Campbell Biology: Concepts and Connections, 8e (Reece et al.)
Chapter 5 The Working Cell
5.1 Multiple-Choice Questions
1) Many physiological conditions are related to particular proteins in cell membranes. The
number of insulin receptors in membranes is related to the amount of insulin present around
those cells. If the presence of increased insulin results in a decrease in receptors and a decrease in
insulin results in an increase in insulin receptors, this would be an example of
A) a metabolic pathway.
B) negative or regulatory feedback.
C) passive transport.
D) competitive inhibition.
2) The fluid mosaic model describes the plasma membrane as consisting of
A) a phospholipid bilayer with embedded carbohydrates.
B) two layers of phospholipids with cholesterol sandwiched between them.
C) carbohydrates and phospholipids that can drift in the membrane.
D) diverse proteins embedded in a phospholipid bilayer.
3) Membrane phospholipids
A) have hydrophobic heads that face the center of the membrane and are shielded from water.
B) have hydrophilic tails that face outward and are exposed to water.
C) are able to drift about in the plasma membrane.
D) remain fluid because they are tightly packed against one another.
4) The cholesterol associated with animal cell membranes
A) is attached to membrane proteins and extends into the watery environment surrounding the
cell.
B) helps to keep phospholipids from being too close to one another.
C) is an abnormality resulting from a diet high in cholesterol.
D) helps solidify the membranes when the room temperature is below freezing.
5) If you were working for a pharmaceutical company as part of a drug discovery team, which of
these enzyme inhibitors would you suggest as a productive avenue for drug development?
A) a drug to treat high blood pressure that reversibly inhibits an enzyme catalyzing production of
a chemical that causes blood vessels to contract
B) a drug to treat diabetes that irreversibly inhibits an enzyme in the metabolic pathway to
synthesize glucose
C) a compound that acts as a competitive inhibitor for a digestive enzyme produced only in the
presence of certain foods
D) a compound that inhibits enzymes by significantly changing the pH throughout the body
6) Aspirin and other nonsteroidal anti-inflammatory drugs (NSAID)inhibit inflammation by
inhibiting an enzyme in the prostaglandin pathway, but by inhibiting this enzyme and this
pathway they also inhibit pathways that protect the stomach from damage by stomach acid and
that prevent aggregation of blood platelets to form blood clots. What can you conclude from
this?
A) The enzyme inhibition is nonreversible.
B) The enzyme is found in many different types of cells.
C) Prostaglandins cause blood clotting.
D) Aspirin should not be given to people who people who need to synthesize enzymes.
7) Most of the functions of a cell membrane, including transport and enzymatic function, are
performed by
A) glycolipids.
B) proteins.
C) phospholipids.
D) cholesterol.
8) Which of the following statements regarding membrane protein function is false?
A) Membrane proteins serve as enzymes.
B) Membrane proteins act as receptors to molecules like hormones.
C) Membrane proteins form junctions between cells.
D) Membrane proteins transfer genetic information to the cytoplasm.
9) Relaying a message from a membrane receptor to a molecule that performs a specific function
within a cell occurs when
A) a signaling molecule binds to a protein that extends to the outside of the cell.
B) a protein receptor on the interior of the membrane become bounds by a signaling molecule.
C) the extracellular matrix is moved to the inside of the cell.
D) glycoproteins are recognized by other cells.
10) Plasma membranes are selectively permeable. This means that
A) anything can pass into or out of a cell as long as the membrane is intact and the cell is
healthy.
B) the plasma membrane allows some substances to enter or leave a cell more easily than others.
C) glucose cannot enter the cell.
D) plasma membranes must be very thick.
11) Which of the following statements regarding membrane function is false?
A) The plasma membrane forms a selective barrier around the cell.
B) The plasma membrane plays a role in transferring signals to the cell’s interior.
C) The plasma membrane has receptors for chemical messages.
D) The plasma membrane is the control center of the cell.
12) Which characteristic promoted the utilization of lipids as the first cell membrane?
A) spontaneous degradation of the intracellular environment
B) self-assembly into a simple membrane
C) ability to form an impermeable membrane
D) formation of a semi-solid membrane
13) All cells are enclosed by a plasma membrane that is similar in ________ and ________.
A) thickness; composition
B) permeability; content
C) lucidity; texture
D) structure; function
14) Small, nonpolar, hydrophobic molecules such as fatty acids
A) easily pass through a membrane’s lipid bilayer.
B) very slowly diffuse through a membrane’s lipid bilayer.
