Question 1

Which of the following is a characteristic feature of a carrier protein in a plasma membrane?

Accepted Answer

A) It is a peripheral membrane protein. 
B) It exhibits a specificity for a particular type of molecule. 
C) It requires the expenditure of cellular energy to function. 
D) It works against diffusion. 
E) It has few, if any, hydrophobic amino acids. 
A) It is a peripheral membrane protein. 
B) It exhibits a specificity for a particular type of molecule. 
C) It requires the expenditure of cellular energy to function. 
D) It works against diffusion. 
E) It has few, if any, hydrophobic amino acids.

Question 2

Cell membranes are asymmetrical. Which of the following is a most likely explanation?

Accepted Answer

A) The cell membrane forms a border between one cell and another in tightly packed tissues such as epithelium. 
B) Cell membranes communicate signals from one organism to another. 
C) Cell membrane proteins are determined as the membrane is being packaged in the ER and Golgi. 
D) The "innerness" and "outerness" of membrane surfaces are predetermined by genes. 
E) Proteins can only span cell membranes if they are hydrophobic. 
A) The cell membrane forms a border between one cell and another in tightly packed tissues such as epithelium. 
B) Cell membranes communicate signals from one organism to another. 
C) Cell membrane proteins are determined as the membrane is being packaged in the ER and Golgi. 
D) The "innerness" and "outerness" of membrane surfaces are predetermined by genes. 
E) Proteins can only span cell membranes if they are hydrophobic.

Question 3

Of the following functions, which is most important for the glycoproteins and glycolipids of animal cell membranes?

Accepted Answer

A) facilitated diffusion of molecules down their concentration gradients 
B) active transport of molecules against their concentration gradients 
C) maintaining the integrity of a fluid mosaic membrane 
D) maintaining membrane fluidity at low temperatures 
E) a cell's ability to distinguish one type of neighboring cell from another 
A) facilitated diffusion of molecules down their concentration gradients 
B) active transport of molecules against their concentration gradients 
C) maintaining the integrity of a fluid mosaic membrane 
D) maintaining membrane fluidity at low temperatures 
E) a cell's ability to distinguish one type of neighboring cell from another

Question 4

The following information should be used to answer the following questions.
Cystic fibrosis is a genetic disease in humans in which chloride ion channels in cell membranes are missing or nonfunctional.
-Which of the following would you expect to be a problem for someone with nonfunctional chloride channeling?

Accepted Answer

A) inadequate secretion of mucus 
B) buildup of excessive secretions in organs such as lungs 
C) buildup of excessive secretions in glands such as the pancreas 
D) sweat that includes no NaCl 
E) mental retardation due to low salt levels in brain tissue 
A) inadequate secretion of mucus 
B) buildup of excessive secretions in organs such as lungs 
C) buildup of excessive secretions in glands such as the pancreas 
D) sweat that includes no NaCl 
E) mental retardation due to low salt levels in brain tissue

Question 5

In receptor-mediated endocytosis, receptor molecules initially project to the outside of the cell. Where do they end up after endocytosis?

Accepted Answer

A) on the outside of vesicles 
B) on the inside surface of the cell membrane 
C) on the inside surface of the vesicle 
D) on the outer surface of the nucleus 
E) on the ER 
A) on the outside of vesicles 
B) on the inside surface of the cell membrane 
C) on the inside surface of the vesicle 
D) on the outer surface of the nucleus 
E) on the ER

Question 6

Which of the following statements is correct about diffusion?

Accepted Answer

A) It is very rapid over long distances. 
B) It requires an expenditure of energy by the cell. 
C) It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration. 
D) It is an active process in which molecules move from a region of lower concentration to one of higher concentration. 
E) It requires integral proteins in the cell membrane. 
A) It is very rapid over long distances. 
B) It requires an expenditure of energy by the cell. 
C) It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration. 
D) It is an active process in which molecules move from a region of lower concentration to one of higher concentration. 
E) It requires integral proteins in the cell membrane.

