BIOLOGY 1201 EXAM 2 2026 SOLVED
QUESTIONS ANSWER KEY APLUS
◉ phospholipid bilayer.
Answer: structure of cell membrane
◉ integral proteins.
Answer: proteins that penetrate the hydrophobic interior of the lipid
bilayer but do not go all the way through
◉ transmembrane proteins.
Answer: proteins that go through the cell membrane
◉ selective permeability.
Answer: property of biological membranes that allows some
substances to cross more easily than others
◉ fluid mosaic model.
Answer: model of the cell membrane that refers to phospholipids as
freely moving laterally in the membrane, but rarely flipping from
one side of the bilayer to the other side
,◉ cholestrol.
Answer: reduces membrane fluidity
◉ N-terminus.
Answer: amino end of transmembrane helix that sticks out on
extracellular side
◉ C-terminus.
Answer: carboxyl end of transmembrane helix that sticks out of
cytoplasmic side
◉ alpha helix.
Answer: coiled region constituting one form of the secondary
structure of proteins, arising from a specific pattern of hydrogen
bonding between atoms of the polypeptide backbone (not the side
chains)
◉ diffusion.
Answer: transport that requires no energy (passive) and no proteins,
net movement of solute molecules down the gradient (rate
depending on concentration) until concentration reaches
equilibrium
◉ facilitated diffusion.
, Answer: passive transport of solutes across cell membrane down
concentration gradient with the aid of carrier proteins
◉ active transport.
Answer: Energy-requiring process that moves solutes across a cell
membrane against a concentration difference using a transport
protein
◉ Equilibrium.
Answer: balance of solutes in a solution
◉ Osmosis.
Answer: diffusion of water across a selectively permeable
membrane, water is moving
◉ hypotonic.
Answer: relatively lower solute concentration, high water content
◉ hypertonic.
Answer: relatively higher solute concentration, low water content
◉ isotonic.
QUESTIONS ANSWER KEY APLUS
◉ phospholipid bilayer.
Answer: structure of cell membrane
◉ integral proteins.
Answer: proteins that penetrate the hydrophobic interior of the lipid
bilayer but do not go all the way through
◉ transmembrane proteins.
Answer: proteins that go through the cell membrane
◉ selective permeability.
Answer: property of biological membranes that allows some
substances to cross more easily than others
◉ fluid mosaic model.
Answer: model of the cell membrane that refers to phospholipids as
freely moving laterally in the membrane, but rarely flipping from
one side of the bilayer to the other side
,◉ cholestrol.
Answer: reduces membrane fluidity
◉ N-terminus.
Answer: amino end of transmembrane helix that sticks out on
extracellular side
◉ C-terminus.
Answer: carboxyl end of transmembrane helix that sticks out of
cytoplasmic side
◉ alpha helix.
Answer: coiled region constituting one form of the secondary
structure of proteins, arising from a specific pattern of hydrogen
bonding between atoms of the polypeptide backbone (not the side
chains)
◉ diffusion.
Answer: transport that requires no energy (passive) and no proteins,
net movement of solute molecules down the gradient (rate
depending on concentration) until concentration reaches
equilibrium
◉ facilitated diffusion.
, Answer: passive transport of solutes across cell membrane down
concentration gradient with the aid of carrier proteins
◉ active transport.
Answer: Energy-requiring process that moves solutes across a cell
membrane against a concentration difference using a transport
protein
◉ Equilibrium.
Answer: balance of solutes in a solution
◉ Osmosis.
Answer: diffusion of water across a selectively permeable
membrane, water is moving
◉ hypotonic.
Answer: relatively lower solute concentration, high water content
◉ hypertonic.
Answer: relatively higher solute concentration, low water content
◉ isotonic.