C) require transport proteins to pass through a membrane’s lipid bilayer.
D) are actively transported across cell membranes.
15) Which of the following substances would have the most trouble crossing a biological
membrane by diffusing through the lipid bilayer?
A) O2
B) CO2
C) Na+
D) a small, nonpolar molecule such as butane (C4H10)
16) Oxygen crosses a plasma membrane by
A) osmosis.
B) active transport.
C) pinocytosis.
D) passive transport.
17) Which of the following statements regarding diffusion is false?
A) Diffusion is a result of the thermal energy of atoms and molecules.
B) Diffusion requires no input of energy into the system.
C) Diffusion occurs when particles spread from areas where they are less concentrated to areas
where they are more concentrated.
D) Diffusion occurs even after equilibrium is reached and no net change is apparent.
18) Diffusion does not require the cell to expend ATP. Therefore, diffusion is considered a type
of
A) exocytosis.
B) passive transport.
C) active transport.
D) endocytosis.
19) Osmosis can be defined as
A) the diffusion of water.
B) the diffusion of nonpolar molecules.
C) active transport.
D) the diffusion of a solute.
20) When two aqueous solutions that differ in solute concentration are placed on either side of a
semipermeable membrane and osmosis is allowed to take place, the water will
A) exhibit a net movement to the side with lower free water concentration.
B) exhibit a net movement to the side with higher free water concentration.
C) exhibit a net movement to the side with lower solute concentration.
D) exhibit an equal movement in both directions across the membrane.
21) In the lab, you use a special balloon that is permeable to water but not sucrose to make an
“artificial cell.” The balloon is filled with a solution of 20% sucrose and 80% water and is
immersed in a beaker containing a solution of 40% sucrose and 60% water. Which of the
following will occur?
A) Water will leave the balloon.
B) Water will enter the balloon.
C) Sucrose will leave the balloon.
D) Sucrose will enter the balloon.
22) Some protozoans have special organelles called contractile vacuoles that continually
eliminate excess water from the cell. The presence of these organelles tells you that the
environment
A) is isotonic to the protozoan.
B) is hypotonic to the protozoan.
C) contains a higher concentration of solutes than the protozoan.
D) is hypertonic to the protozoan.
23) A cell that has neither a net gain of water nor net loss of water when it is immersed in a
solution must be
A) isotonic to its environment.
B) hypertonic to its environment.
C) hypotonic to its environment.
D) metabolically inactive.
24) In a hypotonic solution, an animal cell will
A) lyse.
B) experience turgor.
C) neither gain nor lose water.
D) shrivel.
25) If placed in tap water, an animal cell will undergo lysis, whereas a plant cell will not. What
accounts for this difference?
A) the expulsion of water by the plant cell’s central vacuole
B) the relative impermeability of the plant cell wall to water
C) the fact that plant cells are isotonic to tap water
D) the relative inelasticity and strength of the plant cell wall
26) In the lab, you use a special balloon that is permeable to water but not sucrose to make an
“artificial cell.” The balloon is filled with a solution of 20% sucrose and 80% water and is
immersed in a beaker containing a solution of 40% sucrose and 60% water. The solution in the
balloon is ________ relative to the solution in the beaker.
A) isotonic
B) hypotonic
C) hypertonic
D) hydrophilic
27) White blood cells (WBCs) are more resistant to lysis than red blood cells (RBCs). When
looking at a sample of blood for WBCs, what could you do to reduce interference from RBCs?
A) Mix the blood in a salty solution to cause the RBCs to lyse.
B) Mix the blood in an isotonic solution and allow the WBCs to float to the top.
C) Mix the blood in a hypotonic solution, which will cause the RBCs to lyse.
D) Mix the blood in a hypertonic solution, which will cause the RBCs to lyse.
28) A plant cell in a hypotonic solution
A) becomes turgid because of an inflow of water.
B) bursts because of an inflow of water.
C) shrivels because of an outflow of water.
D) wilts because of an outflow of water.
29) You are adrift in the Atlantic Ocean and, being thirsty, drink the surrounding seawater. As a
result,
A) you quench your thirst.
B) your cells become turgid.
C) you dehydrate yourself.
D) your cells lyse from excessive water intake.
30) Facilitated diffusion across a biological membrane requires ________ and moves a substance
________ its concentration gradient.
A) energy and transport proteins; down
B) transport proteins; down
C) energy and transport proteins; against
D) transport proteins; against
31) The molecules responsible for membrane transport are
A) steroids.
B) phospholipids.
C) carbohydrates.
D) proteins.
