Question 1

What will happen to a red blood cell rbc), which has an internal ion concentration of about 0.9 percent, if it is placed into a beaker of pure water?

Accepted Answer

A)  The cell would shrink because the water in the beaker is hypertonic relative to the cytoplasm of the rbc. 
B)  The cell would shrink because the water in the beaker is hypotonic relative to the cytoplasm of the rbc. 
C)  The cell would swell because the water in the beaker is hypotonic relative to the cytoplasm of the rbc. 
D)  Nothing. 
A)  The cell would shrink because the water in the beaker is hypertonic relative to the cytoplasm of the rbc. 
B)  The cell would shrink because the water in the beaker is hypotonic relative to the cytoplasm of the rbc. 
C)  The cell would swell because the water in the beaker is hypotonic relative to the cytoplasm of the rbc. 
D)  Nothing. C

Question 2

Which aspect of phospholipids is most important to the formation of bilayers?

Accepted Answer

A)  Their size is small, relative to fats. 
B)  They are amphipathic. 
C)  Their size is large, relative to cholesterol. 
D)  Their hydrocarbon tails can consist of fatty acids or isoprene subunits. 
A)  Their size is small, relative to fats. 
B)  They are amphipathic. 
C)  Their size is large, relative to cholesterol. 
D)  Their hydrocarbon tails can consist of fatty acids or isoprene subunits. B

Question 3

You make two sucrose solutions, one of 0.5M and one of 2M and go out for lunch. When you return, you realize that you forgot to label the beakers! You remake the solutions, but give the undergrads in your lab an experiment to determine which beaker holds which solution. They fill two balloons, which are semi- permeable to water, but not to sucrose, with a 0.75M sucrose solution. One balloon is then placed in each of the unknown sucrose solution beakers. After several hours, they observe that the balloon in beaker 1 has swelled, while the balloon in beaker 2 has shrivelled. This indicates that beaker one contained the _ sucrose solution, while beaker 2 contained the sucrose solution.

Accepted Answer

A)  0.5M; 2M 
B)  2M; 0.5M 
C)  unable to determine given the information provided. 
A)  0.5M; 2M 
B)  2M; 0.5M 
C)  unable to determine given the information provided. A

Question 4

What most distinguishes lipids from other biomolecules is

Accepted Answer

A)  that only lipids contain hydrogen atoms. 
B)  their chemical properties. 
C)  their molecular weight size). 
D)  where they are found in the body. 
A)  that only lipids contain hydrogen atoms. 
B)  their chemical properties. 
C)  their molecular weight size). 
D)  where they are found in the body.

Question 5

You have a planar bilayer at a relatively warm temperature. After testing the permeability of this membrane to glucose, you increase the quantity of cholesterol in the bilayer. What will happen?

Accepted Answer

A)  You can't predict the outcome. You simply have to make the measurement. 
B)  Permeability to glucose will stay the same. 
C)  Permeability to glucose will increase. 
D)  Permeability to glucose will decrease. 
A)  You can't predict the outcome. You simply have to make the measurement. 
B)  Permeability to glucose will stay the same. 
C)  Permeability to glucose will increase. 
D)  Permeability to glucose will decrease.

Question 6

You make two sucrose solutions, one 0.5M and one of 2M and go out for lunch. When you return, you realize that you forgot to label the beakers! You remake the solutions, but give the undergrads in your lab an experiment to determine which beaker holds which solution. They fill two balloons, which are semi- permeable to water, but not to sucrose, with a 0.75M sucrose solution. One balloon is then placed in each of the unknown sucrose solution beakers. After several hours, they observe that the balloon in beaker 1 has swelled, while the balloon in beaker 2 has shriveled. This indicates that the solution in beaker 1 was relative to the solution in the balloon, while beaker 2's solution was relative to the solution in the balloon.

Accepted Answer

A)  hypotonic, isotonic 
B)  hypertonic, hypotonic 
C)  hypotonic, hypertonic 
D)  hypertonic, isotonic 
A)  hypotonic, isotonic 
B)  hypertonic, hypotonic 
C)  hypotonic, hypertonic 
D)  hypertonic, isotonic

Question 7

The cell membrane is often referred to as asymmetrical or "mosaic". This means that

Accepted Answer

A)  the phospholipids of the membrane can flip- flop such that phospholipids from the inner layer are exchanged with those from the outer layer. 
B)  only certain substances can pass through the phospholipid bilayer freely, while others require the help of membrane proteins. 
C)  both layers of the phospholipid bilayer are not identical in terms of protein type or number and phospholipid type. 
A)  the phospholipids of the membrane can flip- flop such that phospholipids from the inner layer are exchanged with those from the outer layer. 
B)  only certain substances can pass through the phospholipid bilayer freely, while others require the help of membrane proteins. 
C)  both layers of the phospholipid bilayer are not identical in terms of protein type or number and phospholipid type.

Question 8

Cooking oil and gasoline a hydrocarbon) are not amphipathic molecules. Why?

