Cell Membrane and Cell Transport

passive transport

does not require energy because it moves with the concentration gradient, (high to low)

active transport

requires energy, goes from low to high concentration so against the concentration gradient

diffusion

molecules move from more (high) to less(low) concentrated area until equilibirium is reached, small nonpolar molecules

osmosis

diffusion of water through a selectivly permeable membrane

osmotic pressure

pressure due to water

facilitated diffusion

diffusion with the help of carrier/channel proteins aka selective transport, hydrophilic and ions t pass through membrane

ex of passive transport

diffusion, osmosis, facilitated diffusion (selective transport)

ex of active transport

sodium pottasium pump, proton pump, exocytosis, endocytosis

exocytosis

large molecules transported out, vesicle fuses with cell membrane

endocytosis

large molecules transported in, vesicle forms from cell membrane

invaginating

the cell membane pushing into the cell to accept the molecule (in exocytosis and endocytosis)

pinocytosis

cell drinking, molecules takeninto cell wall with large amounts of liquid with it

phagocytosis

solid molecules taken in by cell (bacteria engulfed by white blood cells)

receptor mediated endocytosis

receptor proteins figure out the need the molecules floating around and they attach to the recpetor protein and are brought intot he cell through endocytosis

passive transport can be

both directions in and out of the cell

active transport is goes only 1 way because

cells smart why spend energy bringing it in or pushing it out j to do the opposite and spend more energy

voltage channel proteins

sensing electrical signals, how nerve cells communicate

chemical channel proteins

sensing chemical signals, ex. liver cells sensing blood glucoe levels high so they open channel proteins

cell size doesnt change bc of movement of solute but because of

movement of water

water always moves

high water to low water

low solute to high solute

$100(atm)→$1000(bank)→$50000(savings)

atp→carbs→lipids

the 1-2 phosphate bond is

the highest energy bond so it breaks causing atp to change to adp when energy is needed

atp and adp have a

reversible process changing back and forth based on whats needed

enzymes are

biocatalysts

endergonic

energy being absorbed from enviornment, (endothermic with thermal energy)

exergonic

energy being released (exothermic with thermal energy)

subrate saturation is where

the reaction time plateus and no longer increases because the solution is saturated with subrates and adding more will no longer increase reaction rate

catalytic site is also

the active site

allosteric enzymes

have an active site and then an allosteric site where teh product of the active site fits and then after the reaction happens in the allosteric sit ehte active site changes shape so that the enzyme is inactive, when all of the product is used up the enzyme becomes active again and changes the shape of the active site back to what the subrate fits into

biochemical pathway

a→b

b→c

c→d

d→e

if b→c stops working them the chain of reactions stops happening and the biochem pathway goes away and there will be excess b but not c,d, or e

b,c,d are intermediates while a is the reactant and e is the product

multienzyme complex

multiple enzymes working on biochem pathway

cooperativity-process

1 ezyme with mulitple active sites that does the entire biochem pathway

contratransport

secondary active transport, uses energy from electrochemical gradient, transport 2 diff ions across membrane through proteins

symport

2 diff ions same direction

antiport

2 diff ions diff directions

membranes can become ______________ from ions

polarized

electrochemical gradient

type of concentration gradient, electrical difference across membrane

electrical potential

electrical potential diff(voltage) across membrane

osmolarity

total solute concentration

aquaporins

help large quantities of water move via aquaporins

tonicity

mesaurement of the relative concentrations of solute b/w 2 solutions (inside and outside of cell)

hypertonic

more solute less solvent

hypotonic

less solute more solvent

enviornmental hypertonicity

cell shrinks

enviornemental hypotonicity

cell swell

lyses

when cell bursts

water potential

tendency water to move through osmosis

small amounts of polar molecules can

pass through the membrane

endosymbiosis

free living aerobic prokaryote engulfed by anaerobic cell through endocytosis but it didnt get ingested and it eventually lost its independence, origin of mitocondria and chloroplast, they both have double membrane and their own copies of dna and ribosomes

origin of er and nuclues

plasma membrane folding

activation energy

intial starting energy, lowered by enzymes

net releases

typically require less activation energy

net absorption

typically require more

conformational shape

tertiary shape

why does reaction rate increase

* inreased speed of molecular movement
* increased frequency of enzyme subtrate collisions

decrease in temperature does not denature but instead

decreases reaction time bc less substrate enzymes collisions

enzymes do denature due to increase or decrease in

pH

why does the reaction rate plateu once the concentration is saturated with substrates

themore subrate the more product and once there isalot of product it takes up space so lower chance of enzyme substrate collion

competetive inhibitor

molecules can bind reversibly or irrversibly to the active site of the enzymes, competes with the normal substrate for enzymes active site

what happens if the competetive inhibitors outnumber the substrates

the reactions are slow

if inhibitor binding is irreversile then

the enzymes function is prevented

noncompetetive inhibitors

bind to allosteric site, not active site which causes the enzyme to change shape of the original active site preventing enzyme function

autotrophs capture energy from

physical or chemical sources that are changed into somthing usable

2nd law of thermodynamics

* every energy transfer increases disorder
* living cells are never at equilibrium there is always a constant flow of materials in and out
* cells manage energy resources by energy coupling, energy releasing processes drive energy storing processes

cofactors

inorganic nonprotein helpers (Fe, Zn, Cu)

coenzymes

organic helpers (vitamins)

first law of thermodymanics

energy can neither be created nor destroyed only changed

if the cell needs some of the sodium it pushed out using active transport and a sodium pottassium pump then it will

use couled channel proteins to bring it back in using facilited diffusion

chemiosmosis

chem energy from transport, cell wont spend energy to bring back protons diffuse back in with atp

flaccid

plant cell in isotonic solution

turgid

plant cell in hypotonic solution but doesnt lyse or burst bc of cell wall (turgor pressure)

cells are usually in ________ solute of NaCl so thats whats pumped into u when ur dehyrdated

0\.851, (saline)

root pressure

how water is forced up xylem

transpiration

water loss through xylem

trasnlocation

transport of sugar through the phloem

guttation

small drops of sap (water and minerals) ooze from the leaf tip due to root pressure

cuticle

helps prevent water loss, small hair on leaf and leaf surface

what controls the opening of the stoma

guard cells

water moves from ________ psi to

high, low psi

solute ___________ psi

decreases

pressure _____________ psi

increases