Q: Which equation is used to calculate the equilibrium potential for a single ion, such as potassium, across a membrane?

The Nernst equation: $$E = \frac{61}{z} \log \left( \frac{[\text{ion}]_{\text{out}}}{[\text{ion}]_{\text{in}}} \right)$$

Question 1

Which of the following best describes the function of the integrator (integrating center) in a reflex pathway?

Accepted Answer

It receives input signals, compares them to a set point, and determines the appropriate output signal.

Question 2

A scientist hypothesizes that cold temperatures cause birds to eat more food. In an experiment, birds are kept at 27°C, 4°C, 0°C, and -12°C, and their food intake is measured. What is the independent variable in this experiment?

Accepted Answer

The temperature at which the birds are kept

Question 3

If a cell is placed in a solution and swells, which of the following best describes the tonicity of the solution relative to the cell?

Accepted Answer

The solution is hypotonic to the cell.

Question 4

Which of the following is a key difference between simple diffusion and facilitated diffusion across a cell membrane?

Accepted Answer

Facilitated diffusion uses membrane proteins to transport specific molecules, while simple diffusion does not.

Question 5

A cell is placed in a solution with a higher concentration of non-penetrating solutes than inside the cell. What will happen to the cell and why?

Accepted Answer

The cell will shrink because water moves out of the cell.

Question 6

Which equation is used to calculate the equilibrium potential for a single ion, such as potassium, across a membrane?

Accepted Answer

The Nernst equation: $$E = \frac{61}{z} \log \left( \frac{[	ext{ion}]_{	ext{out}}}{[	ext{ion}]_{	ext{in}}} ight)$$

Question 7

Which of the following best describes the role of the Na⁺/K⁺-ATPase pump in maintaining cell homeostasis?

Accepted Answer

It uses ATP to actively transport Na⁺ out of the cell and K⁺ into the cell, maintaining their gradients.

Question 8

Which of the following is an example of secondary active transport?

Accepted Answer

The sodium-glucose linked transporter (SGLT) using the Na⁺ gradient to move glucose into the cell

Question 9

Which of the following best explains why the lumen of the digestive tract is considered part of the external environment?

Accepted Answer

Substances in the lumen have not yet crossed a cell membrane to enter the body's internal environment.

Question 10

Which type of cell junction allows direct cytoplasmic communication between adjacent cells?

Accepted Answer

Gap junctions

Question 11

A patient is given a drug that blocks the action of a specific receptor. This drug is acting as a(n):

Accepted Answer

Antagonist

Question 12

Which of the following best describes the function of the extracellular matrix (ECM) in tissues?

Accepted Answer

It provides structural support and helps cells bind together.

Question 13

Which of the following is a correct example of a functional antagonist in hormone action?

Accepted Answer

Insulin and glucagon regulating blood glucose levels

Question 14

Which tissue type is primarily responsible for internal communication within the body?

Accepted Answer

Nervous tissue

Question 15

Which of the following best describes the process of signal amplification in a signal transduction pathway?

Accepted Answer

A single signal molecule triggers a cascade, resulting in a large cellular response.

Question 16

Which of the following is a characteristic of peptide hormones?

Accepted Answer

They are composed of multiple amino acids and are often stored in vesicles.

Question 17

A researcher is studying the rate of diffusion of a solute across a membrane. According to Fick's Law, which of the following changes would increase the rate of diffusion ($$J$$)?

Accepted Answer

Increasing the concentration gradient across the membrane

Question 18

Which of the following best explains why facilitated diffusion exhibits saturation kinetics, while simple diffusion does not?

Accepted Answer

Facilitated diffusion relies on a finite number of transport proteins, which can become saturated.

Question 19

Which of the following best describes the role of calcium ions ($$Ca^{2+}) in $$neurotransmitter release at a synapse?

Accepted Answer

$$Ca^{2+}$$ enters the presynaptic neuron and triggers exocytosis of synaptic vesicles.

Question 20

A patient has a genetic defect that prevents the formation of tight junctions in epithelial tissue. Which of the following is a likely consequence?

Accepted Answer

Increased leakage of substances between cells

Anatomy & Physiology Exam 1 Review: Homeostasis, Physiology, Cell Structure, and Membrane Transport

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