LSU Bio 1201 exam 2 UPDATED
Questions and CORRECT Answers
why are membranes called phospholipid bilayers? - CORRECT ANSWER - phospholipids
have hydrophilic head and hydrophobic tail, hydrophobic face inside of cell making 2 layers
what is meant by fluid mosaic? - CORRECT ANSWER - Mosaic of proteins drifting
laterally in fluid bilayer of phospholipids
how are membranes adjusted for different temperatures? - CORRECT ANSWER -
membrane fluidity adjusted by changing the ratio of unsaturated to saturated fatty acids
how do the relative amounts of saturated and unsaturated fats change? - CORRECT
ANSWER - if you are in a cold environment you want more saturated fats for your
membranes to be fluid; warm environment you want more saturated fats to make your
membranes more solid
what is meant by membrane fluidity? - CORRECT ANSWER - not too solid, not too fluid
why is fluidity an important property? - CORRECT ANSWER - preserves membrane
function
Henrique and Hanson performed experiments with pigs and examined the effects on the relative
amounts of saturated and unsaturated fats. What did they find? - CORRECT ANSWER -
found that membrane fluidity can acclimate to temperature; pigs raised wearing underwear in a
hot room had subcutaneous fats with higher melting point
what types of molecules can move easily across the membrane? - CORRECT ANSWER -
small nonpolar molecules, gases, steroid hormones, and water
, what is simple diffusion? - CORRECT ANSWER - down the concentration gradient; does
not require supplied energy; does not use a carrier molecule
what is facilitated diffusion? - CORRECT ANSWER - down the concentration gradient;
employs carrier molecule; does not require supplied energy
what is active transport? - CORRECT ANSWER - work must me done; must use supplied
energy; employs carrier molecule
for which transport processes are carrier molecules involved? - CORRECT ANSWER -
facilitated diffusion and active transport
which transport processes require the input of additional energy? - CORRECT ANSWER -
active transport
what is a semi-permeable barrier? - CORRECT ANSWER - only some types of molecules
pass through
when equilibrium is reached in diffusion: does movement of molecules stop? - CORRECT
ANSWER - no
when equilibrium is reached in diffusion: does the net movement of molecules stop? -
CORRECT ANSWER - yes
what is meant by hypertonic? - CORRECT ANSWER - lower water potential; more
solutes dissolved; tend to gain water via osmosis
what is meant by hypertonic? - CORRECT ANSWER - higher water potential; fewer
solutes dissolved; will tend to lose water via osmosis
Questions and CORRECT Answers
why are membranes called phospholipid bilayers? - CORRECT ANSWER - phospholipids
have hydrophilic head and hydrophobic tail, hydrophobic face inside of cell making 2 layers
what is meant by fluid mosaic? - CORRECT ANSWER - Mosaic of proteins drifting
laterally in fluid bilayer of phospholipids
how are membranes adjusted for different temperatures? - CORRECT ANSWER -
membrane fluidity adjusted by changing the ratio of unsaturated to saturated fatty acids
how do the relative amounts of saturated and unsaturated fats change? - CORRECT
ANSWER - if you are in a cold environment you want more saturated fats for your
membranes to be fluid; warm environment you want more saturated fats to make your
membranes more solid
what is meant by membrane fluidity? - CORRECT ANSWER - not too solid, not too fluid
why is fluidity an important property? - CORRECT ANSWER - preserves membrane
function
Henrique and Hanson performed experiments with pigs and examined the effects on the relative
amounts of saturated and unsaturated fats. What did they find? - CORRECT ANSWER -
found that membrane fluidity can acclimate to temperature; pigs raised wearing underwear in a
hot room had subcutaneous fats with higher melting point
what types of molecules can move easily across the membrane? - CORRECT ANSWER -
small nonpolar molecules, gases, steroid hormones, and water
, what is simple diffusion? - CORRECT ANSWER - down the concentration gradient; does
not require supplied energy; does not use a carrier molecule
what is facilitated diffusion? - CORRECT ANSWER - down the concentration gradient;
employs carrier molecule; does not require supplied energy
what is active transport? - CORRECT ANSWER - work must me done; must use supplied
energy; employs carrier molecule
for which transport processes are carrier molecules involved? - CORRECT ANSWER -
facilitated diffusion and active transport
which transport processes require the input of additional energy? - CORRECT ANSWER -
active transport
what is a semi-permeable barrier? - CORRECT ANSWER - only some types of molecules
pass through
when equilibrium is reached in diffusion: does movement of molecules stop? - CORRECT
ANSWER - no
when equilibrium is reached in diffusion: does the net movement of molecules stop? -
CORRECT ANSWER - yes
what is meant by hypertonic? - CORRECT ANSWER - lower water potential; more
solutes dissolved; tend to gain water via osmosis
what is meant by hypertonic? - CORRECT ANSWER - higher water potential; fewer
solutes dissolved; will tend to lose water via osmosis
