Plasma membrane ll

Front

Which of the following describes the role of the sodium-potassium pump (Na⁺/K⁺-ATPase) in cellular homeostasis?

Back

It actively transports Na⁺ out of the cell and K⁺ into the cell.

Front

How does the lipid solubility of a solute impact its ability to cross the plasma membrane?

Back

Solutes that are lipid-soluble can easily diffuse across the membrane without the need for transport proteins.

Front

Which of the following statements best explains the role of electrical charge in solute movement across the plasma membrane?

Back

Solutes with a neutral charge pass more easily through the lipid bilayer than charged solutes.

Front

Which condition would most likely enhance the movement of a solute across the plasma membrane via passive diffusion?

Back

A high lipid solubility of the solute

Front

Which of the following statements about ΔG for membrane-soluble molecules is correct?

Back

ΔG for membrane transport can be positive, negative, or zero depending on the concentration gradient and electrical potential

Front

The ΔG for transport of a molecule across a membrane is zero under which of the following conditions?

Back

The concentrations of the molecule are the same on both sides of the membrane, and the membrane potential is zero.

Front

If the free energy change (ΔG) of a solute transport is calculated to be +3.45 kJ/mol, what does this imply about the transport process?

Back

The transport is non-spontaneous and requires energy input.

Front

When a solute moves across a membrane against its concentration gradient, the calculated free energy change (ΔG) is found to be +12.2 kJ/mol. Which of the following statements is true?

Back

Active transport mechanisms are likely involved.

Front

Given a monovalent electrolyte (e.g., NaCl) with a concentration gradient where the intracellular concentration is 10 mM and the extracellular concentration is 150 mM,

calculate the change in free energy (ΔG) for the diffusion of the electrolyte across the plasma membrane at 37°C. Assume

R=1.987 cal/(mol*K)

Back

-1669.18 kcal/mol

Front

What role do ion channels play in facilitated diffusion?

Back

They allow specific ions to pass through the membrane according to their concentration gradient.