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 pumps three sodium ions out of the cell and two potassium ions into the cell using ATP, creating an electrochemical gradient.

Question 2

A red blood cell is placed in a solution and swells until it bursts. Which of the following best describes the tonicity of the solution relative to the cell, and the direction of water movement?

Accepted Answer

The solution is hypotonic; water moves into the cell.

Question 3

Which of the following molecules is most likely to diffuse directly through the lipid bilayer of a plasma membrane without the aid of a transport protein?

Accepted Answer

Oxygen ($$\mathrm{O_2$})$$

Question 4

Which of the following best explains why steroid hormones can pass through the plasma membrane while peptide hormones cannot?

Accepted Answer

Steroid hormones are lipid-soluble and can diffuse through the hydrophobic core of the membrane.

Question 5

A patient is given a drug that blocks voltage-gated sodium channels in neurons. What effect will this have on the generation of action potentials?

Accepted Answer

Action potentials will not be generated because depolarization cannot occur.

Question 6

Which of the following best describes the role of second messengers such as cyclic AMP ($$\mathrm{cAMP}) in $$cell signaling?

Accepted Answer

They amplify the signal from a membrane receptor to target molecules inside the cell.

Question 7

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

Accepted Answer

Elevated blood glucose stimulates insulin release, which lowers blood glucose and inhibits further insulin secretion.

Question 8

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

Accepted Answer

Paracrine signaling is local, affecting nearby cells, while endocrine signaling involves hormones traveling long distances via the bloodstream.

Question 9

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

Accepted Answer

The neuron integrates all inputs at the axon hillock, and fires an action potential if the membrane potential reaches threshold.

Question 10

Which of the following best explains the function of Schwann cells?

Accepted Answer

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

Question 11

Which of the following scenarios best illustrates the concept of cotransport across a cell membrane?

Accepted Answer

A glucose molecule is transported into the cell against its concentration gradient, coupled with sodium moving down its gradient.

Question 12

Which of the following best describes the role of ligand-gated ion channels in nerve signal conduction?

Accepted Answer

They open when a specific chemical (ligand) binds, allowing ions to flow and generate graded potentials.

Question 13

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

Accepted Answer

Reception → Transduction → Response

Question 14

A person is exposed to a loud sound. Which of the following best describes how the intensity of this sensory stimulus is encoded by the nervous system?

Accepted Answer

By increasing the frequency of action potentials generated by the sensory neuron.

Question 15

Which of the following best describes the difference between exocytosis and endocytosis?

Accepted Answer

Exocytosis releases substances from the cell by vesicle fusion with the plasma membrane, while endocytosis brings substances into the cell by forming vesicles from the plasma membrane.

Question 16

Which of the following best explains why the fluid-mosaic model is an appropriate description of the plasma membrane?

Accepted Answer

The membrane is composed of a phospholipid bilayer with proteins and other molecules that can move laterally, creating a dynamic and flexible structure.

Question 17

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

Accepted Answer

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

Question 18

Which of the following is an example of antagonistic hormones and their role in homeostasis?

Accepted Answer

Insulin and glucagon regulate blood glucose levels in opposite directions.

Question 19

Which of the following best describes the function of the sympathetic division of the autonomic nervous system?

Accepted Answer

It prepares the body for 'fight or flight' responses, such as increasing heart rate and dilating pupils.

Question 20

Which of the following best explains how a cascade in signal transduction can amplify a cellular response?

Accepted Answer

Each step in the cascade activates multiple molecules at the next step, resulting in a large number of activated molecules from a single signal.

Bio 103 Exam 2 Study Guide: Membranes, Cell Communication, Endocrine System, Neurons, Nervous System, and Senses

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