Question 7

The sodium-potassium pump is called an electrogenic pump because it

Accepted Answer

A) pumps equal quantities of Na+ and K+ across the membrane. 
B) pumps hydrogen ions out of the cell. 
C) contributes to the membrane potential. 
D) ionizes sodium and potassium atoms. 
E) is used to drive the transport of other molecules against a concentration gradient. 
A) pumps equal quantities of Na+ and K+ across the membrane. 
B) pumps hydrogen ions out of the cell. 
C) contributes to the membrane potential. 
D) ionizes sodium and potassium atoms. 
E) is used to drive the transport of other molecules against a concentration gradient.

Question 8

Refer to Figure 7.3 to answer the following questions.
The solutions in the arms of a U-tube are separated at the bottom of the tube by a selectively permeable membrane. The membrane is permeable to sodium chloride but not to glucose. Side A is filled with a solution of 0.4 M glucose and 0.5 M sodium chloride (NaCl), and side B is filled with a solution containing 0.8 M glucose and 0.4 M sodium chloride. Initially, the volume in both arms is the same.

-If you examine side A after 3 days, you should find

Accepted Answer

A) a decrease in the concentration of NaCl and glucose and an increase in the water level. 
B) a decrease in the concentration of NaCl, an increase in water level, and no change in the concentration of glucose. 
C) no net change in the system. 
D) a decrease in the concentration of NaCl and a decrease in the water level. 
E) no change in the concentration of NaCl and glucose and an increase in the water level. 
A) a decrease in the concentration of NaCl and glucose and an increase in the water level. 
B) a decrease in the concentration of NaCl, an increase in water level, and no change in the concentration of glucose. 
C) no net change in the system. 
D) a decrease in the concentration of NaCl and a decrease in the water level. 
E) no change in the concentration of NaCl and glucose and an increase in the water level.

Question 9

Which of these are not embedded in the lipid bilayer at all?

Accepted Answer

A) transmembrane proteins 
B) integral proteins 
C) peripheral proteins 
D) integrins 
E) glycoproteins 
A) transmembrane proteins 
B) integral proteins 
C) peripheral proteins 
D) integrins 
E) glycoproteins

Question 10

The difference between pinocytosis and receptor-mediated endocytosis is that

Accepted Answer

A) pinocytosis brings only water into the cell, but receptor-mediated endocytosis brings in other molecules as well. 
B) pinocytosis increases the surface area of the plasma membrane whereas receptor-mediated endocytosis decreases the plasma membrane surface area. 
C) pinocytosis is nonselective in the molecules it brings into the cell, whereas receptor-mediated endocytosis offers more selectivity. 
D) pinocytosis requires cellular energy, but receptor-mediated endocytosis does not. 
E) pinocytosis can concentrate substances from the extracellular fluid, but receptor-mediated endocytosis cannot. 
A) pinocytosis brings only water into the cell, but receptor-mediated endocytosis brings in other molecules as well. 
B) pinocytosis increases the surface area of the plasma membrane whereas receptor-mediated endocytosis decreases the plasma membrane surface area. 
C) pinocytosis is nonselective in the molecules it brings into the cell, whereas receptor-mediated endocytosis offers more selectivity. 
D) pinocytosis requires cellular energy, but receptor-mediated endocytosis does not. 
E) pinocytosis can concentrate substances from the extracellular fluid, but receptor-mediated endocytosis cannot.

Question 11

The presence of cholesterol in the plasma membranes of some animals

Accepted Answer

A) enables the membrane to stay fluid more easily when cell temperature drops. 
B) enables the animal to remove hydrogen atoms from saturated phospholipids. 
C) enables the animal to add hydrogen atoms to unsaturated phospholipids. 
D) makes the membrane less flexible, allowing it to sustain greater pressure from within the cell. 
E) makes the animal more susceptible to circulatory disorders. 
A) enables the membrane to stay fluid more easily when cell temperature drops. 
B) enables the animal to remove hydrogen atoms from saturated phospholipids. 
C) enables the animal to add hydrogen atoms to unsaturated phospholipids. 
D) makes the membrane less flexible, allowing it to sustain greater pressure from within the cell. 
E) makes the animal more susceptible to circulatory disorders.

