Question 1

The central vacuoles of some plant cells you are studying fill with water and press the cell contents against their cell walls because of osmosis.What can you predict about the concentration of solutes in the solution that bathes the turgid plant cells?

Accepted Answer

A)  The concentration of solutes outside the cell must be significantly lower than the concentration within the cell.
B)  The concentration of solutes outside the cell must be significantly higher than the concentration within the cell.
C)  There must be no solutes either outside or inside the cell.
D)  The concentration of solutes outside the cell must be about the same as that of seawater.
E)  The concentration of solutes outside the cell can't be predicted, because it's the concentration inside the cell that's important.F) A) and C)
G) A) and B)

Question 2

The ________ of a phospholipid molecule will seek water,whereas the ________ of the molecules will avoid water.

Accepted Answer

A)  tail; head
B)  head; tail
C)  hydrophobic portion; hydrophilic portion
D)  fatty acid; phosphate groupE) B) and C)
F) A) and C)

Question 3

Diffusion is a process by which a substance:

Accepted Answer

A)  goes from lesser to greater concentration.
B)  goes down its concentration gradient.
C)  goes up its concentration gradient.
D)  is at equilibrium.E) B) and C)
F) A) and D)

Question 4

Cholesterol helps to maintain the correct fluidity of the plasma membrane.

Accepted Answer

A) True 
 B)False

Question 5

Red blood cells placed in pure water will swell and burst.What process is causing this to happen?

Accepted Answer

A)  Water is diffusing across the plasma membrane from a region of high (outside the cell) to low (inside the cell) "free" water concentration.
B)  Water is being pulled into the cell by the cell's solutes.
C)  Water is diffusing across the plasma membrane from a region of low (outside the cell) to high (inside the cell) "free" water concentration.
D)  Solutes are being drawn into the cell across the plasma membrane.
E)  Ions are diffusing across the plasma membrane and destabilizing the phospholipids.F) A) and E)
G) A) and D)

Question 6

A substance moving down the concentration gradient is an example of active transport.

Accepted Answer

A) True 
 B)False

Question 7

Membrane proteins perform all of the following functions except:

Accepted Answer

A)  structural support.
B)  cell recognition.
C)  communication.
D)  transport.
E)  maintainance of membrane fluidity.F) A) and B)
G) B) and E)

Question 8

If you transferred a phospholipid bilayer from water to oil,what effect would this have on the membrane?

Accepted Answer

A)  The membrane would become very rigid.
B)  The membrane would form four layers instead of its normal two.
C)  The membrane would be unaffected by the oil.
D)  The membrane would invert its normal structure by positioning the heads on the inside of the bilayer and the fatty-acid tails outside.
E)  The phospholipid bilayer would split into two separate layers, which each would be maintained in the oil.F) D) and E)
G) A) and B)

Question 9

Integral proteins always extend completely through the plasma membrane.

Accepted Answer

A) True 
 B)False

Question 10

The 1985 Nobel Prize in Physiology or Medicine was awarded to Michael Brown and Joseph Goldstein for their work on cholesterol metabolism.Brown and Goldstein investigated the cause of remarkably high levels of circulating cholesterol found in certain families.Just as remarkable was the high incidence of heart disease in these families.What Brown and Goldstein found was not what might be expected-these individuals did not make too much cholesterol.Instead,most of these people had defects in receptor-mediated endocytosis (RME) .What could possibly link high cholesterol levels in the blood and defective RME in these patients?

Accepted Answer

A)  Cholesterol was being secreted from cells by RME at too high a rate and therefore accumulated in the blood.
B)  Cholesterol was not transported into cells by RME and therefore accumulated in the blood.
C)  Cholesterol was being secreted by facilitated diffusion at too high a rate and therefore accumulated in the blood.
D)  Cholesterol was not transported into cells by active transport proteins and therefore accumulated in the blood.
E)  Cholesterol was not transported into cells by facilitated diffusion and therefore accumulated in the blood.F) D) and E)
G) A) and B)

Question 11

Cholesterol is a hormone receptor in the plasma membrane.

Accepted Answer

A) True 
 B)False

Question 12

A main function of the carbohydrates that form the glycocalyx is to:

Accepted Answer

A)  move large molecules in and out of the cell.
B)  regulate water movement into the cell.
C)  bind cell membranes to the cytoskeleton.
D)  act as binding sites for signaling molecules.
E)  maintain the proper fluidity of the plasma membrane.F) D) and E)
G) All of the above

Question 13

Signals sent between cells reach a cell at receptor proteins.

Accepted Answer

A) True 
 B)False

Question 14

Osmosis is an example of passive transport.

Accepted Answer

A) True 
 B)False

Question 15

The plasma membrane is composed of phospholipids,which are free to move laterally,and is peppered with both stationary and mobile proteins.This view of the plasma membrane is known as the:

Accepted Answer

A)  peppered membrane model.
B)  phospholipid bilayer model.
C)  fluid-mosaic model.
D)  semipermeable membrane model.E) A) and C)
F) A) and B)

Question 16

The ________ functions in cell lubrication,adhesion,and signaling.

Accepted Answer

The answer of The ________ functions in cell lubrication,adhesion,and signaling....

