BS 161 EXAM 2 011 and 012 UPDATED
ACTUAL Questions and CORRECT
Answers
What is the structure of a cell membrane? - CORRECT ANSWER - A phospholipid
bilayer with hydrophilic heads facing outward and hydrophobic tails facing inward.
Why can small nonpolar molecules cross membranes easily? - CORRECT ANSWER -
Because they dissolve in the hydrophobic core of the lipid bilayer.
Which types of molecules cannot cross the membrane easily? - CORRECT ANSWER -
Large polar molecules and charged ions because they are repelled by the hydrophobic interior.
What are transport proteins? - CORRECT ANSWER - Proteins that help specific
molecules cross the membrane, including channels and carriers.
What are the two main types of transport proteins? - CORRECT ANSWER - Channels and
carrier proteins.
What drives passive transport? - CORRECT ANSWER - The concentration gradient;
molecules move from high to low concentration without energy input.
What is simple diffusion? - CORRECT ANSWER - Movement of small, nonpolar
molecules directly through the lipid bilayer without protein help or energy.
What is facilitated diffusion? - CORRECT ANSWER - Passive transport of polar or
charged molecules through channel or carrier proteins.
What are ion channels? - CORRECT ANSWER - Pores in the membrane that allow
specific ions to cross based on size and charge.
, How do carrier proteins move molecules? - CORRECT ANSWER - They change shape
after binding the molecule to move it across the membrane.
What is osmosis? - CORRECT ANSWER - Passive diffusion of water through a
selectively permeable membrane toward higher solute concentration.
What are aquaporins? - CORRECT ANSWER - Channel proteins that allow rapid
movement of water in and out of cells.
What does 'water follows solutes' mean? - CORRECT ANSWER - Water moves toward
areas with higher solute concentration (lower water concentration).
Define isotonic solution. - CORRECT ANSWER - Solution with equal solute
concentration inside and outside the cell; no net water movement.
Define hypertonic solution. - CORRECT ANSWER - Solution with higher solute
concentration outside the cell; water exits the cell causing it to shrink.
Define hypotonic solution. - CORRECT ANSWER - Solution with lower solute
concentration outside the cell; water enters the cell causing it to swell or burst.
Why must IV fluids be isotonic? - CORRECT ANSWER - To prevent red blood cells from
bursting (in hypotonic) or shrinking (in hypertonic) conditions.
What is active transport? - CORRECT ANSWER - Movement of molecules against their
concentration gradient, requiring energy input.
What is primary active transport? - CORRECT ANSWER - Uses ATP directly to move
molecules across membranes.
ACTUAL Questions and CORRECT
Answers
What is the structure of a cell membrane? - CORRECT ANSWER - A phospholipid
bilayer with hydrophilic heads facing outward and hydrophobic tails facing inward.
Why can small nonpolar molecules cross membranes easily? - CORRECT ANSWER -
Because they dissolve in the hydrophobic core of the lipid bilayer.
Which types of molecules cannot cross the membrane easily? - CORRECT ANSWER -
Large polar molecules and charged ions because they are repelled by the hydrophobic interior.
What are transport proteins? - CORRECT ANSWER - Proteins that help specific
molecules cross the membrane, including channels and carriers.
What are the two main types of transport proteins? - CORRECT ANSWER - Channels and
carrier proteins.
What drives passive transport? - CORRECT ANSWER - The concentration gradient;
molecules move from high to low concentration without energy input.
What is simple diffusion? - CORRECT ANSWER - Movement of small, nonpolar
molecules directly through the lipid bilayer without protein help or energy.
What is facilitated diffusion? - CORRECT ANSWER - Passive transport of polar or
charged molecules through channel or carrier proteins.
What are ion channels? - CORRECT ANSWER - Pores in the membrane that allow
specific ions to cross based on size and charge.
, How do carrier proteins move molecules? - CORRECT ANSWER - They change shape
after binding the molecule to move it across the membrane.
What is osmosis? - CORRECT ANSWER - Passive diffusion of water through a
selectively permeable membrane toward higher solute concentration.
What are aquaporins? - CORRECT ANSWER - Channel proteins that allow rapid
movement of water in and out of cells.
What does 'water follows solutes' mean? - CORRECT ANSWER - Water moves toward
areas with higher solute concentration (lower water concentration).
Define isotonic solution. - CORRECT ANSWER - Solution with equal solute
concentration inside and outside the cell; no net water movement.
Define hypertonic solution. - CORRECT ANSWER - Solution with higher solute
concentration outside the cell; water exits the cell causing it to shrink.
Define hypotonic solution. - CORRECT ANSWER - Solution with lower solute
concentration outside the cell; water enters the cell causing it to swell or burst.
Why must IV fluids be isotonic? - CORRECT ANSWER - To prevent red blood cells from
bursting (in hypotonic) or shrinking (in hypertonic) conditions.
What is active transport? - CORRECT ANSWER - Movement of molecules against their
concentration gradient, requiring energy input.
What is primary active transport? - CORRECT ANSWER - Uses ATP directly to move
molecules across membranes.