32) Which of the following statements is true for all types of passive transport?
A) Proteins are needed to transport molecules across the membrane.
B) The concentration gradient is the driving force.
C) Only small polar molecules are able to cross the plasma membrane.
D) Ions never cross the plasma membrane by passive transport.
33) Aquaporins
A) allow water to cross the plasma membrane via facilitated diffusion.
B) allow water to cross the plasma membrane against its concentration gradient.
C) allow for the active transport of water.
D) are found in all cells.
34) Which of the following processes can move a solute against its concentration gradient?
A) osmosis
B) passive transport
C) facilitated diffusion
D) active transport
35) Which of the following is a typical feature of an ATP-driven active transport mechanism?
A) The transport protein must cross to the correct side of the membrane before the solute can
bind to it.
B) The transport protein is irreversibly phosphorylated as transport takes place.
C) The transport protein catalyzes the conversion of ADP to ATP.
D) The solute moves against the concentration gradient.
36) Which of the following statements regarding active transport is false?
A) Active transport uses ATP as an energy source.
B) Active transport can move a solute against its concentration gradient.
C) Active transport requires the cell to expend energy.
D) Active transport is driven by the concentration gradient.
37) Certain cells that line the stomach synthesize a digestive enzyme and secrete it into the
stomach. This enzyme is a protein. Which of the following processes could be responsible for its
secretion?
A) endocytosis
B) exocytosis
C) diffusion
D) pinocytosis
38) The process of a white blood cell engulfing a bacterium is
A) osmosis.
B) receptor-mediated endocytosis.
C) pinocytosis.
D) phagocytosis.
39) Phagocytosis is to eating as pinocytosis is to
A) osmosis.
B) drinking.
C) chewing.
D) lysis.
40) Cells acquire low-density lipoproteins (LDLs) by
A) diffusion.
B) receptor-mediated endocytosis.
C) pinocytosis.
D) phagocytosis.
41) Kinetic energy differs from chemical energy in that
A) kinetic energy is stored energy that has the potential to do work, and chemical energy is the
energy of movement.
B) kinetic energy can be converted into various forms of energy, whereas chemical energy can
only be converted into heat.
C) kinetic energy is the energy of a moving object, whereas chemical energy is the potential
energy of molecules.
D) chemical energy is a particular form of kinetic energy.
42) Glucose molecules provide energy to power the swimming motion of sperm. In this example,
the sperm are changing
A) chemical energy into kinetic energy.
B) chemical energy into potential energy.
C) kinetic energy into potential energy.
D) kinetic energy into thermal energy.
43) In the reaction A → B + C + heat,
A) there is a net input of energy.
B) the potential energy of the products is greater than that of the reactant.
C) the potential energy of the products is less than that of the reactant.
D) entropy has decreased.
44) Which of the following statements regarding thermodynamics is false?
A) Thermodynamics is the study of energy transformations that occur in a collection of matter.
B) A single cell or the planet Earth could be a thermodynamic system.
C) An open system exchanges both energy and matter with its surroundings.
D) An automobile engine is a closed system because it does not exchange energy and matter with
its surroundings.
45) According to ________, energy cannot be created or destroyed.
A) Aristotle’s first principle
B) the first law of thermodynamics
C) the second law of thermodynamics
D) the third law of thermodynamics
46) A steer must eat at least 100 pounds of grain to gain less than 10 pounds of muscle tissue.
This illustrates
A) the first law of thermodynamics.
B) the second law of thermodynamics.
C) that some energy is destroyed in every energy conversion.
D) that energy transformations are typically 100% efficient.
47) Which of the following direct energy transfers is impossible in living systems?
A) light energy to chemical energy
B) chemical energy to kinetic energy
C) light energy to potential energy
D) heat to light energy
48) Living systems
A) violate the first law of thermodynamics.
B) violate the second law of thermodynamics.
C) decrease their entropy while increasing the entropy of the universe.
D) are examples of a closed system.
49) Which of the following processes is endergonic?
A) the burning of wood
B) the synthesis of glucose from carbon dioxide and water
C) the breakdown of glucose
D) cellular respiration
50) What is the basic difference between exergonic and endergonic reactions?
A) Exergonic reactions involve ionic bonds; endergonic reactions involve covalent bonds.
B) Exergonic reactions involve the breaking of bonds; endergonic reactions involve the
formation of bonds.
C) Exergonic reactions release energy; endergonic reactions absorb it.
D) In exergonic reactions, the reactants have less chemical energy than the products; in
endergonic reactions, the opposite is true.