Accepted Answer

A)  They do not have a hydrophobic region. 
B)  They do not have a polar or charged region. 
C)  They spontaneously form micelles or liposomes in solution. 
D)  They are highly reduced molecules. 
A)  They do not have a hydrophobic region. 
B)  They do not have a polar or charged region. 
C)  They spontaneously form micelles or liposomes in solution. 
D)  They are highly reduced molecules.

Question 9

Based on the figure provided, which of the following experimental treatments would increase the rate of sucrose transport into the cell?

Accepted Answer

A)  adding a substance that makes the membrane more permeable to hydrogen ions 
B)  decreasing extracellular sucrose concentration 
C)  decreasing cytoplasmic pH 
D)  adding an inhibitor that blocks the regeneration of ATP 
E)  decreasing extracellular pH 
A)  adding a substance that makes the membrane more permeable to hydrogen ions 
B)  decreasing extracellular sucrose concentration 
C)  decreasing cytoplasmic pH 
D)  adding an inhibitor that blocks the regeneration of ATP 
E)  decreasing extracellular pH

Question 10

Cystic fibrosis CF) is a membrane- transport disease that is caused by an allele found primarily in Caucasian populations. What mechanism fails in CF patients?

Accepted Answer

A)  production of ATP 
B)  movement of sodium and potassium across cell membranes 
C)  phospholipids in the cell membrane that are not formed properly 
D)  movement of chloride ions across cell membranes 
A)  production of ATP 
B)  movement of sodium and potassium across cell membranes 
C)  phospholipids in the cell membrane that are not formed properly 
D)  movement of chloride ions across cell membranes

Question 11

If you mechanically shook a mixture of amphipathic lipids and water, what would you expect to see when the solution is observed with an electron microscope?

Accepted Answer

A)  The lipids will have formed planar bilayer membranes. 
B)  The lipids will have formed tiny vesicles filled with water. 
C)  The lipids will have completely dissolved in the solution because they are partially polar. 
D)  The lipids and water will have separated into two distinct layers because the lipids are partially nonpolar. 
A)  The lipids will have formed planar bilayer membranes. 
B)  The lipids will have formed tiny vesicles filled with water. 
C)  The lipids will have completely dissolved in the solution because they are partially polar. 
D)  The lipids and water will have separated into two distinct layers because the lipids are partially nonpolar.

Question 12

You want to view the surface of a particular cell or tissue group of related cells) at magnifications above 1000x. What tool would you use?

Accepted Answer

A)  confocal microscope 
B)  light microscope 
C)  transmission electron microscope 
D)  scanning electron microscope 
A)  confocal microscope 
B)  light microscope 
C)  transmission electron microscope 
D)  scanning electron microscope

Question 13

Which of the following phospholipid membranes would be most permeable to glycerol?

Accepted Answer

A)  one with long and unsaturated tails 
B)  one with short and saturated tails 
C)  one with long and saturated fatty- acid tails 
D)  one with short and unsaturated tails 
A)  one with long and unsaturated tails 
B)  one with short and saturated tails 
C)  one with long and saturated fatty- acid tails 
D)  one with short and unsaturated tails

Question 14

Which of the following means of transport would most likely be used for moving a medium- sized molecule like a monosaccharide or an amino acid) from a low concentration on the outside of a cell to a high concentration on the inside of a cell?

Accepted Answer

A)  active transport through a "pump" protein 
B)  facilitated diffusion through an ion channel protein 
C)  facilitated diffusion through a transporter protein 
D)  passive transport 
A)  active transport through a "pump" protein 
B)  facilitated diffusion through an ion channel protein 
C)  facilitated diffusion through a transporter protein 
D)  passive transport

Question 15

Integral membrane proteins stay in membranes because of

Accepted Answer

A)  the locations of their polar and nonpolar amino acids. 
B)  their small size, which does not allow them to pass through the membrane. 
C)  osmotic pressure from proteins outside the cell. 
D)  diffusion of proteins from the cytoplasm to the membrane. 
A)  the locations of their polar and nonpolar amino acids. 
B)  their small size, which does not allow them to pass through the membrane. 
C)  osmotic pressure from proteins outside the cell. 
D)  diffusion of proteins from the cytoplasm to the membrane.

Question 16

Under what circumstances does membrane transport always require energy?

Accepted Answer

A)  whenever a molecule is polar and is moved through a phospholipid bilayer membrane 
B)  whenever a solute needs to be moved from low concentration to high concentration through a phospholipid bilayer membrane 
C)  whenever a solute is charged, such as an ion, and is moved through a phospholipid bilayer membrane 
D)  whenever molecules are moved that are too large to pass through the phospholipid bilayer membrane 
A)  whenever a molecule is polar and is moved through a phospholipid bilayer membrane 
B)  whenever a solute needs to be moved from low concentration to high concentration through a phospholipid bilayer membrane 
C)  whenever a solute is charged, such as an ion, and is moved through a phospholipid bilayer membrane 
D)  whenever molecules are moved that are too large to pass through the phospholipid bilayer membrane

Question 17

In marshes and other wet areas where vegetation is rotting, the water surface often has an oily sheen due to insoluble compounds. What are these molecules?

