Question 1

Nitrous oxide gas molecules diffusing across a cell's plasma membrane is an example of

Accepted Answer

A) diffusion across the lipid bilayer. 
B) facilitated diffusion. 
C) active transport. 
D) osmosis. 
E) cotransport. 
A) diffusion across the lipid bilayer. 
B) facilitated diffusion. 
C) active transport. 
D) osmosis. 
E) cotransport. A

Question 2

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.Refer to the figure to answer the following questions.
  
-If you examine side A after three 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. D

Question 3

For the following questions,match the labelled component of the cell membrane in the figure with its description.
  
-Which component is a microfilament of the cytoskeleton?

Accepted Answer

A) A 
B) B 
C) C 
D) D 
E) E 
A) A 
B) B 
C) C 
D) D 
E) E C

Question 4

According to the fluid mosaic model of cell membranes,which of the following is a true statement about membrane phospholipids?

Accepted Answer

A) They can move laterally along the plane of the membrane. 
B) They frequently flip-flop from one side of the membrane to the other. 
C) They occur in an uninterrupted bilayer, with membrane proteins restricted to the surface of the membrane. 
D) They are free to depart from the membrane and dissolve in the surrounding solution. 
E) They have hydrophilic tails in the interior of the membrane. 
A) They can move laterally along the plane of the membrane. 
B) They frequently flip-flop from one side of the membrane to the other. 
C) They occur in an uninterrupted bilayer, with membrane proteins restricted to the surface of the membrane. 
D) They are free to depart from the membrane and dissolve in the surrounding solution. 
E) They have hydrophilic tails in the interior of the membrane.

Question 5

Celery stalks that are immersed in fresh water for several hours become stiff and hard.Similar stalks left in a 0.15 M 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 6

Proton pumps are used in various ways by members of every domain of organisms: Bacteria,Archaea,and Eukarya.What does this most probably mean?

Accepted Answer

A) Proton pumps must have evolved before any living organisms were present on Earth. 
B) Proton gradients across a membrane were used by cells that were the common ancestor of all three domains of life. 
C) The high concentration of protons in the ancient atmosphere must have necessitated a pump mechanism. 
D) Cells of each domain evolved proton pumps independently when oceans became more acidic. 
E) Proton pumps are necessary to all cell membranes. 
A) Proton pumps must have evolved before any living organisms were present on Earth. 
B) Proton gradients across a membrane were used by cells that were the common ancestor of all three domains of life. 
C) The high concentration of protons in the ancient atmosphere must have necessitated a pump mechanism. 
D) Cells of each domain evolved proton pumps independently when oceans became more acidic. 
E) Proton pumps are necessary to all cell membranes.

Question 7

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 cotransport 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 cotransport of glucose and hydrogen 
E) by using active transport

Question 8

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 9

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 10

-Which of the following correctly describes the function of the sodium-potassium pump?

Accepted Answer

A) moves three potassium ions out of a cell and two sodium ions into a cell while producing an ATP in each cycle 
B) moves three sodium ions out of a cell and two potassium ions into a cell while consuming an ATP in each cycle 
C) moves three potassium ions out of a cell and two sodium ions into a cell while consuming 2 ATP in each cycle 
D) moves three sodium ions out of a cell and two potassium ions into a cell and while producing an ATP in each cycle 
E) moves three sodium ions out of a cell and three potassium ions into a cell and producing an ATP in each cycle 
A) moves three potassium ions out of a cell and two sodium ions into a cell while producing an ATP in each cycle 
B) moves three sodium ions out of a cell and two potassium ions into a cell while consuming an ATP in each cycle 
C) moves three potassium ions out of a cell and two sodium ions into a cell while consuming 2 ATP in each cycle 
D) moves three sodium ions out of a cell and two potassium ions into a cell and while producing an ATP in each cycle 
E) moves three sodium ions out of a cell and three potassium ions into a cell and producing an ATP in each cycle

Question 11

A protein that spans the phospholipid bilayer one or more times is

Accepted Answer

A) a transmembrane protein. 
B) an integral protein. 
C) a peripheral protein. 
D) an integrin. 
E) a glycoprotein. 
A) a transmembrane protein. 
B) an integral protein. 
C) a peripheral protein. 
D) an integrin. 
E) a glycoprotein.

Question 12

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 13

Which of the following is most likely true of a protein that cotransports glucose and sodium ions into the intestinal cells of an animal?

Accepted Answer

A) The sodium ions are moving down their electrochemical gradient while glucose is moving up. 
B) Glucose entering the cell along its concentration gradient provides energy for uptake of sodium ions against the electrochemical gradient. 
C) Sodium ions can move down their electrochemical gradient through the cotransporter whether or not glucose is present outside the cell. 
D) The cotransporter can also transport potassium ions. 
E) A substance that blocks sodium ions from binding to the cotransport protein will also block the transport of glucose. 
A) The sodium ions are moving down their electrochemical gradient while glucose is moving up. 
B) Glucose entering the cell along its concentration gradient provides energy for uptake of sodium ions against the electrochemical gradient. 
C) Sodium ions can move down their electrochemical gradient through the cotransporter whether or not glucose is present outside the cell. 
D) The cotransporter can also transport potassium ions. 
E) A substance that blocks sodium ions from binding to the cotransport protein will also block the transport of glucose.

