Chapter 5 Quiz Questions

Endocytosis of discrete particles is called ___________ while endocytosis of liquids is called _____________.

phagocytosis; pinocytosis

Red blood cells add a __________ group to any entering glucose molecule, which prevents the glucose from passing back across the membrane.

phosphate

The lipid bilayer that forms the core of all cell membranes is composed primarily of ______________

phospholipids

All cell membranes are composed of ______________ in a bilayer which provides a flexible ______________ and a barrier to permeability.

phospholipids; matrix

Select all that apply Select the statements that are true about ions. A. They interact well with polar molecules. B. They are repelled by the hydrophobic interior of the lipid bilayer. C. They can easily cross the plasma membrane without the help of special transport proteins.

A, B

Select all that apply Which of the following are required for the sodium potassium pump in cells to work? A. ATP B. Carrier proteins C. Ion channels D. Aquaporins E. Secretory vesicles

A, B (ATP and carrier proteins)

Select all that apply How do active and passive transport differ? Choose all that apply. A. Only active transport can move a substance against its concentration gradient. B. Only active transport relies on an expenditure of energy by the cell itself, usually from ATP. C. Only active transport relies on carrier proteins D. Cells use active transport only for organic molecules. Inorganic molecules and ions are only moved by passive transport.

A, B (Only active transport can move a substance against its concentration gradient; only active transport relies on an expenditure of energy by the cell itself; usually from ATP)

Select all that apply Which of the following accurately describe the functions of transmembrane proteins? A. They transmit information into the cell. B. They can transport molecules across the membrane. C. They control the fluidity of the membrane D. They provide a permeability barrier for other proteins.

A, B (they transmit information into the cell; they can transport molecules across the membrane)

Select all that apply Select the accurate statements concerning membrane fluidity. A. Unanchored proteins are relatively free to move around laterally within the membrane. B. The degree of membrane fluidity varies depending on the composition of the membrane. C. Phospholipids are relatively free to move around laterally within the membrane. D. All membranes have essentially the same composition and degree of fluidity.

A, B, C

Select all that apply Select the statements that are true of gated channels? A. They can open and close in response to electrical stimuli. B. They have a hydrated interior through which polar molecules and ions can move when open. C. They can open and close in response to chemical stimuli. D. They have a hydrated interior through which nonpolar molecules and ions can move when open.

A, B, C

Select all that apply Which of the following are key functions carried out by membrane proteins? A. Connect adjacent cells and hold them together B. Receive external chemical messages C. Code for the production of new polynucleotides D. Attach the membrane to the cytoskeleton E. Transport oxygen into the cell

A, B, D

Select all that apply Choose the three groups of lipids found in eukaryotic cells. A. Glycerol phospholipids B. Sterols C. Triglycerides D. Sphingolipids E. Integral bilayer lipids

A, B, D (glycerol phospholipids, sterols, sphingolipids)

Select all that apply Which of the following are key functions carried out by membrane proteins? A. Receive external chemical messages B. Transport specific ions and molecules across the membrane C. Short-term storage of excess energy D. Catalyze specific chemical reactions on the surface of the membrane E. Function as cell-surface identity markers

A, B, D, E

The major barrier to crossing a biological membrane is the hydrophobic interior of the membrane that repels what kind of molecules? A. Polar molecules B. Transmembrane proteins C. Peripheral proteins D. Nonpolar molecules E. Glycoproteins

A. polar molecules

Select all that apply Some membrane proteins are attached to the surface of the membrane by special molecules that associate strongly with phospholipids. Which of the following describes the anchoring molecules? A. They have chemical bonding domains that link them directly to the membrane proteins. B. They have polar regions that insert into the internal portion of the lipid bilayer. C. They are modified lipids. D. They do not link directly to the membrane proteins.

A, C

Select all that apply Which of the following describe transmembrane proteins? Choose all that apply. A. They are anchored in the membrane because their nonpolar regions are "pushed" into the interior of the membrane by hydrophobic exclusion. B. They have polar regions that are held within the interior of the lipid bilayer and nonpolar regions that protrude from both sides of the membrane. C. They actually span the membrane's lipid bilayer.

