Ch. 7 - Bio 112 Review Q's

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

How does cholesterol affect membrane fluidity?

At body temperature, it makes the membrane less fluid.

Why is energy required for active transport?

Because it moves solutes against their concentration gradients.

If a red blood cell and a plant cell were placed in seawater, what would happen to the 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 molecules is most likely to passively diffuse across the plasma membrane?

Carbon dioxide

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 statements about diffusion is true?

It is a passive process.

Which of the following statements about passive transport is correct?

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

Which of the following molecules are most abundant in the plasma membrane?

Phospholipids

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

The cells will decrease in size as water flows out of it.

A cell is placed into a solution and the cell shrinks. Which of the following is true regarding the solution?

The solution is hypertonic.

Which of the following is correct regarding peripheral proteins?

These proteins are found only on the surface of the plasma membrane.

Which of the following is correct regarding integral proteins?

These proteins exhibit both hydrophilic and hydrophobic properties.

Which of the following is a correct difference between active transport and facilitated diffusion?

Active transport requires energy from ATP, where facilitated diffusion does not.

Which of the following is a correct difference between active transport and facilitated diffusion?

Active transport uses ATP, where facilitated diffusion does not.

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

B; the diffusion gradient in cell B is steeper

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

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

Membrane proteins function primarily in cell-cell recognition.

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

The cell placed in a hypotonic solution.

The sodium-potassium pump _____.

Transports sodium ions out of the cell and transports potassium ions into the cell.

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

a large polar molecule

Which of the following substances would be most likely to pass through the plasma membrane without the help of a transport protein?

a nonpolar molecule, such as a hydrocarbon

What function do carbohydrates fulfill in the plasma membrane?

cell-to-cell recognition

In what type of environment is the concentration of solutes higher in the solution than in the cell?

hypertonic environment

Which of the following cell structures exhibits selective permeability between a cell and its external environment?

plasma membrane