BIO CH 7

25 July 2022
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question
The sodium-potassium pump____.
answer
transports sodium ions out of the cell and transports potassium ions into the cell.
question
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?
answer
1.0 M
question
Which of the following is correct regarding peripheral proteins?
answer
These proteins are found only on the surface of the plasma membrane
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Which of the following statements about the role of phospholipids in the structure and function of biological membrane is correct?
answer
Phospholipids for a selectively permeable structure.
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Which of the following cell structures exhibits selective permeability between a cell and its external environment?
answer
Plasma membrane
question
A nursing infant....
answer
endocytosis
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A cell is placed into a solution and the cell shrinks. Which of the following is true regarding the solution?
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The solution is hypertonic
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Which of the following is correct regarding integral proteins?
answer
These proteins exhibit both hydrophilic and hydrophobic properties
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Why is energy required for active transport?
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Because it moves solutes against their concentration gradient
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All cells have voltages across their membranes. This collage is called _____ and is often maintained by_____
answer
membrane potential; electrogenic pumps
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Which of the following would be likely to diffuse through a plasma membrane without the help of a transport protein?
answer
A large polar molecule
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Which of the following statements about diffusion is true?
answer
it is a passive process
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Which of the following statements concerning carbohydrates associated with the plasma membrane is correct?
answer
Membrane carbohydrates function primarily in cell-cell recognition
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Which of the following molecules are most abundant in the plasma membrane?
answer
Phospholipids
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What function do carbohydrates fulfill in the plasma membrane
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Cell-to-cell recognition
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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?
answer
The cell will decrease in size as water flows out of it.
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If a red blood cell and a plant cell were placed in sea water what would happen to the two types of cells?
answer
Both cells would lose water
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How does the "fluid mosaic model" describe the structure of the plasma membrane?
answer
Proteins in the membrane contribute to the mosaic quality of the membrane while the lateral and rotational movements of phospholipids contribute to its fluidity.
question
Which of the following plant cells would exhibit the most turgor pressure?
answer
A cell placed in a hypotonic solution
question
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 __________.
answer
B: the diffusion gradient in cell B is steeper
question
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?
answer
endocytosis
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Which of the following is a correct difference between active transport and facilitated.
answer
Active transport requires energy from ATP and facilitated diffusion does not.
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Which of the following processes and organelles account for the replacement of lipids and proteins lost from the plasma membrane?
answer
Exocytosis and smooth and rough ER
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Which of the following substances would be most likely to pass through the plasma membrane without the help of a transport protein?
answer
A nonpolar molecule, such as a hydrocarbon
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Which of the following structural arrangements of the components in biological membranes facilitates the cell membrane's property of selective permeability?
answer
Protein embedded in two layers of phospholipids
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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.
answer
Channel; carrier
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How does cholesterol affect membrane fluidity?
answer
At body temp it makes the membrane less fluid
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Which of the following would be least likely to diffuse through a plasma membrane without the help of a transport protein?
answer
A large polar molecule
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The plasma membrane exhibits selective permeability. This means that_____.
answer
The plasma membrane allows some substances to flow through it more easily than others.
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Which of these statements describes some aspect of facilitated diffusion?
answer
Facilitated diffusion of solutes may occur through channel or transport proteins in the membrane
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Which of the following molecules is most likely to passively diffuse across the plasma membrane?
answer
Carbon dioxide
question
Which of the following statements about passive transport is correct?
answer
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.