Bio Chapter 7

The solution is hypertonic

A cell is placed into a solution and the cell shrinks. What is true about this solution?

Endocytosis

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

Membrane potential; electrogenic pumps

All cells have voltages across their membrane. This voltage is called a _______ and is often maintained by _______

B; the diffusion gradient in cell B is steeper

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 ________

Proteins in the membrane contribute to the mosaic quality of the membrane while the lateral and rational movements of phospholipids contribute to its fluidity

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

Channel; carrier

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.

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

1.0 M

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

The plasma allows some substances to flow through it more easily than others

The plasma membrane exhibits selective permeability. This means that _______

Active transport requires energy from ATP, and facilitated diffusion does not

What is a difference between active transport and facilitated diffusion?

It is a passive process

What is true about diffusion?

They are found only on the surface of the plasma membrane

What is true about peripheral proteins?

Phospholipids

What molecules are most abundant in the plasma membrane?

A large polar molecule

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

Carbon dioxide

Which molecule is most likely to passively diffuse across the plasma membrane?

A cell placed in a hypotonic solution

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

Phospholipids form a selectively permeable structure

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

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

Which statement describes some aspect of facilitated diffusion?

It moves solutes against their concentration gradient

Why is energy required for active transport?

Sodium-potassium pump

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