Cell Biology Ch. 8

examples of gas solutes

O2, CO2, N2

examples of ionic solutes

Na+, K+, Ca2+, Cl-, H-

examples of small molecule solutes

amino acids, glucose, metabolites

most solutes are (__) in concentration inside cell compared to outside. why?

higher / required for life

list all types of transport

active (primary [ATP-driven and light-driven] and secondary [antiport and symport]) and passive (simple diffusion, facilitated diffusion, and osmosis)

which forms of transport do/don’t require transport protein

all active and fac. diffusion do require / osmosis and simple diffusion do not

if solutes move from high to low concentration they are moving how with gradient?

down/with

if solutes move from low to higher concentration, they are moving how with gradient?

up/against

limit to transport rate

saturation

what kinds of transport have a saturation limit

those that require membrane proteins

(__) inhibition can affect transport

competitive

does passive transport require metabolic energy? what is delta G? moves how with concentration gradient? saturation limits? competitive inhibition? membrane protein?

no / negative / with or down / some / some / some

does active transport require metabolic energy? what is delta G? moves how with concentration gradient? saturation limits? competitive inhibition? membrane protein?

yes / positive / against or up / yes / yes / yes

what kind of solute molecules move by active transport

large polar molecules like amino acids, glycerol, glucose, and ions

what kind of solute molecules move by passive transport

polar molecules like water, glycerol, gluocse and nonpolar molecules like o2 and CO2 and ions

unequal distribution of a solute across a membrane or in a space

gradient

two types of gradients

concentration and electrochemical

concentration gradient is based on unequal distribution of (__) solutes

neutrally charged

electrochemical gradient is based on unequal distribution of (__) solutes

charged

the specific unequal distribution of charge is

membrane potential Vm

t or f: charge and chemical gradient can oppose each other

t

what are the concentrations of Na, K, Mg, Ca, and Cl inside vs. outside cell

Na+ higher outside / K+ higher inside / Mg2+ higher outside / Ca2+ higher outside and inside ER / Cl- higher outside

ion concentrations are maintained by (__) and important for?

cells / transport and nerve signaling

simple diffusion uses what kind of solutes? moves how with concentration gradient? metabolic energy required? so delta G is? membrane protein required? saturation limits? competitive inhibition?

nonpolar (O2 and CO2) / with or down / no / negative / no / no / no

simple diffusion always moves? until it reaches (__) (__). how does it affect entropy?

towards equilibrium / dynamic equilibrium / increases

facilitated diffusion moves what kind of solutes? moves how with concentration gradient? metabolic energy required? so delta G is? membrane protein? saturation limits? competitive inhibition?

polar molecules like water, glycerol, and glucose and ions / with or down / no / negative / yes / yes / possible

can polar molecules like water simply diffuse? can ions?

yes but slowly / no

movement of water in response to differences in solute concentration

osmosis

low vs. high osmolarity and how water flows

flows low to high. low osmolarity is low solute and high water and high osmolarity is high solute and low water

the solution with lower osmolarity is hypo or hypertonic?

hypotonic

(__) solution has higher solute concentration and lower water concentration compared to cell. causes animal cell to (__) and plant cell to (__)

hypertonic / shrivel / plasmolyze

(__) solution has lower solute concentration and higher water concentration compared to cell. causes animal cell to (__) and plant cell to (__)

hypotonic / swell and then lyses / become turgid

(__) solution has equal solute concentration and equal water concentration compared to cell. causes plant cell to be (__)

isotonic / flaccid

what osmolarity of solution do animal and plant cells like to be

animal like isotonic but plant cells like hypotonic

rank the following from most able to cross lipid bilayer to least able to cross

1. ions (H+, Cl-)

2. H2O, urea, glycerol

3. O2, CO2, N2, steroid, hormones

4. glucose, sucrose

3, 2, 4, 1

rank the following from most able to cross lipid bilayer to least able to cross

1. hydrophobic molecules

2. large uncharged polar molecules

3. ions

4. small uncharged polar molecules

1, 4, 2, 3

permeability (__) with solute size. (__) required to move larger molecules. membranes are (__) to most polar molecules. membranes are simply (__) to charge

decreases / facilitated diffusion / impermeable / impermeable

rate of transport equation

V_inward = PΔ[S] where p is permeability coefficient and delta S is solute concentration outside minus inside (units are moles/second-cm²)

rate of transport is directly (__) to concentration difference across the membrane

proportional

facilitated diffusion creates a (__) graph

hyperbolic

simple diffusion creates a (__) graph

linear

facilitated diffusion is mediated by what 2 types of transport proteins

carriers and channels

t or f: facilitated diffusion has a maximum transport rate

t

carrier proteins follow (__) model which is (__)

alternating conformation model / reversible

solute binding site open and available on one side of the membrane

conformation 1

solute binding site open to other side of membrane, triggering solute release

conformation 2

carrier proteins follow enzyme (__). referred to as (__) and can become (__). operate at (__) rate. specific (__) and subject to (__) inhibition

kinetics / permeases / saturated / maximum / binding / competitive

what are the 2 types of carrier proteins and explain

uniport move one solute / cotransport is moving 2 solutes

2 types of cotransport carrier proteins and explain

symport move solutes in same direction while antiport moves them opposite

is cotransport passive or active?