A, C

Select all that apply The hydrophobic region of a transmembrane protein which extends through the lipid bilayer contacting the nonpolar interior of the membrane might be composed of which of the following (choose all that apply)? A. α helices containing non-polar amino acids B. β pleated sheets containing polar amino acids C. β pleated sheets containing non-polar amino acids D. α helices containing polar amino acids

A, C (either a helices or b pleated sheets containing non-polar amino acids)

Select all that apply Which of the following describes the sodium-potassium pump? A. It is an active transport mechanism. B. It transports both sodium ions and potassium ions down their respective concentration gradients. C. It uses energy from ATP to alter the conformation of the carrier protein. D. It moves sodium ions and potassium ions across the membrane in opposite directions.

A, C, D

Select all that apply Which of the following statements about endocytosis are true? A. Virtually all eukaryotic cells carry out endocytosis. B. Endocytosis can only be used to move materials down their own concentration gradient. C. During endocytosis, a segment of the plasma membrane pinches off to form a vacuole or vesicle inside the cell. D. Phagocytosis, pinocytosis, and receptor-mediated endocytosis are 3 different types of endocytosis.

A, C, D

Which of the following substances are transported across membranes by carrier proteins? A. Ions B. Small organelles C. Amino acids D. Lipids E. Sugars

A, C, E (ions, amino acids, sugars)

Select all that apply Which of the following statements about ion channels are true? A. They are used to transport ions across the membrane. B. Ions can diffuse through the channel only in one direction for a given ion channel. C. They allow any ions with a given charge (for example 1+) to pass through the membrane. D. Some can be opened or closed in response to a specific stimulus.

A, D (They are used to transport ions across the membrane and some can be opened or closed in response to a specific stimulus)

Select all that apply In cell membranes, the interior of the lipid bilayer repels which of the following? A. Polar molecules B. Hydrophobic molecules C. Nonpolar molecules D. Ions E. Hydrophilic molecules

A, D, E (polar molecules, ions, and hydrophillic molecules)

Oxygen diffuses across the plasma membrane due to which of the following? A. All oxygen molecules are in constant random motion. B. All oxygen molecules move up their concentration gradient until equilibrium is reached. C. All oxygen molecules move down their concentration gradient until equilibrium is reached. D. Transport proteins actively move oxygen molecules across the membrane.

A. All oxygen molecules are in constant random motion

A defining feature of biological membranes is the presence of which of the following? A. A lipid bilayer B. A lipid monolayer C. A carbohydrate monolayer D. A protein bilayer

A. a lipid bilayer

The red blood cell carrier that transports bicarbonate ions in one direction transports ______ ions in the opposite direction. A. chloride B. oxygen C. bicarbonate D. glucose

A. chloride

What is the immediate source of the energy needed to power the sodium-potassium pump? A. Hydrolysis of ATP B. A gradient of sodium ions C. The kinetic energy of the sodium and potassium ions D. Synthesis of ATP

A. hydrolysis of ATP

Transport that requires a cell to expend some of its own energy, typically from _______, is called __________ transport.

ATP; active

Select all that apply Which regions of a phospholipid molecule are hydrophilic? A. Fatty acid hydrocarbon chains B. Polar or charged molecule attached to the phosphate group C. Phosphate group

B, C (polar or charged molecule attached to the phosphate group; phosphate group)

Select all that apply The following substances all move across the plasma membrane of red blood cells by diffusion. Which ones move by facilitated diffusion? A. Oxygen B. Bicarbonate ions C. Glucose D. Chloride ions

B, C, D

Choose all that apply Transmembrane proteins include: A. spectrins B. channels C. receptors D. clathrins E. carriers

B, C, E (channels, receptors, carriers)

Select all that apply How does lipid composition affect membrane fluidity? A. Unsaturated fatty acids tend to make the membrane less fluid because kinks introduced by the double bonds keep them from packing together well. B. Saturated fatty acids tend to make the membrane less fluid because they pack together well. C. Lipid composition has no effect on the fluidity of membranes. D. Sterols, such as cholesterol, can either increase or decrease membrane fluidity depending on temperature.