Question 12

The formulation of a model for a structure or for a process serves which of the following purposes?

Accepted Answer

A) It asks a scientific question. 
B) It functions as a testable hypothesis. 
C) It records observations. 
D) It serves as a data point among results. 
E) It can only be arrived at after years of experimentation. 
A) It asks a scientific question. 
B) It functions as a testable hypothesis. 
C) It records observations. 
D) It serves as a data point among results. 
E) It can only be arrived at after years of experimentation.

Question 13

Proton pumps are used in various ways by members of every kingdom of organisms. What does this most probably mean?

Accepted Answer

A) Proton pumps must have evolved before any living organisms were present on the earth. 
B) Proton pumps are fundamental to all cell types. 
C) The high concentration of protons in the ancient atmosphere must have necessitated a pump mechanism. 
D) Cells with proton pumps were maintained in each Kingdom by natural selection. 
E) Proton pumps are necessary to all cell membranes. 
A) Proton pumps must have evolved before any living organisms were present on the earth. 
B) Proton pumps are fundamental to all cell types. 
C) The high concentration of protons in the ancient atmosphere must have necessitated a pump mechanism. 
D) Cells with proton pumps were maintained in each Kingdom by natural selection. 
E) Proton pumps are necessary to all cell membranes.

Question 14

You are working on a team that is designing a new drug. In order for this drug to work, it must enter the cytoplasm of specific target cells. Which of the following would be a factor that determines whether the molecule enters the cell?

Accepted Answer

A) blood or tissue type of the patient 
B) non-polarity of the drug molecule 
C) lack of charge on the drug molecule 
D) similarity of the drug molecule to other molecules transported by the target cells 
E) lipid composition of the target cells' plasma membrane 
A) blood or tissue type of the patient 
B) non-polarity of the drug molecule 
C) lack of charge on the drug molecule 
D) similarity of the drug molecule to other molecules transported by the target cells 
E) lipid composition of the target cells' plasma membrane

Question 15

Which of the following is one of the ways that the membranes of winter wheat are able to remain fluid when it is extremely cold?

Accepted Answer

A) by increasing the percentage of unsaturated phospholipids in the membrane 
B) by increasing the percentage of cholesterol molecules in the membrane 
C) by decreasing the number of hydrophobic proteins in the membrane 
D) by co-transport of glucose and hydrogen 
E) by using active transport 
A) by increasing the percentage of unsaturated phospholipids in the membrane 
B) by increasing the percentage of cholesterol molecules in the membrane 
C) by decreasing the number of hydrophobic proteins in the membrane 
D) by co-transport of glucose and hydrogen 
E) by using active transport

Question 16

Which of the following would likely move through the lipid bilayer of a plasma membrane most rapidly?

Accepted Answer

A) CO₂ 
B) an amino acid 
C) glucose 
D) K⁺ 
E) starch 
A) CO₂ 
B) an amino acid 
C) glucose 
D) K⁺ 
E) starch

Question 17

Use the diagram of the U-tube in Figure 7.2 to answer the questions that follow.
The solutions in the two arms of this U-tube are separated by a membrane that is permeable to water and glucose but not to sucrose. Side A is half filled with a solution of 2 M sucrose and 1 M glucose. Side B is half filled with 1 M sucrose and 2 M glucose. Initially, the liquid levels on both sides are equal.

-Celery stalks that are immersed in fresh water for several hours become stiff and hard. Similar stalks left in a salt solution become limp and soft. From this we can deduce that the cells of the celery stalks are

Accepted Answer

A) hypotonic to both fresh water and the salt solution. 
B) hypertonic to both fresh water and the salt solution. 
C) hypertonic to fresh water but hypotonic to the salt solution. 
D) hypotonic to fresh water but hypertonic to the salt solution. 
E) isotonic with fresh water but hypotonic to the salt solution. 
A) hypotonic to both fresh water and the salt solution. 
B) hypertonic to both fresh water and the salt solution. 
C) hypertonic to fresh water but hypotonic to the salt solution. 
D) hypotonic to fresh water but hypertonic to the salt solution. 
E) isotonic with fresh water but hypotonic to the salt solution.

