Which of the following statements best describes the selective permeability of the cell membrane?

Which of the following best describes the permeability of the cell wall?

The model below depicts the movement of several ions across a cell membrane. For each ion, the relative concentration on each side of the membrane is shown.

Which of the following statements accurately describes one of the movements shown in the model?

The model below depicts the movement of several ions and molecules across a cell membrane. For each ion or molecule, the relative concentration on each side of the membrane is shown.

Which of the following statements accurately describes one of the movements shown in the model?

If ATP hydrolysis is inhibited, which of the following types of movement across a cell membrane would likely also be inhibited?

The movement of ions across a cell membrane can generate a membrane potential, or a voltage difference, across the membrane.

In neurons, this occurs when sodium-potassium pumps, Na+ / K+, ATPases, transport sodium ions (Na+) and potassium ions (K+) across the cell membrane against their concentration gradients. The action of these pumps, combined with the diffusion of certain ions through protein channels in the membrane, results in a resting membrane potential of approximately −70mV with respect to the inside of the cell.

Which of the following diagrams best represents the resting membrane potential of a neuron?

An action potential occurs when a neuron sends an electrical signal down its axon. When at rest, the neuron’s plasma membrane helps maintain a concentration gradient of sodium ions (Na+) between the neuron’s cytoplasm and the extracellular fluid. During an action potential, Na+ moves down this gradient, passing from the extracellular space into the cytoplasm of the neuron.

Which of the following is the most likely mechanism by which Na+ moves across the plasma membrane of a neuron during an action potential?

The model below shows how glucose, sodium ions (Na+), and potassium ions (K+) move between the intestinal lumen, an epithelial cell, and the blood in the small intestine. The relative concentrations of glucose, Na+, and

K+ inside and outside the epithelial cell are indicated.

Based on the model, which of the following movements does not require an input of energy?

Which of the following is true about the transportation of substances across the lipid region of the cell membrane?

A group of biology students weighed several potato cubes and placed them in open beakers containing various sucrose solutions at 45∘C. The following day, the students weighed the potato cubes again and calculated the differences in mass.It was determined that solute potential equilibrium was reached at 0.50M.

Solute potential of a solution: ψs​= − iCRT

i = ionization constant (1.0 for sucrose)

C = molar concentration

R = pressure constant (0.0831L⋅bar⋅mol⁻¹⋅K^{−10 )}

T = temperature in Kelvin (C + 273)

What is the solute potential of the potato cubes?

A student places a zucchini cube into an open container containing a 0.20M sucrose solution. The temperature of the solution is kept steady at 27∘C.

Water potential: ψ=ψp​+ψs

​

ψp​= pressure potential

ψs​= solute potential

Solute potential of a solution: ψs​= − iCRT

i = ionization constant (1.0 for sucrose)

C = molar concentration

R = pressure constant (0.0831L⋅bar⋅mol⁻¹⋅K^{−10 )}

T = temperature in Kelvin (C + 273)

What is the water potential of the zucchini cube?

The solute potential of a plant cell is −12 bar, and its pressure potential is 3 bar. The plant cell is placed into a solution with a water potential of −10 bar.

Water potential: ψ=ψp​+ψs

​

ψp​= pressure potential

ψs​= solute potential

What is the water potential of the cell, and in which way will water move?

A student places a potato cube into a beaker of distilled water as shown below.

The potato cube has a ψp of 3.5 bar and a ψs of -6.5 bar.

Water potential: ψ=ψp​+ψs

​

ψp​= pressure potential

ψs​= solute potential

Assuming standard atmospheric pressure, which of the following is true?

The following is an excerpt from a scientific paper written by Fagarasanu & Rachubinski.

This physical compartmentalization of the cytoplasm permits the coexistence of a diverse range of chemical microenvironments, each precisely tailored for a defined set of biochemical reactions. Organelles constantly communicate with one another, which leads to the establishment of an effective and cooperative division of metabolic labor.

Which of the following best explains how compartmentalization within a cell leads to a “cooperative division of metabolic labor?”

Which of the following questions would best help determine if a cell has membrane-bound organelles?

In a study, researchers investigated the differences in pH between the inter-membrane space (IMS) of the mitochondrion and the cytosol. The results of their investigation are shown in the graph below.

Which of the following best explains why there is a difference in pH between the IMS and the cytosol?

Which of the following best explains how modified proteins are transported within a compartmentalized cell?

A student places a zucchini cube into an open container 0.50M sucrose solution. The temperature of the solution is kept steady at 25∘C.

What is the water potential of the zucchini cube?

Which of the following best explains why enzymatic reactions within the lysosome are compartmentalized?