Biology Chapter 7

the internal solute concentration of a plant cell is about .8m. to demonstrate plasmolysis, it would be necessary to suspend the cell in what solution?

1.0m

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

A cell placed in a hypotonic solution

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

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 gradient

which of these statements describes some aspect of facilitated diffusion?

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

which of the following statements about diffusion is true

It's a passive process

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

a non-polar molecule, such as a hydrocarbon

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

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

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

active transport requires energy from ATP, and facilitated diffusion does not.

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 diffusion gradient in cell b is steeper.

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 loose 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

what function do carbohydrates fulfill in the plasma membrane?

cell-to-cell recognition

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

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 organelles accounts for the replacement of lipids and proteins lost from the plasma membrane?

exocytosis and smooth and rough ER

whoch 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 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 cell structures exhibits selective permeability between a cell and its external environment

plasma membrane

which of the following structural arrangements of the components in biological membranes facilitates the cell membranes property of selective permeability?

proteins embedded in two layers of phospholipids

how does the "fluid mosaic model" describe the structure of the plasma membrane

proteins in the membrane contribute to the mosaic p quality of the membrane while the lateral and rotational movements of phospholipids 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 water flows out of it.

the plasma membrane exhibits selective permeability. this means that ______

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

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

the solution is hypertonic