Question 18

An animal cell lacking oligosaccharides on the external surface of its plasma membrane would likely be impaired in which function?

Accepted Answer

A) transporting ions against an electrochemical gradient 
B) cell-cell recognition 
C) maintaining fluidity of the phospholipid bilayer 
D) attaching to the cytoskeleton 
E) establishing the diffusion barrier to charged molecules 
A) transporting ions against an electrochemical gradient 
B) cell-cell recognition 
C) maintaining fluidity of the phospholipid bilayer 
D) attaching to the cytoskeleton 
E) establishing the diffusion barrier to charged molecules

Question 19

Which of the following types of molecules are the major structural components of the cell membrane?

Accepted Answer

A) phospholipids and cellulose 
B) nucleic acids and proteins 
C) phospholipids and proteins 
D) proteins and cellulose 
E) glycoproteins and cholesterol 
A) phospholipids and cellulose 
B) nucleic acids and proteins 
C) phospholipids and proteins 
D) proteins and cellulose 
E) glycoproteins and cholesterol

Question 20

For the following questions, match the labeled component of the cell membrane (Figure 7.1) with its description.

-fiber of the extracellular matrix

Accepted Answer

The answer of For the following questions, match the labeled...

Exam 7: Membrane Structure and Function

Which of the following is a characteristic feature of a carrier protein in a plasma membrane?

Cell membranes are asymmetrical. Which of the following is a most likely explanation?

Of the following functions, which is most important for the glycoproteins and glycolipids of animal cell membranes?

In receptor-mediated endocytosis, receptor molecules initially project to the outside of the cell. Where do they end up after endocytosis?

Which of the following statements is correct about diffusion?

The sodium-potassium pump is called an electrogenic pump because it

Which of these are not embedded in the lipid bilayer at all?

The difference between pinocytosis and receptor-mediated endocytosis is that

The presence of cholesterol in the plasma membranes of some animals

The formulation of a model for a structure or for a process serves which of the following purposes?

Proton pumps are used in various ways by members of every kingdom of organisms. What does this most probably mean?

You are working on a team that is designing a new drug. In order for this drug to work, it must enter the cytoplasm of specific target cells. Which of the following would be a factor that determines whether the molecule enters the cell?

Which of the following is one of the ways that the membranes of winter wheat are able to remain fluid when it is extremely cold?

Which of the following would likely move through the lipid bilayer of a plasma membrane most rapidly?

An animal cell lacking oligosaccharides on the external surface of its plasma membrane would likely be impaired in which function?

Which of the following types of molecules are the major structural components of the cell membrane?

For the following questions, match the labeled component of the cell membrane (Figure 7.1) with its description. -fiber of the extracellular matrix

Introduction: Themes in the Study of Life

The Chemical Context of Life

Water and the Fitness of the Environment

Carbon and the Molecular Diversity of Life

The Structure and Function of Large Biological Molecules

A Tour of the Cell

An Introduction to Metabolism

Cellular Respiration: Harvesting Chemical Energy

Photosynthesis

Cell Communication

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

From Gene to Protein

Control of Gene Expression

Viruses

Biotechnology

Genomes and Their Evolution

Descent With Modification: a Darwinian View of Life

The Evolution of Populations

The Origin of Species

The History of Life on Earth

Phylogeny and the Tree of Life

Bacteria and Archaea

Protists

Plant Diversity I: How Plants Colonized Land

Plant Diversity Ii: the Evolution of Seed Plants

Fungi

An Introduction to Animal Diversity

Invertebrates

Vertebrates

Plant Structure, Growth, and Development

Transport in Vascular Plants

Soil and Plant Nutrition

Angiosperm Reproduction and Biotechnology

Plant Responses to Internal and External Signals

Basic Principles of Animal Form and Function

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Osmoregulation and Excretion

Hormones and the Endocrine System

Animal Reproduction

Animal Development

Neurons, Synapses, and Signaling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behavior

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems

Conservation Biology and Restoration Ecology

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