Accepted Answer

A)  carbohydrates 
B)  lipids 
C)  nucleic acids 
D)  proteins 
A)  carbohydrates 
B)  lipids 
C)  nucleic acids 
D)  proteins

Question 18

Which of the following crosses lipid bilayers the fastest?

Accepted Answer

A)  a large, polar molecule like glucose 
B)  a small, nonpolar molecule like oxygen O2) 
C)  a sodium ion 
D)  a small, polar molecule like water 
A)  a large, polar molecule like glucose 
B)  a small, nonpolar molecule like oxygen O2) 
C)  a sodium ion 
D)  a small, polar molecule like water

Question 19

Sodium- potassium pumps

Accepted Answer

A)  use ATP molecules to move protons to the inner side of cell membranes. 
B)  move three potassium ions and two sodium ions while producing an ATP for each cycle. 
C)  produce ATP for cells while making the outside of cell membranes negatively charged. 
D)  move two potassium ions and three sodium ions while consuming an ATP for each cycle. 
A)  use ATP molecules to move protons to the inner side of cell membranes. 
B)  move three potassium ions and two sodium ions while producing an ATP for each cycle. 
C)  produce ATP for cells while making the outside of cell membranes negatively charged. 
D)  move two potassium ions and three sodium ions while consuming an ATP for each cycle.

Question 20

Where would you most likely find an integral membrane protein?

Accepted Answer

A)  floating freely in the cytoplasm 
B)  on the inside surface of the cell membrane 
C)  on the outside surface of the cell membrane 
D)  spanning the cell membrane, with parts of the protein visible from both the inside and the outside of the cell 
A)  floating freely in the cytoplasm 
B)  on the inside surface of the cell membrane 
C)  on the outside surface of the cell membrane 
D)  spanning the cell membrane, with parts of the protein visible from both the inside and the outside of the cell

Exam 6: Lipids, Membranes, and the First Cells

What will happen to a red blood cell rbc), which has an internal ion concentration of about 0.9 percent, if it is placed into a beaker of pure water?

Which aspect of phospholipids is most important to the formation of bilayers?

What most distinguishes lipids from other biomolecules is

You have a planar bilayer at a relatively warm temperature. After testing the permeability of this membrane to glucose, you increase the quantity of cholesterol in the bilayer. What will happen?

The cell membrane is often referred to as asymmetrical or "mosaic". This means that

Cooking oil and gasoline a hydrocarbon) are not amphipathic molecules. Why?

Based on the figure provided, which of the following experimental treatments would increase the rate of sucrose transport into the cell?

Cystic fibrosis CF) is a membrane- transport disease that is caused by an allele found primarily in Caucasian populations. What mechanism fails in CF patients?

If you mechanically shook a mixture of amphipathic lipids and water, what would you expect to see when the solution is observed with an electron microscope?

You want to view the surface of a particular cell or tissue group of related cells) at magnifications above 1000x. What tool would you use?

Which of the following phospholipid membranes would be most permeable to glycerol?

Which of the following means of transport would most likely be used for moving a medium- sized molecule like a monosaccharide or an amino acid) from a low concentration on the outside of a cell to a high concentration on the inside of a cell?

Integral membrane proteins stay in membranes because of

Under what circumstances does membrane transport always require energy?

In marshes and other wet areas where vegetation is rotting, the water surface often has an oily sheen due to insoluble compounds. What are these molecules?

Which of the following crosses lipid bilayers the fastest?

Sodium- potassium pumps

Where would you most likely find an integral membrane protein?

Biology and the Tree of Life

Water and Carbon: the Chemical Basis of Life

Protein Structure and Function

Nucleic Acids and the Rna World

An Introduction to Carbohydrates

Inside the Cell

Energy and Enzymes

Cellular Respiration and Fermentation

Photosynthesis

Cellcell Interactions

The Cell Cycle

Meiosis

Mendel and the Gene

Dna and the Gene: Synthesis and Repair

How Genes Work

Transcription, Rna Processing, and Translation

Control of Gene Expression in Bacteria

Control of Gene Expression in Eukaryotes

The Molecular Revolution: Biotechnology and Beyond

Gene Structure and Development

Evolution by Natural Selection

Evolutionary Processes

Speciation

Phylogenies and the History of Life

Bacteria and Archaea

Protists

Green Algae and Land Plants

Fungi

An Introduction to Animals

Protostome Animals

Deuterostome Animals

Viruses

Plant Form and Function

Water and Sugar Transport in Plants

Plant Nutrition

Plant Sensory Systems, Signals, and Responses

Plant Reproduction and Development

Animal Form and Function

Water and Electrolyte Balance in Animals

Animal Nutrition

Gas Exchange and Circulation

Animal Nervous Systems

Animal Sensory Systems

Animal Movement

Chemical Signals in Animals

Animal Reproduction and Development

The Immune System in Animals

An Introduction to Ecology

Behavioural Ecology

Population Ecology

Community Ecology

Ecosystems and Global Ecology

Biodiversity and Conservation Biology

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