Question 17

Active transport:

Accepted Answer

A)  moves only large molecules into the cell.
B)  causes the production of ATP within the cell.
C)  increases the concentration of solute inside the cell.
D)  moves substances against their concentration gradient.E) A) and C)
F) A) and B)

Question 18

The plasma membrane is a semipermeable membrane.This means that it is:

Accepted Answer

A)  permeable to small molecules except water.
B)  permeable to small and uncharged molecules but not to larger or charged substances.
C)  only permeable to cholesterol.
D)  permeable to large charged molecules but not to small uncharged molecules.E) A) and B)
F) C) and D)

Question 19

Calcium ions (Ca²⁺) are present in the endoplasmic reticulum at concentrations 1,000 times higher than in the cytosol (the gel-like part of the cell outside organelles) .One protein on the endoplasmic reticulum membrane is devoted to allowing Ca²⁺ to move from the endoplasmic reticulum to the cytosol,and another protein moves Ca²⁺ from the cytosol to the endoplasmic reticulum.These processes are not trivial-Ca²⁺ released into the cytosol allows,for example,for muscle contraction and communication between nerve cells.In this pair of Ca²⁺ transport proteins,you would predict that the protein moving Ca²⁺ from the endoplasmic reticulum to the cytosol ________,and the protein that moves Ca²⁺ from cytosol to the endoplasmic reticulum ________.

Accepted Answer

A)  transports calcium slowly; transports calcium rapidly
B)  works without ATP; requires ATP
C)  requires ATP; works without ATP
D)  is large; is small
E)  is small; is largeF) A) and D)
G) All of the above

Question 20

The outer living limit of the cell is called the:

Accepted Answer

A)  cell wall.
B)  edge.
C)  plastid.
D)  plasma membrane.E) C) and D)
F) B) and C)

Exam 5: Lifes Border: the Plasma Membrane

Correct Answer
verified

Integral proteins always extend completely through the plasma membrane.

Correct Answer
verified

Correct Answer
verified

If you transferred a phospholipid bilayer from water to oil,what effect would this have on the membrane?

Correct Answer
verified

The central vacuoles of some plant cells you are studying fill with water and press the cell contents against their cell walls because of osmosis.What can you predict about the concentration of solutes in the solution that bathes the turgid plant cells?

Correct Answer
verified

Osmosis is an example of passive transport.

Correct Answer
verified

The plasma membrane is composed of phospholipids,which are free to move laterally,and is peppered with both stationary and mobile proteins.This view of the plasma membrane is known as the:

Correct Answer
verified

A main function of the carbohydrates that form the glycocalyx is to:

Correct Answer
verified

The of a phospholipid molecule will seek water,whereas the of the molecules will avoid water.

Correct Answer
verified

The plasma membrane is a semipermeable membrane.This means that it is:

Correct Answer
verified

Membrane proteins perform all of the following functions except:

Correct Answer
verified

Active transport:

Correct Answer
verified

Signals sent between cells reach a cell at receptor proteins.

Correct Answer
verified

The ________ functions in cell lubrication,adhesion,and signaling.

Correct Answer
verified

Cholesterol helps to maintain the correct fluidity of the plasma membrane.

Correct Answer
verified

Red blood cells placed in pure water will swell and burst.What process is causing this to happen?

Correct Answer
verified

The outer living limit of the cell is called the:

Correct Answer
verified

Cholesterol is a hormone receptor in the plasma membrane.

Correct Answer
verified

Diffusion is a process by which a substance:

Correct Answer
verified

A substance moving down the concentration gradient is an example of active transport.

Correct Answer
verified

Exam 5: Lifes Border: the Plasma Membrane

Correct AnswerverifiedShow Answer

Integral proteins always extend completely through the plasma membrane.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

If you transferred a phospholipid bilayer from water to oil,what effect would this have on the membrane?

Correct AnswerverifiedShow Answer

The central vacuoles of some plant cells you are studying fill with water and press the cell contents against their cell walls because of osmosis.What can you predict about the concentration of solutes in the solution that bathes the turgid plant cells?

Correct AnswerverifiedShow Answer

Osmosis is an example of passive transport.

Correct AnswerverifiedShow Answer

The plasma membrane is composed of phospholipids,which are free to move laterally,and is peppered with both stationary and mobile proteins.This view of the plasma membrane is known as the:

Correct AnswerverifiedShow Answer

A main function of the carbohydrates that form the glycocalyx is to:

Correct AnswerverifiedShow Answer

The ________ of a phospholipid molecule will seek water,whereas the ________ of the molecules will avoid water.

Correct AnswerverifiedShow Answer

The plasma membrane is a semipermeable membrane.This means that it is:

Correct AnswerverifiedShow Answer

Membrane proteins perform all of the following functions except:

Correct AnswerverifiedShow Answer

Active transport:

Correct AnswerverifiedShow Answer

Signals sent between cells reach a cell at receptor proteins.

Correct AnswerverifiedShow Answer

The ________ functions in cell lubrication,adhesion,and signaling.

Correct AnswerverifiedShow Answer

Cholesterol helps to maintain the correct fluidity of the plasma membrane.

Correct AnswerverifiedShow Answer

Red blood cells placed in pure water will swell and burst.What process is causing this to happen?

Correct AnswerverifiedShow Answer

The outer living limit of the cell is called the:

Correct AnswerverifiedShow Answer

Cholesterol is a hormone receptor in the plasma membrane.

Correct AnswerverifiedShow Answer

Diffusion is a process by which a substance:

Correct AnswerverifiedShow Answer

A substance moving down the concentration gradient is an example of active transport.

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
verified

The of a phospholipid molecule will seek water,whereas the of the molecules will avoid water.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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