DSM Ch. 7

The solution is hypertonic

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

Endocytosis

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?

membrane potential; electrogenic pumps

All cells have voltages across their membranes. This voltage is called a(n) __________ 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 __________.

At body temperature, it makes the membrane less fluid.

How does cholesterol affect membrane fluidity?

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

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

Both cells would lose water

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

Carrier

In facilitated diffusion, __________ proteins allow passage of substances through the plasma membrane after undergoing a subtle change in shape.

Channel

In facilitated diffusion, __________ proteins provide openings in the plasma membrane for substances to flow through without changing structure

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

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?

1.0 M

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?

Cell-to-cell recognition

What function do carbohydrates fulfill in the plasma membrane?

Plasma membrane

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

Active transport requires energy from ATP, facilitated diffusion does not

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

These proteins exhibit both hydrophilic and hydrophobic properties.

Which of the following is correct regarding integral proteins?

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

Which of the following is correct regarding peripheral proteins?

Phospholipids

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

Carbon dioxide

Which of the following molecules 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?

Exocytosis and smooth and rough ER

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

It is a passive process.

Which of the following statements about diffusion is true?

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 statements about passive transport is correct?

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?

Membrane carbohydrates function primarily in cell-cell recognition

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

Proteins embedded in two layers of phospholipids

Which of the following structural arrangements of the components in biological membranes facilitates the cell membrane's property of selective permeability?

A nonpolar molecule, such as a hydrocarbon

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

A large polar molecule

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

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

Which of these statements describes some aspect of facilitated diffusion?

Because 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