B, D

Select the true statements about cell membranes. A. All membranes have essentially the same composition and degree of fluidity. B. The degree of membrane fluidity varies depending on the composition of the membrane. C. The surface (the side facing the cytoplasm or the extracellular fluid) of the phospholipid bilayer is hydrophobic. D. Individual lipids and unanchored proteins are relatively free to move around laterally within the lipid bilayer.

B, D

Select all that apply Which of the following is true of cations? A. Have a negative electric charge. B. Have a positive electric charge. C. Have an equal number of protons and electrons. D. Have an unequal number of protons and electrons.

B, D (have a positive electric charge, have an unequal number of protons and electrons)

Select all that apply Which of the following are true of the plasma membrane? A. It is composed mainly of carbohydrates and proteins. B. It is selectively permeable. C. It is fully permeable. D. It is fluid.

B, D (it is selectively permeable and it is fluid)

Select all that apply Which of the following are typical components of biological membranes? A. DNA B. Proteins C. RNA D. Lipids

B, D (proteins and lipids)

Select all that apply Identify the four main components of all eukaryotic membranes. A. Extracellular matrix B. Transmembrane proteins C. Actin filaments D. Interior protein network E. Lipid bilayer F. Cell surface markers

B, D, E, F (transmembrane proteins, interior protein network, lipid bilayer, cell surface markers)

What is the name of the process during which the plasma membrane surrounds and envelopes smaller cells, solid particles, or liquids. A. Bulk assimilation B. Endocytosis C. Macrophagy D. Exocytosis

B. Endocytosis

Which of the following is not one of the four main components of all plasma membranes? A. Transmembrane proteins B. Extracellular matrix C. Lipid bilayer D. Interior protein network E. Cell surface markers

B. Extracellular matrix (extracellular matrix is the OUTSIDE of the cell, not a component that makes up the structures and functions of plasma membranes)

Which of the following transmembrane proteins are likely to be found in membranes that form tubular structures? A. Adhesion proteins B. Reticulons C. Actins D. Coating proteins

B. Reticulons

During facilitated diffusion, how do carrier proteins transport solutes across the membrane? A. They increase the concentration gradient across the membrane to speed up the rate of diffusion. B. They bind specifically to the solute being transported. C. They neutralize ions so they can diffuse across the hydrophobic interior of the lipid bilayer. D. They add a phosphate group to the solutes being transported.

B. They bind specifically to the solute being transported

When phospholipids are placed in water, they spontaneously form which of the following? A. Branched chains B. A bilayer C. Unbranched chains D. A double helix E. 5-sided rings

B. a bilayer

Net movement of a substance from a region where it has a higher concentration to a region where it has a lower concentration is called which of the following? A. Endocytosis B. Diffusion C. Active transport D. Osmosis E. Equilibrium

B. diffusion

When a channel protein or carrier protein assists in diffusion, which of the following is observed? A. Dialysis B. Facilitated diffusion C. Endocytosis D. Active transport E. Simple diffusion

B. facilitated diffusion

Energy released from the hydrolysis of ATP is used to change the conformation of the sodium-potassium pump which results in changes in A. number of transmembrane domains of this protein B. the protein's affinity for Na+ and K+. C. the diameter of the two channels formed by this protein

B. the protein's affinity for Na+ and K+

What is the function of transmembrane proteins called reticulons? A. They glue adjacent membranes together. B. They can cause a membrane to bend or even form a tube. C. They form specialized connections between two cells that are touching. D. They stabilize portions of the membrane that are flat.

B. they can cause a membrane to bend or even form a tube

Which of the following is the major function of the phospholipid bilayer? A. To anchor proteins to specific sites on the exterior of the plasma membrane. B. To impose a barrier to permeability. C. To transmit information into the cell.

