question 8

Which process describes the movement of water across a semipermeable membrane from an area of low solute concentration to high solute concentration?

Accepted Answer

Osmosis

Question 9

A neuron receives both excitatory and inhibitory signals. Which of the following best describes how it decides whether to fire an action potential?

Accepted Answer

It fires an action potential if the sum of all signals reaches the threshold at the axon hillock.

Question 10

Which of the following best describes the difference between paracrine, synaptic, and endocrine signaling?

Accepted Answer

Paracrine signaling acts locally between nearby cells; synaptic signaling uses neurotransmitters across synapses; endocrine signaling involves hormones traveling through the bloodstream to distant targets.

Question 11

Which of the following best describes the function of Schwann cells in the nervous system?

Accepted Answer

They form myelin sheaths around axons in the peripheral nervous system, increasing the speed of nerve impulse conduction.

Question 12

Which of the following is a correct sequence of events in cell signaling?

Accepted Answer

Reception $$\rightarrow$$ Transduction $$\rightarrow$$ Response

Question 13

Which of the following is a second messenger commonly involved in signal transduction cascades?

Accepted Answer

cAMP (cyclic adenosine monophosphate)

Question 14

Which of the following best explains the difference between facilitated diffusion and active transport?

Accepted Answer

Facilitated diffusion moves molecules down their concentration gradient via transport proteins without energy; active transport moves molecules against their gradient using energy (usually ATP).

Question 15

Which of the following is true about tropic hormones?

Accepted Answer

They stimulate other endocrine glands to release hormones.

Question 16

Which of the following best describes the role of the axon hillock in a neuron?

Accepted Answer

It is the region where the summation of signals determines if an action potential will be initiated.

Question 17

Which of the following best describes the process of exocytosis?

Accepted Answer

The cell releases substances to the extracellular environment by fusing vesicles with the plasma membrane.

Question 18

Which of the following best explains how G protein-coupled receptors (GPCRs) initiate a cellular response?

Accepted Answer

GPCRs activate G proteins, which then trigger production of second messengers such as cAMP, leading to a cellular response.

Question 19

Which of the following is a correct description of the role of astrocytes in the nervous system?

Accepted Answer

They provide structural and metabolic support for neurons and help maintain the blood-brain barrier.

General Biology: Membrane Proteins, Cell Signaling, Endocrine System, Nervous System, and Senses

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