BIO 111 Chapter 5

Which of the following would diffuse through the lipid bilayer of a plasma membrane most rapidly?

O2

A protein that spans the phospholipid bilayer one or more times is

a transmembrane protein

In which case would osmosis occur?

A skin cell in a hypotonic solution

You are observing a newly discovered form of protist, and you see an organelle suddenly decrease in volume. What has happened?

A.The cell was osmoregulating. B.The cell used its contractile vacuole. C.The cell was counteracting osmosis. D.The cell was avoiding bursting. E.All of the choices are correct. E

Movement of water out of a cell that has been placed in a hypertonic solution is

A.active transport .B.passive transport. C.diffusion. D.B and C. E.A and C. D

A living cell has a gradient across its membrane that is which of the following?

A.electrical B.physical C.light-driven D.chemical E.A and D E

Chemical analysis of a cellular membrane would normally reveal the presence of

A.sugars. B.proteins. C.lipids. D.nucleic acids. E.A-C. E

If you were studying a cell undergoing lots of active transport, which nucleotide would you expect to find in greatest abundance?

ATP

Which of the following statements correctly describes the normal tonicity relationships between typical plant and animal cells and their respective environments?

Animal cells are generally in an isotonic solution, and plant cells are generally in a hypotonic solution.

Which of the following statements is TRUE with regard to this animation?

Both sodium and potassium ions are transported against their concentration gradients

Five dialysis bags, constructed from a semipermeable membrane that is impermeable to sucrose, were filled with various concentrations of sucrose and then placed in separate beakers containing an initial concentration of 0.6 M sucrose solution. At 10-minute intervals, the bags were massed (weighed) and the percent change in mass of each bag was graphed. Refer to the figure to answer the following question. Which line in the graph represents the bag that contained a solution isotonic to the 0.6 M solution at the beginning of the experiment?

C

Which of the following is a characteristic feature of a carrier protein in a plasma membrane?

It exhibits a specificity for a particular type of molecule.

Which of the following statements about diffusion is correct?

It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration.

Which molecule will diffuse most quickly across a lipid bilayer membrane?

O2

Cells such as bacteria are taken up by other cells such as immune cells by which process?

Phagocytosis

If you place a culture of animal cells (called fibroblasts) into a container filled with molecules of red dye that have a strong negative charge, and the dye ends up inside the cell, what is the most likely explanation for the uptake?

Pinocytosis

Proton pumps are used in various ways by members of every domain of organisms: Bacteria, Archaea, and Eukarya. What does this most probably mean?

Proton gradients across a membrane were used by cells that were the common ancestor of all three domains of life.

A semipermeable membrane is placed between the following solutions.

Solution A: 1.4% (m/v) starch

A semipermeable membrane is placed between the following solutions.

Solution D: 12.4% (m/v) NaCl

If you placed an algal cell that had been living in a marine aquarium with oceanic fish into a glass of pure water, what would happen?

The cell would take up water

A patient has had a serious accident and lost a lot of blood. In an attempt to replenish body fluids, distilled water equal to the volume of blood lost − is transferred directly into one of his veins. What will be the most probable result of this transfusion?

The patient's red blood cells will swell because the blood fluid has become hypotonic compared to the cells.

Which of the following is most likely true of a protein that cotransports glucose and sodium ions into the intestinal cells of an animal?

Transport of sodium ions down their electrochemical gradient facilitates the transport of glucose against its concentration gradient.

Which of the following would diffuse through the lipid bilayer of a plasma membrane most slowly, if at all?

an amino acid

The fluid mosaic model of the membrane proposed that membranes

consist of protein molecules embedded in a fluid bilayer of phospholipids.

A primary function of cholesterol in the plasma membranes of some animals is to

enable the membrane to stay fluid more easily when the temperature drops.

This cell is in a(n) _____ solution. The cell membrane separating the extracellular fluid and the cytoplasm of a cell. The concentration of the solute is higher outside the cell. The cell is shown in two states: when it was just placed in this solute and over time. Over time, the cell decreased in size.

hypertonic

You know that this cell is in a(n) _____ solution because it _____. A cell in a solution. There are much more particles outside the cell than inside. Water moves outside the cell, and the cell is wrinkled.

hypertonic solution... lost water

You know that this cell is in a(n) _____ solution because the cell _____. The cell membrane separating the extracellular fluid and the cytoplasm of a cell. The concentration of the solute is higher outside the cell. The cell is shown in two states: when it was just placed in this solute and over time. Over time, the cell increased in size.

hypotonic... swelled

Water passes quickly through cell membranes because

it moves through aquaporin channel proteins.

The sodium-potassium pump generates the following concentration gradients across the plasma membrane:

low [Na+] and high [K+] inside the cell and high [Na+] and low [K+] outside.

Which of the following membrane activities requires energy from ATP hydrolysis?

movement of sodium ions from a lower concentration in a mammalian cell to a higher concentration in the extracellular fluid

In receptor-mediated endocytosis, receptor molecules are initially localized on the outer surface of the plasma membrane. Where do the receptors end up following endocytosis?

on the inside surface of a vesicle

What name is given to the process by which water crosses a selectively permeable membrane?

osmosis

Facilitated diffusion is a type of _______.

passive transport

The primary structural components of the cell membrane are

phospholipids and proteins

The difference between pinocytosis and receptor-mediated endocytosis is that

pinocytosis is nonselective in the molecules it brings into the cell, whereas receptor-mediated endocytosis is highly selective.

Structure A is a _____. The cell membrane with an integral molecule that consists of two similar parts with a specific recess. There are many particles in the extracellular fluid. One of these particles is labeled A.

solute

Submerging a plant cell in distilled water will result in

the cell becoming turgid.

Structure B is a _____. The cell membrane with an integral molecule marked B, which consists of two similar parts with a specific recess. The extracellular fluid contains many particles.

transport protein