CH 5: Cell Membranes

Practice Test

answers

The movement of a substance toward an area of lower concentration is called

________.1. diffusion

2. osmosis

3. active transport

4. exocytosis

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Which component in the cell membrane restricts the passage of water-soluble

substances?

1. glycolipids

2. protein

3. oligosaccharides

4. phospholipid

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A membrane protein with two hydrophilic domains will generally:

1. be an enzyme

2. be an integral membrane protein

3. be a peripheral membrane protein

4. be involved with cell recognition

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Which type of membrane protein will bind to a signal molecule such

as a hormone?

1. adhesion

2. passive transporter

3. cell-to-cell communication

4. receptor

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Communication proteins permit ________.

1. a cell to respond to extracellular signals

2. cells to import signal molecules from the extracellular environment

3. signaling between adjacent cells

4. body cells to distinguish foreign cells

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Which combination of conditions would promote the most rapid diffusion across a

cell membrane?

1. large molecule, high temperature, large concentration gradient

2. large molecule, low temperature, small concentration gradient

3. small molecule, low temperature, small concentration gradient

4. small molecule, high temperature, large concentration gradient

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The term "selective permeability" describes the characteristic of membranes that

________.

1. restrict the passage of polar molecules

2. provide an anchoring between adjacent cells

3. allow membrane proteins to float freely within the membrane

4. permit some molecules to cross the membrane while preventing others from crossing

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In the absence of a specific carrier protein, which type of molecule would be least likely

to cross the membrane?

1. one that is large and polar

2. one that is small and nonpolar

3. one that is large and nonpolar

4. one that is small and polar

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Why is diffusion the method by which O2 and CO2 are transported across the cell

membrane?

1. it is faster than active transport

2. it allows ions and molecules to accumulate at higher concentrations within the cell than in the surrounding environment

3. the phospholipid bilayer is permeable to small, non-polar molecules

4. protein components are needed in the cell membrane for diffusion to occur

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Nerve cells contain an unusually high concentration of potassium; how are they able to obtain concentrations of

potassium greater than those of the surrounding extracellular environment?

1. reverse diffusion

2. reverse osmosis

3. active transport

4. facilitated diffusion

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Which of the following is a characteristic of active transport?

1. solute movement across the membrane is toward the side with the higher concentration

2. specific membrane proteins are required but no energy is needed

3. only molecules with potential energy greater than ATP are transported

4. it is a passive process

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Proteins in membranes can provide all of the following functions except ________.

1. carriers for polar molecules

2. insulation

3. receptors

4. enzymes

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Imagine cells suspended in a fluid to which a large amount of salt is suddenly added. If the cell membrane were impermeable to the salt, the cell would subsequently

________.

1. die

2. swell as it gains water osmotically

3. shrink as it loses water osmotically

4. experience no changes; since it's impermeable, salt has no effect

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Osmosis can be described as ________.

1. movement of water from a region of high solute concentration to a region of low solute concentration

2. movement of solute from an area of low solute concentration to an area of high solute concentration

3. water molecules colliding with one another and the wall of a container

4. movement of water across a membrane from an area of low solute concentration to an area of high solute concentration

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Which graphic, A, B, or C, portrays what would happen to cells in a hypertonic environment?

1 2 3

A

1.

B

2.

C

3.

The cell membrane ________.

1. is selectively permeable

2. has a bilayered phospholipid-protein structure

3. defines the boundary of the cell

4. all of the choices

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The most abundant lipid in a cell membrane is ________.

1. phospholipid

2. steroids

3. cholesterol

4. triglycerides

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When a plant cell is placed in a hypotonic solution the plant cell will

1. Lose water from its vacuole.

2. Not be affected

3. Take in water and potentially burst

4. Take in water and expand up to its cell wall.

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What feature of a vesicle would indicate an endocytotic formation?

1. there would not be any receptor proteins

2. it would contain cytoplasmic fluid

3. it would contain extracellular fluid

4. integral proteins would be absent

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Phagocytosis is one type of ________.

1. active transport

2. osmosis

3. exocytosis

4. endocytosis

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