Biology: A Guide to the Natural World, 5e (Krogh)
Chapter 5 Life’s Border: The Plasma Membrane
1) The outer living limit of the cell is called the:
A) cell wall.
B) edge.
C) plastid.
D) plasma membrane.
2) Cystic fibrosis is the result of:
A) no sodium channel protein.
B) no sodium-potassium pump.
C) an abnormal sodium channel protein.
D) an abnormal chloride channel protein.
E) cysts in the lungs.
3) The primary component of the plasma membrane is:
A) cholesterol.
B) phospholipid.
C) protein.
D) carbohydrate.
4) A purpose of the plasma membrane is to:
A) form the outer boundary of a cell.
B) produce proteins.
C) allow no contact with other cells.
D) keep harmful substances within the cell.
E) form ribosomes.
5) Which of the following is an accurate description of the plasma membrane?
A) It is a phospholipid bilayer embedded with proteins.
B) It separates the nuclear contents from the environment.
C) It is permeable to all substances.
D) It is a solid material.
6) Short chains of sugars attached to proteins or phospholipids in the cell membrane make up
the:
A) phospholipid bilayer.
B) communication proteins.
C) cholesterol.
D) glycocalyx.
7) The ________ of a phospholipid molecule will seek water, whereas the ________ of the
molecules will avoid water.
A) tail; head
B) head; tail
C) hydrophobic portion; hydrophilic portion
D) fatty acid; phosphate group
8) The huge array of capabilities of the plasma membrane are performed by its:
A) carbohydrates.
B) proteins.
C) phospholipids.
D) cholesterol.
9) Which of the following is true of the plasma membrane?
A) It controls the passage of substances into and out of the cell.
B) It only allows hydrophilic materials to pass through.
C) It is a rigid, nonchanging structure.
D) Its capabilities are primarily determined by carbohydrates in the membrane.
10) How does glucose enter a cell if levels of blood glucose are high?
A) An electrical signal is passed through the blood, opening glucose channels within the
membranes of cells.
B) Insulin molecules bind to glucose receptors, causing cellular responses to take up glucose.
C) The glucose molecules diffuse through the membrane.
D) Glucose pokes a hole in the cell’s membrane, creating a channel through which it can move.
11) The phospholipids of membranes are:
A) hydrophilic molecules.
B) hydrophobic molecules.
C) both hydrophilic and hydrophobic molecules.
D) oils.
12) The fatty-acid tails of a phospholipid are:
A) hydrophilic.
B) proteins.
C) polar.
D) hydrophobic.
E) carbohydrates.
13) Small, nonpolar molecules easily pass through the phospholipid bilayer because the
molecules:
A) can dissolve in the hydrophobic portion of the bilayer.
B) are brought in by attaching to structural proteins in the membrane.
C) are brought in by attaching to cholesterol in the membrane.
D) dissolve in water and follow the water as it flows into the cell.
14) What is the role of transport proteins within the plasma membrane?
A) Transport proteins prevent the passage of amino acids through the membrane.
B) Transport proteins allow movement of ions and polar molecules through the plasma
membrane.
C) Transport proteins identify the cell.
D) Transport proteins interact with the cytoskeleton to stabilize various parts of the cell.
E) Transport proteins maintain membrane fluidity.
15) A component of the plasma membrane that helps to maintain its fluidity is:
A) protein.
B) carbohydrate.
C) nucleic acid.
D) the phospholipid bilayer.
E) cholesterol.
16) Which statement below is true?
A) All internal cell membranes are similar in structure to the plasma membrane.
B) The only internal membrane of a cell that is similar to the plasma membrane is the nuclear
membrane.
C) All internal membranes of a cell are just giant invaginations from the plasma membrane.
D) Vesicle membranes degrade as they fuse with the plasma membrane during exocytosis.
17) The plasma membrane is composed of phospholipids, which are free to move laterally, and is
peppered with both stationary and mobile proteins. This view of the plasma membrane is known
as the:
A) peppered membrane model.
B) phospholipid bilayer model.
C) fluid-mosaic model.
D) semipermeable membrane model.
18) A main function of the carbohydrates that form the glycocalyx is to:
A) move large molecules in and out of the cell.
B) regulate water movement into the cell.
C) bind cell membranes to the cytoskeleton.
D) act as binding sites for signaling molecules.
E) maintain the proper fluidity of the plasma membrane.
19) Which type of proteins are involved in nutrient transport across the plasma membrane and
why?
A) integral proteins, because they span the membrane and 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 are able to carry nutrients across the
membrane
E) receptor proteins, because their carbohydrate chains bind to nutrients and carry them across
the membrane
20) Membrane proteins perform all of the following functions except:
A) structural support.
B) cell recognition.
C) communication.
D) transport.
E) maintainance of membrane fluidity.
21) You have isolated a cell that is unable to produce cholesterol for its cell membranes. Which
of the following defects is this cell most likely to have?
A) The cell membrane will not have the correct fluidity.
B) The cell will not be able to communicate with other cells.
C) The cell will be unable to transport nutrients.
D) The cell will burst as a result of osmosis.
E) The cell will not be able to regulate the transportation of substances into and out of the cell.