B. to impose a barrier to permeability

What is the name of carrier proteins that transport a single type of molecule or ion? A. Antiporters B. Uniporters C. Monoporters D. Symporters

B. uniporters

Which of the following best describes the amount of energy used by animal cells in the active transport of Na+ and K+ from areas of low concentration to areas of high concentration? A. No energy is expended by an animal cell in the transport of Na+ and K+. B. Less than one-third of all the energy expended by an animal cell that is not actively dividing is used in the transport of Na+ and K+. C. More than one-third of all the energy expended by an animal cell that is not actively dividing is used in the transport of Na+ and K+.

C

Name the type of endocytosis, during which molecules bind to specific proteins embedded in the plasma membrane before they are engulfed by the cell. The molecules that are transported into the cell have a conformation that fits snugly with the protein, to which they attach before they are engulfed. A. Pinocytosis B. Membrane-mediated phagocytosis C. Receptor-mediated endocytosis D. Protein-mediated endocytosis

C.

During the Na/K pump cycle, the protein binds a molecule of ATP and soon after, the ATP is hydrolyzed and a phosphate is transferred to an amino acid in the pump's structure. What is the affinity of the pump for sodium and potassium ions at this point? A. High affinity for both sodium and potassium B. High affinity for sodium and low affinity for potassium C. Low affinity for sodium and high affinity for potassium D. Low affinity for both sodium and potassium

C. Low affinity for sodium and high affinity for potassium

How do carrier proteins differ from channel proteins? A. Only carrier proteins have a hydrophilic interior channel. B. Only carrier proteins are selective for one type of molecule. C. Only carrier proteins actually bind to the substance being transported. D. Only carrier proteins can facilitate net movement of a substance down its concentration gradient.

C. Only carrier proteins actually bind to the substance being transported

Plasma membranes allow some substances to pass through easily while other substances only pass through very slowly or not at all. For that reason, plasma membranes are considered which of the following? A. Fluid B. Amphipathic C. Selectively permeable D. Partially permeable E. Hydrophobic

C. Selectively permeable

Cells continually exchange materials and information with their environment. This exchange is crucial A. only in a multicellular organism. B. only in dividing cells, whether they make up a unicellular or a multicellular organism. C. for all the processes occurring in a cell. D. only for nutrient acquisition.

C. for all the processes occurring in a cell

Some membrane proteins are anchored to the surface of the membrane by molecules that associate strongly with phospholipids and insert into the lipid bilayer. These molecules are A. polar proteins. B. cytoskeletal proteins. C. modified lipids. D. DNA.

C. modified lipids

Which of the following makes up the bilayer of every cell membrane? A. Proteins B. Cholesterol C. Phospholipids D. Saturated fats E. Unsaturated fats

C. phospholipids

Why is active transport such an important cell process? A. Only active transport can move a substance from an area where it has a higher concentration to an area where it has a lower concentration. B. Only active transport can move a hydrophobic substance across the lipid bilayer of the plasma membrane. C. Only active transport can move a hydrophilic substance across the lipid bilayer of the plasma membrane. D. Only active transport can move a substance from an area where it has a lower concentration to an area where it has a higher concentration.

D

Phagocytosis is one of the mechanisms of which of the following? A. Pinocytosis B. Exocytosis C. Passive transport D. Endocytosis

D. Endocytosis

Substances that cannot easily cross the lipid bilayer can still diffuse across the plasma membrane with the help of which of the following? A. Specific transmembrane proteins or peripheral proteins B. Specific glycolipids or glycoproteins C. Specific hydrophilic proteins or hydrophobic proteins D. Specific channel proteins or carrier proteins

D. Specific channel proteins or carrier proteins

During receptor-mediated endocytosis, binding of the target molecules to their matching receptors triggers what? A. Hydrolysis of ATP B. Fusion of a secretory vesicle with the plasma membrane C. Phosphorylation of the receptor proteins D. The formation of an endocytic vesicle

D. The formation of an endocytic vesicle

Which of the following is true of channel proteins? A. They have a hydrophilic interior through which nonpolar molecules can pass. B. They have a hydrophobic interior through which nonpolar molecules can pass. C. They have a hydrophobic interior through which polar molecules can pass. D. They have a hydrophilic interior through which polar molecules can pass.

