LSU Bio 1201 exam 2 QUESTIONS &
ANSWERS 100% CORRECT!!
why are membranes called phospholipid bilayers? - ANSWERphospholipids have
hydrophilic head and hydrophobic tail, hydrophobic face inside of cell making 2
layers
what is meant by fluid mosaic? - ANSWERMosaic of proteins drifting laterally in fluid
bilayer of phospholipids
how are membranes adjusted for different temperatures? - ANSWERmembrane
fluidity adjusted by changing the ratio of unsaturated to saturated fatty acids
how do the relative amounts of saturated and unsaturated fats change? - ANSWERif
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? - ANSWERnot too solid, not too fluid
why is fluidity an important property? - ANSWERpreserves 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? -
ANSWERfound 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? - ANSWERsmall
nonpolar molecules, gases, steroid hormones, and water
what is simple diffusion? - ANSWERdown the concentration gradient; does not
require supplied energy; does not use a carrier molecule
what is facilitated diffusion? - ANSWERdown the concentration gradient; employs
carrier molecule; does not require supplied energy
what is active transport? - ANSWERwork must me done; must use supplied energy;
employs carrier molecule
for which transport processes are carrier molecules involved? - ANSWERfacilitated
diffusion and active transport
which transport processes require the input of additional energy? - ANSWERactive
transport
what is a semi-permeable barrier? - ANSWERonly some types of molecules pass
through
, when equilibrium is reached in diffusion: does movement of molecules stop? -
ANSWERno
when equilibrium is reached in diffusion: does the net movement of molecules stop?
- ANSWERyes
what is meant by hypertonic? - ANSWERlower water potential; more solutes
dissolved; tend to gain water via osmosis
what is meant by hypertonic? - ANSWERhigher water potential; fewer solutes
dissolved; will tend to lose water via osmosis
isotonic - ANSWERequivalent water potential; equal number of solutes; no note
movement of water
in which direction does water flow? - ANSWERosmosis and the direction of net water
movement
what are aquaporins? - ANSWERchannel proteins which facilitate water diffusion
through the membrane
marine bony fish are...? - ANSWERhypotonic to seawater
how do enzymes work? - ANSWERthey position the reactants in a conformation
more favorable for the chemical reaction to occur
what aspects of the energetics do enzymes change? - ANSWERenzymes lower
activation energy barrier ΔG⧧
what aspects of energetics do enzymes not affect? - ANSWERthey do not reverse
an energetically unfavorable reactions; they do not make a reaction go uphill
how are substrates lured into the active site? - ANSWERpositively charged arginine
sidechain lures the negatively charged substrate into the active site
Why is there an upper limit? - ANSWERIt is energetically too costly to make
biological molecules that breakdown that quickly
You can't build them faster than they are broken down
Enzyme homologs - what are they? - ANSWERComparable enzymes from different
organisms
Enzyme homologs from cold- and warm-adapted species - how do they differ in
order to adapt to the different thermal energy in their environments to maintain
adequate catalytic rates? - ANSWERAt their respected temperatures the enzymes
catalyze the reaction at similar rates
At a common temperature, the enzyme from cold-adapted species converts
substrate to product a faster rate
ANSWERS 100% CORRECT!!
why are membranes called phospholipid bilayers? - ANSWERphospholipids have
hydrophilic head and hydrophobic tail, hydrophobic face inside of cell making 2
layers
what is meant by fluid mosaic? - ANSWERMosaic of proteins drifting laterally in fluid
bilayer of phospholipids
how are membranes adjusted for different temperatures? - ANSWERmembrane
fluidity adjusted by changing the ratio of unsaturated to saturated fatty acids
how do the relative amounts of saturated and unsaturated fats change? - ANSWERif
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? - ANSWERnot too solid, not too fluid
why is fluidity an important property? - ANSWERpreserves 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? -
ANSWERfound 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? - ANSWERsmall
nonpolar molecules, gases, steroid hormones, and water
what is simple diffusion? - ANSWERdown the concentration gradient; does not
require supplied energy; does not use a carrier molecule
what is facilitated diffusion? - ANSWERdown the concentration gradient; employs
carrier molecule; does not require supplied energy
what is active transport? - ANSWERwork must me done; must use supplied energy;
employs carrier molecule
for which transport processes are carrier molecules involved? - ANSWERfacilitated
diffusion and active transport
which transport processes require the input of additional energy? - ANSWERactive
transport
what is a semi-permeable barrier? - ANSWERonly some types of molecules pass
through
, when equilibrium is reached in diffusion: does movement of molecules stop? -
ANSWERno
when equilibrium is reached in diffusion: does the net movement of molecules stop?
- ANSWERyes
what is meant by hypertonic? - ANSWERlower water potential; more solutes
dissolved; tend to gain water via osmosis
what is meant by hypertonic? - ANSWERhigher water potential; fewer solutes
dissolved; will tend to lose water via osmosis
isotonic - ANSWERequivalent water potential; equal number of solutes; no note
movement of water
in which direction does water flow? - ANSWERosmosis and the direction of net water
movement
what are aquaporins? - ANSWERchannel proteins which facilitate water diffusion
through the membrane
marine bony fish are...? - ANSWERhypotonic to seawater
how do enzymes work? - ANSWERthey position the reactants in a conformation
more favorable for the chemical reaction to occur
what aspects of the energetics do enzymes change? - ANSWERenzymes lower
activation energy barrier ΔG⧧
what aspects of energetics do enzymes not affect? - ANSWERthey do not reverse
an energetically unfavorable reactions; they do not make a reaction go uphill
how are substrates lured into the active site? - ANSWERpositively charged arginine
sidechain lures the negatively charged substrate into the active site
Why is there an upper limit? - ANSWERIt is energetically too costly to make
biological molecules that breakdown that quickly
You can't build them faster than they are broken down
Enzyme homologs - what are they? - ANSWERComparable enzymes from different
organisms
Enzyme homologs from cold- and warm-adapted species - how do they differ in
order to adapt to the different thermal energy in their environments to maintain
adequate catalytic rates? - ANSWERAt their respected temperatures the enzymes
catalyze the reaction at similar rates
At a common temperature, the enzyme from cold-adapted species converts
substrate to product a faster rate
