DCCC BIO 110 Lecture Exam 2
Questions with Accurate Answers
Plasma Membrane - ANSWERSBoundary that separates the living cell from it's
surroundings; is selectively permeable.
Fluid Mosaic Model - ANSWERSstates that a membrane is a "fluid" structure with a
"mosaic" of various proteins embedded in it.
Cholesterol - ANSWERSAt warm temperatures, this will restrain movement of
phospholipids. At cold temperatures, this remains fluidity.
Proteins - ANSWERS__________________ determine most of the membrane's
functions.
Hydrophobic (non polar) - ANSWERS__________________________molecules, such
as hydrocarbons, can dissolve in the lipid bilayer and pass through the membrane
RAPIDLY.
Glycolipids, Glycoproteins - ANSWERSIn cell-cell recognition, membrane
carbohydrates may be covalently bonded to ____________________ or
__________________.
Transport proteins - ANSWERSallow passage of hydrophilic substances through the
cell membrane.
Channel proteins - ANSWERS___________________ have a hydrophilic channel that
acts as a tunnel through the membrane.
Aquaporins - ANSWERSchannel proteins that facilitate the passage of water
Carrier proteins - ANSWERSbind to molecules and change shape to shuttle them
across the membrane
Diffusion - ANSWERSThe tendency for molecules to spread out evenly into the
available space.
Equilibrium - ANSWERSAs many molecules cross the membrane in one direction as in
the other (No net movement)
Concentration gradient - ANSWERSthe region along which the density of a chemical
substance increases or decreases.
, Passive transport - ANSWERSDiffusion across the membrane is called
_________________________________ because no energy is used (Going DOWN
concentration gradient).
Osmosis - ANSWERSThe diffusion of water across a selectively permeable membrane
Low, high - ANSWERSWater diffuses across a membrane from __________ solute
concentration to ___________ solute concentration until it is equal on both sides.
Tonicity - ANSWERSthe ability of a surrounding solution to cause a cell to gain or lose
water (concentration of something in a liquid).
Isotonic - ANSWERSA solution in which the solute concentration is the same as that
inside the cell; no net water movement across the plasma membrane.
Hypertonic - ANSWERSA solution in which the solute concentration is greater than that
inside the cell; cell loses water.
Hypotonic - ANSWERSA solution in which the solute concentration is less than that
inside the cell; cell gains water.
Turgid - ANSWERSIn a hypotonic solution, the swelling of a plant cell until the wall
opposes uptake of a solution.
Flaccid - ANSWERSPlant may become this if there is no net movement of water into the
cell (isotonic).
Plasmolysis - ANSWERSIn a hypertonic environment, plant cells lose water and
eventually the membranes pull away from the wall. This results in a lethal effect called
_________________.
Osmoregulation - ANSWERSThe control of solute concentrations and water balance.
Facilitated diffusion - ANSWERSIn ____________________________, transport
proteins speed the passive movement of molecules.
Channel Proteins - ANSWERSAllow a specific molecule or ion to cross the membrane.
Exocytosis - ANSWERSTransport vesicles migrate to the membrane, fuse with it, and
release their contents. This is called _________________.
Aquaporins - ANSWERSType of channel protein specifically for water.
Ion or gated channels - ANSWERSChannel proteins that open or close in response to a
stimulus.
Questions with Accurate Answers
Plasma Membrane - ANSWERSBoundary that separates the living cell from it's
surroundings; is selectively permeable.
Fluid Mosaic Model - ANSWERSstates that a membrane is a "fluid" structure with a
"mosaic" of various proteins embedded in it.
Cholesterol - ANSWERSAt warm temperatures, this will restrain movement of
phospholipids. At cold temperatures, this remains fluidity.
Proteins - ANSWERS__________________ determine most of the membrane's
functions.
Hydrophobic (non polar) - ANSWERS__________________________molecules, such
as hydrocarbons, can dissolve in the lipid bilayer and pass through the membrane
RAPIDLY.
Glycolipids, Glycoproteins - ANSWERSIn cell-cell recognition, membrane
carbohydrates may be covalently bonded to ____________________ or
__________________.
Transport proteins - ANSWERSallow passage of hydrophilic substances through the
cell membrane.
Channel proteins - ANSWERS___________________ have a hydrophilic channel that
acts as a tunnel through the membrane.
Aquaporins - ANSWERSchannel proteins that facilitate the passage of water
Carrier proteins - ANSWERSbind to molecules and change shape to shuttle them
across the membrane
Diffusion - ANSWERSThe tendency for molecules to spread out evenly into the
available space.
Equilibrium - ANSWERSAs many molecules cross the membrane in one direction as in
the other (No net movement)
Concentration gradient - ANSWERSthe region along which the density of a chemical
substance increases or decreases.
, Passive transport - ANSWERSDiffusion across the membrane is called
_________________________________ because no energy is used (Going DOWN
concentration gradient).
Osmosis - ANSWERSThe diffusion of water across a selectively permeable membrane
Low, high - ANSWERSWater diffuses across a membrane from __________ solute
concentration to ___________ solute concentration until it is equal on both sides.
Tonicity - ANSWERSthe ability of a surrounding solution to cause a cell to gain or lose
water (concentration of something in a liquid).
Isotonic - ANSWERSA solution in which the solute concentration is the same as that
inside the cell; no net water movement across the plasma membrane.
Hypertonic - ANSWERSA solution in which the solute concentration is greater than that
inside the cell; cell loses water.
Hypotonic - ANSWERSA solution in which the solute concentration is less than that
inside the cell; cell gains water.
Turgid - ANSWERSIn a hypotonic solution, the swelling of a plant cell until the wall
opposes uptake of a solution.
Flaccid - ANSWERSPlant may become this if there is no net movement of water into the
cell (isotonic).
Plasmolysis - ANSWERSIn a hypertonic environment, plant cells lose water and
eventually the membranes pull away from the wall. This results in a lethal effect called
_________________.
Osmoregulation - ANSWERSThe control of solute concentrations and water balance.
Facilitated diffusion - ANSWERSIn ____________________________, transport
proteins speed the passive movement of molecules.
Channel Proteins - ANSWERSAllow a specific molecule or ion to cross the membrane.
Exocytosis - ANSWERSTransport vesicles migrate to the membrane, fuse with it, and
release their contents. This is called _________________.
Aquaporins - ANSWERSType of channel protein specifically for water.
Ion or gated channels - ANSWERSChannel proteins that open or close in response to a
stimulus.
