Ch. 7 practice test

What statement about diffusion is true

It is a passive process

Which of the following molecules is the most abundant in the plasma membrane

Phospholipids

the sodium potassium pump

transports sodium ions OUT of the cell and potassium ions INTO the cell

The internal solute concentration of a plant cell is about 0.8M. To demonstrate plasmolysis, it would be necessary to suspend the cell in what solution?

1.0M

What would be least likely to diffuse through a plasma membrane without the help of a transport protein

A large polar molecule

What would likely pass through the plasma membrane without the help of a transport protein

A nonpolar molecule, such as a hydrocarbon

What is the difference between active and passive transport

Active- uses ATP passive- no energy

Cells A and B are the same size, shape, and temperature, but cell A is metabolically less active than cell B; cell B is actively converting oxygen to water in cellular respiration. Oxygen will diffuse more rapidly into cell __________ because __________.

B; the gradient diffusion in cell B is steeper

If a red blood cell and a plant cell were placed in seawater, what would happen to these two types of cells

Both cells would lose water; the red blood cell would shrivel, and the plant plasma membrane would pull away from the cell wall.

Which of the following statements concerning carbohydrates associated the plasma membrane is correct

Carbohydrates mainly function in cell-to-cell recognition

Which would be most likely to diffuse across a plasma membrane

Carbon dioxide gases pass through easily

What function do carbohydrates fulfill in the plasma membrane

Cell-to-cell recognition

A nursing infant is able to obtain disease-fighting antibodies, which are large protein molecules, from its mother's milk. These molecules probably enter the cells lining the baby's digestive tract via which process?

Endocytosis

Which of the following processes and organelle(s) accounts for the replacement of lipids and proteins lost from the plasma membrane?

Exocytosis and smooth and rough ER

What describes some aspect of facilitated diffusion

Facilitated diffusion of a solute may occur through channel or transport proteins in the membrane

What statement about passive transport is correct

Passive transport permits the solute to move in either direction, but the net movement of the population of the solute molecules occurs DOWN the concentration gradient

Which of the following statements about the role of phospholipids in the structure and function of biological membranes is correct?

Phospholipids form a selectively permeable structure

Which structural arrangement in biological membranes facilitates the cell membrane's property of selective permeability

Proteins embedded in two layers of phosolipids

How does the "fluid mosaic model" describe a structure of the plasma membrane

Proteins in the membrane contribute to the mosaic quality of the membrane while the lateral and rotational movements of phosolipids contribute to its fluidity

Red blood cells contain approximately a 2% concentration of solutes. A red blood cell is placed into a solution that contains a 4% concentration of solutes to which the cell is not permeable. What will happen to the red blood cell?

The cell will decrease in size as the water flows out of it

A cell is placed in a solution and shrinks. What is true about the solution

The solution is hypertonic

Which is correct about integral proteins

These proteins exhibit both hydrophilic and hydrophobic properties

What is correct about peripheral proteins

They are found on the surface of plasma membrane, not attached to cell

Which of the following plant cells would exhibit the most turgor pressure

a cell placed in a hypotonic solution

How does cholesterol affect membrane fluidity

at body temperature, cholesterol makes the membrane LESS fluid

In facilitated diffusion, __________ proteins provide openings in the plasma membrane for substances to flow through without changing structure, and __________ proteins allow passage of substances through the plasma membrane after undergoing a subtle change in shape.

channel; carrier

All cells have voltages across their membranes. This voltage is called____ and is often maintained by

membrane potential; electrogenic pumps