The sodium-potassium pump____. |
transports sodium ions out of the cell and transports potassium ions into the cell. |
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 correct regarding peripheral proteins? |
These proteins are found only on the surface of the plasma membrane |
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 |
A nursing infant…. |
endocytosis |
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 integral proteins? |
These proteins exhibit both hydrophilic and hydrophobic properties |
Why is energy required for active transport? |
Because it moves solutes against their concentration gradient |
All cells have voltages across their membranes. This collage is called _____ and is often maintained by_____ |
membrane potential; electrogenic pumps |
Which of the following would be likely to diffuse through a plasma membrane without the help of a transport protein? |
A large polar molecule |
Which of the following statements about diffusion is true? |
it is a passive process |
Which of the following statements concerning carbohydrates associated with the plasma membrane is correct? |
Membrane carbohydrates function primarily in cell-cell recognition |
Which of the following molecules are most abundant in the plasma membrane? |
Phospholipids |
What function do carbohydrates fulfill in the plasma membrane |
Cell-to-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. |
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 |
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. |
Which of the following plant cells would exhibit the most turgor pressure? |
A cell placed in a hypotonic solution |
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 |
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 is a correct difference between active transport and facilitated. |
Active transport requires energy from ATP and facilitated diffusion does not. |
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 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 |
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 |
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 |
How does cholesterol affect membrane fluidity? |
At body temp it makes the membrane less fluid |
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 |
The plasma membrane exhibits selective permeability. This means that_____. |
The plasma membrane allows some substances to flow through it more easily than others. |
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 molecules is most likely to passively diffuse across the plasma membrane? |
Carbon dioxide |
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. |
BIO CH 7
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