CH. 7 Dynamic Study Module
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?
1.0 M
Which of the following is a correct difference between active transport and facilitated.
Active transport requires energy from ATP and facilitated diffusion does not.
Why is energy required for active transport?
Because it moves solutes against their concentration gradient
If a red blood cell and a plant cell were placed in sea water what would happen to the two types of cells?
Both cells would lose water
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
Which of the following processes and organelles account for the replacement of lipids and proteins lost from the plasma membrane?
Exocytosis and smooth and rough ER
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
Which of the following structural arrangements of the components in biological membranes facilitates the cell membrane's property of selective permeability?
Protein 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 quality of the membrane while the lateral and rotational movements of phospholipids contribute to its fluidity.
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
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
A nursing infant....
endocytosis
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 likely to diffuse through a plasma membrane without the help of a transport protein?
A large polar molecule
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
Which of the following statements about the role of phospholipids in the structure and function of biological membrane is correct?
Phospholipids for 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 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
How does cholesterol affect membrane fluidity?
At body temp it makes the membrane less fluid
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 concerning carbohydrates associated with the plasma membrane is correct?
Membrane carbohydrates function primarily in cell-cell recognition
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.
Which of the following statements about diffusion is true?
it is a passive process
The sodium-potassium pump____.
transports sodium ions out of the cell and transports potassium ions into the cell.
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
All cells have voltages across their membranes. This collage is called _____ and is often maintained by_____
membrane potential; electrogenic pumps