22) If you transferred a phospholipid bilayer from water to oil, what effect would this have on
the membrane?
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 invert its normal structure by positioning the heads on the inside of the
bilayer and the fatty-acid tails outside.
E) The phospholipid bilayer would split into two separate layers, which each would be
maintained in the oil.
23) Peripheral proteins:
A) usually span the entire membrane.
B) have no known functions in membranes.
C) act as channels through which materials can pass.
D) are defective in cystic fibrosis.
E) usually attach to integral proteins.
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24) If you could add a colored label to one phospholipid in the cell’s plasma membrane to
observe this molecule, what kind of movement of the molecule would you see?
A) The molecule would move rapidly back and forth across the surface of the membrane.
B) The molecule would be locked in place by its tightly packed neighbors in the plasma
membrane.
C) The molecule would be converted back and forth between a receptor protein and a
phospholipid.
D) The molecule would move back and forth between the membrane and the surrounding watery
solution.
E) The molecule would flip back and forth from one layer of the membrane to the other.
25) The plasma membrane is a semipermeable membrane. This means that it is:
A) permeable to small molecules except water.
B) permeable to small and uncharged molecules but not to larger or charged substances.
C) only permeable to cholesterol.
D) permeable to large charged molecules but not to small uncharged molecules.
26) Diffusing molecules move ________ until they are ________.
A) down their concentration gradients; evenly distributed
B) up their concentration gradients; evenly distributed
C) through channels of active transport proteins; evenly distributed
D) up their concentration gradients; unevenly distributed
E) down their concentration gradients; unevenly distributed
27) Red blood cells placed in pure water will swell and burst. What process is causing this to
happen?
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) Ions are diffusing across the plasma membrane and destabilizing the phospholipids.
28) The central vacuoles of some plant cells you are studying fill with water and press the cell
contents against their cell walls because of osmosis. What can you predict about the
concentration of solutes in the solution that bathes the turgid plant cells?
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.
29) It seems that bacteria and molds should grow well in jam. It’s extremely high in sugar, a
substance many cells can use for energy, and contains enough other nutrients to support cell
growth. Yet jam can be left unrefrigerated for a very long time without contamination by
microorganisms. How can this be?
A) Bacteria and molds cannot grow on fruit products.
B) The high sugar concentration causes bacterial and mold cells to swell and rupture.
C) The high sugar concentration damages cell membranes.
D) Bacteria and molds cannot get into the jam because its high concentration of sugar makes it
so sticky.
E) The high sugar concentration causes bacterial and mold cells to shrink and die.
30) Oxygen moving through the plasma membrane down its concentration gradient is an
example of:
A) simple diffusion.
B) active transport.
C) facilitated diffusion.
D) osmosis.
31) Which statement about diffusion is correct?
A) Diffusion can occur only through a membrane.
B) Diffusion requires a protein channel.
C) Diffusion of water cannot occur.
D) Diffusion causes movement of materials toward equilibrium.
32) Diffusion is a process by which a substance:
A) goes from lesser to greater concentration.
B) goes down its concentration gradient.
C) goes up its concentration gradient.
D) is at equilibrium.
33) The term that describes the diffusion of water is:
A) simple diffusion.
B) equilibrium.
C) facilitated diffusion.
D) active transport.
E) osmosis.
34) You have lost a lot of blood in an accident. In the emergency room the first thing the doctors
will need to do is replace lost fluids. The fluids they give you should be:
A) isotonic to your cells.
B) hypotonic to your cells.
C) hypertonic to your cells.
D) either hypertonic or isotonic to your cells.
E) either hypertonic or hypotonic to your cells.
35) Plants stay standing upright because of turgor pressure caused by:
A) water rushing into the cells, keeping the cells tight.
B) solutes rushing into the cells, keeping the cells tight.
C) bones that run through the plant, holding it upright.
D) cell walls of the plants supporting and keeping the plants standing upright.
36) Water moves from a:
A) hypotonic environment to a hypertonic environment.
B) hypertonic environment to a hypotonic environment.
C) low free-water solution toward a high free-water solution.
D) solution with more salt to a solution with less salt.
37) Which of the following would be least likely to diffuse through a phospholipid bilayer?
A) carbon dioxide
B) water
C) the small, nonpolar molecule of butane
D) oxygen
E) sodium ions
38) One difference between passive and active transport through a cell membrane is that:
A) active transport makes ATP.
B) active transport requires ATP.
C) passive transport requires ATP.
D) passive transport makes ATP.
39) Facilitated diffusion occurs with the help of:
A) recognition proteins.
B) peripheral proteins.
C) transport proteins.
D) communication proteins.
E) ribosomes.
40) Active transport:
A) moves only large molecules into the cell.
B) causes the production of ATP within the cell.
C) increases the concentration of solute inside the cell.
D) moves substances against their concentration gradient.
41) Facilitated diffusion is similar to simple diffusion because:
A) each requires the use of energy.
B) each requires a protein channel for movement to occur.
C) in both, materials move down their concentration gradient.
D) each utilizes vesicles to move material around the cell.
42) The sodium-potassium pump is an example of:
A) passive transport.
B) receptor-mediated endocytosis.
C) facilitated diffusion.
D) active transport.