Question 1

Water gets through the phospholipid bilayer only because:

Accepted Answer

A)  it is a small molecule. 
B)  it is nonpolar. 
C)  it is a large molecule. 
D)  it is polar. 
A)  it is a small molecule. 
B)  it is nonpolar. 
C)  it is a large molecule. 
D)  it is polar. A

Question 2

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, 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 large 
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 large B

Question 3

Which of the following statements about the phospholipids that make up the plasma membrane is true?

Accepted Answer

A)  The phosphate group is polar and therefore hydrophobic, meaning it loves to associate with water. 
B)  The phosphate group is polar and therefore hydrophobic, meaning it hates to associate with water. 
C)  The phosphate group is polar and therefore hydrophilic, meaning it loves to associate with water. 
D)  The phosphate group is nonpolar and therefore hydrophobic, meaning it hates to associate with water. 
E)  The phosphate group is polar and therefore hydrophilic, meaning it hates to associate with water. 
A)  The phosphate group is polar and therefore hydrophobic, meaning it loves to associate with water. 
B)  The phosphate group is polar and therefore hydrophobic, meaning it hates to associate with water. 
C)  The phosphate group is polar and therefore hydrophilic, meaning it loves to associate with water. 
D)  The phosphate group is nonpolar and therefore hydrophobic, meaning it hates to associate with water. 
E)  The phosphate group is polar and therefore hydrophilic, meaning it hates to associate with water. C

Question 4

Recognition proteins of the plasma membrane help in the immune response.

Accepted Answer

A) True 
 B)False

Question 5

Which of the following is a function of the plasma membrane?

Accepted Answer

A)  controlling the passage of substances into and out of the cell 
B)  creating the basic bilayer of the membrane 
C)  maintaining fluidity of the membrane 
D)  protection of the membrane 
A)  controlling the passage of substances into and out of the cell 
B)  creating the basic bilayer of the membrane 
C)  maintaining fluidity of the membrane 
D)  protection of the membrane

Question 6

The glycocalyx is made up of:

Accepted Answer

A)  sugars. 
B)  cholesterol. 
C)  nucleotides. 
D)  phospholipids. 
E)  proteins. 
A)  sugars. 
B)  cholesterol. 
C)  nucleotides. 
D)  phospholipids. 
E)  proteins.

Question 7

When a human cell is placed into water, it swells. This is said to be due to osmosis. What's happening to make the cell swell?

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)  The cell synthesizes new biological macromolecules as a protective response against a watery environment. 
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)  The cell synthesizes new biological macromolecules as a protective response against a watery environment.

Question 8

If you could label the hydrophobic portion of the plasma membrane with a red dye, you would find a red color:

Accepted Answer

A)  on either side of the bilayer, associated with the polar head groups 
B)  on the glycocalyx, outside the membrane. 
C)  dotted across the membrane wherever a transport protein was located. 
D)  on the interior portion of the plasma membrane bilayer, associated with the fatty acid tails. 
A)  on either side of the bilayer, associated with the polar head groups 
B)  on the glycocalyx, outside the membrane. 
C)  dotted across the membrane wherever a transport protein was located. 
D)  on the interior portion of the plasma membrane bilayer, associated with the fatty acid tails.

Question 9

What is the role of transport and channel proteins within the fluid mosaic of a plasma membrane?

Accepted Answer

A)  They prevent the passage of amino acids through the membrane. 
B)  They allow movement of salts and sugars through the plasma membrane. 
C)  They identify the cell. 
D)  They may set off cellular changes, such as cell division or hormonal secretion. 
E)  They allow movement of water through the plasma membrane. 
A)  They prevent the passage of amino acids through the membrane. 
B)  They allow movement of salts and sugars through the plasma membrane. 
C)  They identify the cell. 
D)  They may set off cellular changes, such as cell division or hormonal secretion. 
E)  They allow movement of water through the plasma membrane.

Question 10

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

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. 
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.

Question 11

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 tend to invert its normal structure by placing the polar head groups on the inside of the bilayer and the nonpolar fatty acid tails outside. 
E)  The phospholipid bilayer would split into two separate layers, which each would be maintained in the oil. 
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 tend to invert its normal structure by placing the polar head groups on the inside of the bilayer and the nonpolar fatty acid tails outside. 
E)  The phospholipid bilayer would split into two separate layers, which each would be maintained in the oil.

Question 12

Refer to the figure above and then answer the question that follows.
-For this type of transport to take place, which of the following must be true about the interior and exterior environments?

Accepted Answer

A)  The amount of glucose outside the cell must be less than the interior concentration. 
B)  The glucose concentration must be higher outside the cell than inside the cell. 
C)  The glucose concentrations on both sides of the cell are the same. 
D)  A transport protein is involved, so it doesn't matter what the concentrations of glucose on either side of the membrane. 
A)  The amount of glucose outside the cell must be less than the interior concentration. 
B)  The glucose concentration must be higher outside the cell than inside the cell. 
C)  The glucose concentrations on both sides of the cell are the same. 
D)  A transport protein is involved, so it doesn't matter what the concentrations of glucose on either side of the membrane.

Question 13

When returning home from vacation, you find your favorite plant drooped over in its planter. Remembering your biology studies, you immediately water your plant, and it soon stands back up. Explain why lack of water caused the plant to droop and why watering it caused it to stand back up.

Accepted Answer

If a plant doesn't receive eno

Question 14

The continuous part of the plasma membrane is the:

Accepted Answer

A)  carbohydrate. 
B)  phospholipid bilayer. 
C)  nucleotides. 
D)  protein. 
E)  starches. 
A)  carbohydrate. 
B)  phospholipid bilayer. 
C)  nucleotides. 
D)  protein. 
E)  starches.