active

example of (__) transport mechanism

1. glucose binds to a (__) that has binding site open to outside (__ conformation)

2. glucose binding causes the transporter to shift to (__) conformation with binding site open to (__) of cell

3. glucose is released to cell interior, initiating second (__) change in (__)

4. loss of bound glucose causes GLUT1 to return to (__) conformation, ready for further transport

5. (__) converts glucose to (__) inside cell to help keep glucose concentration inside cell (__) because GLUT1 (___) bind to G6P. reversible process if inhibited by related (__)

uniport / GLUT1 transporter protein / T1 / T2 / inside / conformational / GLUT1 / T1 / hexokinase / G6P / lower / doesn’t / monosaccharides

anion exchanger is an example of (___) cotransport in red blood cell. conformation 1 binds (__) outside of cell and releases (__). conformation 2 binds (__) inside cell and releases (__). CO2 is converted to (__) then (__). equation shifts in (__)

antiporter / Cl- / HCO3- / HCO3- / Cl- / carbonic acid / bicarbonate / lungs

types of channels

ion, porins, aquaporins

channel on outer membrane of mitochondria, chloroplasts, and bacteria, nuclear pores

nonspecific

ion channels and aquaporins are what type of channel

specific

ion channels are specific for one or two ions based on

charge and size

ion channels that respond to changes in chemical binding

ligand-gated

ion channel that responds to changes in local membrane potential

voltage-gated

ion channel that responds to physical movement

mechanically-gated (mechanosensitive)

why are too large ion channels not good

can’t strip away hydration shell

ion channels are sensitive to charge, determined by (__) that line (_) channel

amino acids / hydrophilic

a (__) charged ion requires negatively-charged (full or partial) amino acid R groups in channel

positive

a (__) charged ion requires positively-charged (full or partial) amino acid R groups in channel

negative

channel found in the outer membranes of mitochondria and chloroplasts and bacteria

porins

are porins very specific? limited by? typically?

no / size / beta barrels

can water be actively moved? how do you move water against its gradient?

no / move sodium and water follows

collective concentration of all solutes in solution

osmolarity

aquaporins are driven by (__). where is osmolarity higher in cell or outside?

osmolarity / higher inside cells

since active transport has a positive delta G, what needs to happen

has to be coupled with favorable reaction

active transport performs three functions:

1. allows acquisition of resources into cell, even when the concentration is (__) in the cell

2. allows for the (__) of various substances, even when concentration is (__) on the outside of the cell

3. allows cells to maintain (__) that are important for other transport activies

higher / removal / higher / ion concentration gradients

main tool cells use to mediate active transport

pumps

do active or passive transport exhibit directionality? what does this mean

active transport has directionality means only moves things in one direction while passive moves in both directions

what is the difference between primary and secondary active transport

primary or direct active transport consumes metabolic energy at the pump while secondary or indirection active transport does not (uses stored energy)

primary active transport is coupled to (__) chemical reaction which is (__). and coupled to (__) energy (plants/bacteria)

exergonic / ATP hydrolysis / light

what are the 4 types of primary active transport

P-type, V-type, F-type, and ABC-type

p-type pumps (__). become (__) during transport process. an example is (__)

ions / phosphorylated / sodium potassium pump

v-type pumps (__). phosphorylated? important for (__) to maintain pH for acidic hydrolases

protons / no / lysosomes

f-type forms (__) from (__) gradients through process of (__)

ATP / H+ / ATP synthase

ABC-type pumps (__). example is (___) which pumps out (__) drug

molecules other than ions / multidrug resistance transport protein / anticancer

secondary active transport is coupled to (__) (__) movement of another solute (usually a (__)). use (__) to drive solute transport

exergonic / inward / ion / ion gradient

(__) is a common cotransport ion in animal cells and (__) is a common cotransport ion in bacteria for secondary active transport

Na+ / H+

uses ATP to drive the movement of sodium and potassium against their gradients

sodium/potassium ATPase

how many sodium and potassium moved in/out cell by sodium potassium pump

3 sodium out and 2 potassium in

what are the E1 and E2 states of sodium potassium ATPase

E1: open to inside of cell, high affinity for sodium, low affinity for potassium

E2: open to outside of cell, high affinity for potassium, low affinity for sodium

steps of sodium potassium pump

1. open to inside cell. 3 sodium bind

2. phosphorylation happens, ADP leaves and P added

3. conformation change to get rid of sodium

4. pump open to outside. two potassium bind

5. dephosphorylation happens, P leaves

6. potassium is expelled and ATP rebinds

the sodium glucose pump is a (__) which does what type of transport?

symporter / secondary active

how are sodium and glucose moved in Na+/Glucose symporter? what is the delta G for these movements

2 sodium in and 1 glucose in / negative for sodium and positive for glucose

how does sodium/glucose symporter work?

1. open to outside.

2. 2 sodium bind cooperatively

3. glucose binds and conformation change

4. opens to inside

5. sodium released to inside and then driven to outside

6. loss of sodium is followed by glucose release

7. symporter opens back up to outside