Question 14

Which of the following processes requires energy?

Accepted Answer

A) diffusion 
B) facilitated diffusion 
C) transport through channels 
D) osmosis 
E) pinocytosis 
A) diffusion 
B) facilitated diffusion 
C) transport through channels 
D) osmosis 
E) pinocytosis

Question 15

Three lab groups carried out an experiment to identify the correct molarities for five solutions.Each unknown contained one of the following sucrose concentrations: 0.0 M,0.2 M,0.4 M,0.6 M,0.8 M,and 1.0 M.Each data entry represents the average of 3 sample replications of 1 cm3 sweet potato cubes expressed as percent change in mass after an overnight (24 hr)soak in the unknown solutions.From the data given,which statement most accurately describes what is occurring in response to a particular unknown solution.

Accepted Answer

A) Unknown solution E contains the highest concentration of sucrose and the change in mass is due to the active transport of sucrose into the cell in exchange for water molecules. 
B) Osmosis of water molecules from unknown solution A likely caused the increase in mass observed. 
C) Passive transport of sucrose out of the potato cells explains the change in mass observed for unknown solution F. 
D) Unknown solution C represents a sucrose molarity slightly lower than the molarity of sweet potato cells, thus water is transported out of the cells. 
E) Transport of Na+ to the outside of the cell is likely have caused the decrease in mass observed for unknown solution C. 
A) Unknown solution E contains the highest concentration of sucrose and the change in mass is due to the active transport of sucrose into the cell in exchange for water molecules. 
B) Osmosis of water molecules from unknown solution A likely caused the increase in mass observed. 
C) Passive transport of sucrose out of the potato cells explains the change in mass observed for unknown solution F. 
D) Unknown solution C represents a sucrose molarity slightly lower than the molarity of sweet potato cells, thus water is transported out of the cells. 
E) Transport of Na+ to the outside of the cell is likely have caused the decrease in mass observed for unknown solution C.

Question 16

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 17

What is the voltage across a membrane called?

Accepted Answer

A) water potential 
B) chemical gradient 
C) membrane potential 
D) osmotic potential 
E) electrochemical gradient 
A) water potential 
B) chemical gradient 
C) membrane potential 
D) osmotic potential 
E) electrochemical gradient

Question 18

The difference between pinocytosis and receptor-mediated endocytosis is that

Accepted Answer

A) pinocytosis brings only water molecules 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 molecules 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 19

When a plant cell,such as one from a peony stem,is submerged in a very hypotonic solution,what is likely to occur?

Accepted Answer

A) The cell will burst. 
B) The cell membrane will lyse. 
C) Plasmolysis will shrink the interior. 
D) The cell will become flaccid. 
E) The cell will become turgid. 
A) The cell will burst. 
B) The cell membrane will lyse. 
C) Plasmolysis will shrink the interior. 
D) The cell will become flaccid. 
E) The cell will become turgid.

Question 20

For the following questions,match the labelled component of the cell membrane in the figure with its description.
  
-Which component is a glycolipid?

Accepted Answer

A) A 
B) B 
C) C 
D) D 
E) E 
A) A 
B) B 
C) C 
D) D 
E) E

Exam 7: Membrane Structure and Function

Nitrous oxide gas molecules diffusing across a cell's plasma membrane is an example of

For the following questions,match the labelled component of the cell membrane in the figure with its description. -Which component is a microfilament of the cytoskeleton?

According to the fluid mosaic model of cell membranes,which of the following is a true statement about membrane phospholipids?

Celery stalks that are immersed in fresh water for several hours become stiff and hard.Similar stalks left in a 0.15 M salt solution become limp and soft.From this we can deduce that the cells of the celery stalks are

Proton pumps are used in various ways by members of every domain of organisms: Bacteria,Archaea,and Eukarya.What does this most probably mean?

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?

The presence of cholesterol in the plasma membranes of some animals

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 correctly describes the function of the sodium-potassium pump?

A protein that spans the phospholipid bilayer one or more times is

Which of the following statements is correct about diffusion?

Which of the following is most likely true of a protein that cotransports glucose and sodium ions into the intestinal cells of an animal?

Which of the following processes requires energy?

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

What is the voltage across a membrane called?

The difference between pinocytosis and receptor-mediated endocytosis is that

When a plant cell,such as one from a peony stem,is submerged in a very hypotonic solution,what is likely to occur?

For the following questions,match the labelled component of the cell membrane in the figure with its description. -Which component is a glycolipid?

Introduction: Evolution and Themes of Biology

The Chemical Context of Life

Water and Life

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 and Fermentation

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

Regulation of Gene Expression

Viruses

DNA Tools and 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 Overview of Animal Diversity

An Introduction to Invertebrates

The Origin and Evolution of Vertebrates

Plant Structure,Growth,and Development

Resource Acquisition and 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 Signalling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behaviour

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems and Restoration Ecology

Conservation Biology and Global Change

Filters