Question 15

If you wanted to change the fluidity of the membrane you would need to:

Accepted Answer

A)  remove the cholesterol. 
B)  remove the integral proteins. 
C)  remove the glycocalyx. 
D)  increase the number of phospholipids. 
E)  decrease the number of phospholipids. 
A)  remove the cholesterol. 
B)  remove the integral proteins. 
C)  remove the glycocalyx. 
D)  increase the number of phospholipids. 
E)  decrease the number of phospholipids.

Question 16

Explain why red blood cells will burst if you put them into freshwater, but plant cells put into freshwater will not burst.

Accepted Answer

Red blood cells will burst because water

Question 17

Which type of proteins are involved in nutrient transport and why?

Accepted Answer

A)  integral proteins, because they span the membrane and thereby are able to carry nutrients across the membrane 
B)  peripheral proteins, because they are smaller and can travel across the membrane, thereby carrying nutrients across the membrane 
C)  integral proteins, because they are smaller and can travel across the membrane, thereby carrying nutrients across the membrane 
D)  peripheral proteins, because they span the membrane and thereby are able to carry nutrients across the membrane 
E)  both integral and peripheral proteins, because they can both span the membrane and thereby are able to carry nutrients across the membrane 
A)  integral proteins, because they span the membrane and thereby are able to carry nutrients across the membrane 
B)  peripheral proteins, because they are smaller and can travel across the membrane, thereby carrying nutrients across the membrane 
C)  integral proteins, because they are smaller and can travel across the membrane, thereby carrying nutrients across the membrane 
D)  peripheral proteins, because they span the membrane and thereby are able to carry nutrients across the membrane 
E)  both integral and peripheral proteins, because they can both span the membrane and thereby are able to carry nutrients across the membrane

Question 18

Phospholipids are:

Accepted Answer

A)  only polar molecules. 
B)  only nonpolar molecules. 
C)  both polar and nonpolar. 
D)  oil. 
A)  only polar molecules. 
B)  only nonpolar molecules. 
C)  both polar and nonpolar. 
D)  oil.

Question 19

If you could add a colored label to one phospholipid in the cell's plasma membrane to observe this molecule, you would see this phospholipid molecule:

Accepted Answer

A)  moving rapidly back and forth across the surface of the membrane in which it was initially located. 
B)  locked in place by its tightly packed neighbors in the plasma membrane. 
C)  converted back and forth between a receptor protein and a phospholipid. 
D)  moving back and forth between the membrane and the surrounding watery solution. 
E)  flipping back and forth across the membrane. 
A)  moving rapidly back and forth across the surface of the membrane in which it was initially located. 
B)  locked in place by its tightly packed neighbors in the plasma membrane. 
C)  converted back and forth between a receptor protein and a phospholipid. 
D)  moving back and forth between the membrane and the surrounding watery solution. 
E)  flipping back and forth across the membrane.

Question 20

Which of the following is a function of proteins in cells?

Accepted Answer

A)  transports nutrients into a cell 
B)  produces vesicles for transport 
C)  maintains fluidity 
D)  gives plant cells their shape 
E)  acts to hold phospholipids together within the bilayer 
A)  transports nutrients into a cell 
B)  produces vesicles for transport 
C)  maintains fluidity 
D)  gives plant cells their shape 
E)  acts to hold phospholipids together within the bilayer

Exam 5: Lifes Border: The Plasma Membrane

Water gets through the phospholipid bilayer only because:

Which of the following statements about the phospholipids that make up the plasma membrane is true?

Recognition proteins of the plasma membrane help in the immune response.

Which of the following is a function of the plasma membrane?

The glycocalyx is made up of:

When a human cell is placed into water, it swells. This is said to be due to osmosis. What's happening to make the cell swell?

If you could label the hydrophobic portion of the plasma membrane with a red dye, you would find a red color:

What is the role of transport and channel proteins within the fluid mosaic of a plasma membrane?

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

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

Refer to the figure above and then answer the question that follows. -For this type of transport to take place, which of the following must be true about the interior and exterior environments?

When returning home from vacation, you find your favorite plant drooped over in its planter. Remembering your biology studies, you immediately water your plant, and it soon stands back up. Explain why lack of water caused the plant to droop and why watering it caused it to stand back up.

The continuous part of the plasma membrane is the:

If you wanted to change the fluidity of the membrane you would need to:

Explain why red blood cells will burst if you put them into freshwater, but plant cells put into freshwater will not burst.

Which type of proteins are involved in nutrient transport and why?

Phospholipids are:

If you could add a colored label to one phospholipid in the cell's plasma membrane to observe this molecule, you would see this phospholipid molecule:

Which of the following is a function of proteins in cells?

A Guide to the Natural World

Chemistry, Water and PH

Lifes Components: Biological Molecules

Lifes Home: The Cell

An Introduction to Energy

Deriving Energy From Food

Photosynthesis

Genetics and Cell Division

Preparing for Sexual Reproduction: Meiosis

Mendel and His Discoveries

Chromosomes and Inheritance

Dna Structure and Replication

Transcription Translation and Regulation

Biotechnology

Charles Darwin, Evolutionary Thought, and the Evidence for Evolution

Microevolution

Macroevolution

The History of Life on Earth

The Evolution of Human Beings

The Diversity of Life 1

The Diversity of Life 2

The Diversity of Life 3

An Introduction to Flowering Plants

Form and Function in Flowering Plants

The Integumentary Skeletal and Muscular Systems

The Nervous and Endocrine System

The Immune System

Blood and Breath

Digestion, Nutrition and Elimination

Animal Development

Human Reproduction

Populations in Ecology

Communities in Ecology

Ecosystems and Biomes

Animal Behavior

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