D. They have a hydrophilic interior through which polar molecules can pass

How do red blood cells promote the movement of glucose into the cell? A. They actively pump glucose into the cell using energy from ATP. B. They form a channel in the membrane through which glucose moves. C. They phosphorylate glucose before it enters the cell so it can cross the membrane more easily. D. They phosphorylate glucose after it enters the cell in order to maintain a steep concentration gradient for unphosphorylated glucose.

D. They phosphorylate glucose after it enters the cell in order to maintain a steep concentration gradient for unphosphorylated glucose

The diffusion of which molecules across a selectively permeable membrane is called osmosis? A. Glucose B. NaCl C. Protein D. Water

D. Water

Why do ions need membrane transport proteins to help them cross the plasma membrane? A. Because they are not proteins B. Because of their size C. Because they are not charged D. Because of their charge

D. because of their charge

In order to survive, grow, and reproduce, a cell must A. have internal membranes B. exchange information with other cells C. absorb organic molecules from its environment D. exchange materials and information with its environment E. have a nucleus

D. exchange materials and information with its environment

Which of the following describes passive transport? A. It requires energy from ATP. B. It does not require a concentration gradient. C. It can only be used to move materials up a concentration gradient. D. It does not require an expenditure of energy by the cell itself.

D. it does not require an expenditure of energy by the cell itself

The _________ transport of sodium and potassium ions from areas of ______ concentration to areas of ________ concentration requires more than one-third of all the energy expended by a non-dividing animal cell.

active; low; high

While __________ transport requires the cell to expend some of its own energy, ___________ transport does not.

active; passive

Transport proteins that actually bind to the specific substance being transported across the membrane are called ___________ proteins.

carrier

Transport proteins that have a hydrophilic interior space through which specific substances can move across the membrane in either direction are called ___________ proteins.

channel

The two main categories of _______ __________ are endocytosis and exocytosis.

bulk transport

Amino acids, sugars and ions are transported across the plasma membrane by ___________ proteins.

carrier

Of the 2 types of transport proteins that mediate facilitated diffusion, only ___________ proteins actually bind with the substance being transported while ____________ proteins simply provide a hydrophilic space for the substance to move through.

carrier; channel

Ions that carry an overall positive charge are called __________ while those that carry an overall negative charge are called __________.

cations; anions

Many substances that are repelled by the hydrophobic interior of the lipid bilayer can readily diffuse across the plasma membrane with the help of specific __________ proteins or __________ proteins. These transporter proteins are typically transmembrane proteins.

channel; carrier

Ion ____________ have a hydrated interior that spans the membrane and allows ions to diffuse through.

channels

Due to the constant random motion of its atoms and molecules, a substance will exhibit net movement from a region where it has a higher concentration to a region where it has a lower concentration. This net movement is called ___________.

diffusion

During ______________, the plasma membrane surrounds and envelopes smaller cells, solid particles, or liquids.

endocytosis

Based on the direction of movement, bulk transport can be divided into two main categories: _____________ and ______________.

endocytosis; exocytosis

Diffusion that is assisted by a channel protein or carrier protein is called ___________ diffusion.

facilitated

Channel proteins that can be opened or closed in response to a specific stimulus are called _________ channels.

gate

The lack of double bonds in saturated fats allow them to pack together tightly, and therefore the membrane is _______ fluid. The presence of double bonds in unsaturated fats prevent them from packing together tightly, and therefore the membrane is ________ fluid.

less; more

Cellular ____________ are said to be selectively _____________ because they allow some substances to pass through easily while other substances pass through very slowly or not at all.

membranes; permeable

The diffusion of water across a selectively permeable membrane is called __________.

osmosis

Transport that occurs without a cell expending any of its own energy is called ___________ transport.

passive

Although a eukaryotic cell membrane can contain many different lipids, they can be classified in three groups: glycerol phospholipids, _________, and ________________. (When answering the question think about the lipids found in membranes, not about all the lipids that an organism makes!)

sterols; sphingolipids

Carrier proteins that transport 2 different types of molecules or ions may be either __________ or antiporters.

symporters