Exam 3 Study

What is in a plasma membrane (6 components)

phospholipids, peripheral proteins, integral proteins, glycolipids, glycoproteins, cholesterol

What is the function of phospholipids in a plasma membrane

selectively permeable bilayer, amphipathic fluid movement

What is the function of peripheral proteins in a plasma membrane

maintaining cell structure, and signaling, transportation

What is the function of integral proteins in a plasma membrane

transport, anchoring the cell, acting as enzymes

what is the function of glycolipids in a plasma membrane

cell recognition, structural anchors

what is the function of glycoproteins in a plasma membrane (list 4)

cell-cell recognition, transport, enzymatic activity, intercellular joining, signal transduction

what is the function of cholesterol in a plasma membrane

maintaining fluidity, too cold=ensures looseness, too hot=ensures not too much liquidity

describe characteristics of a fluid mosaic model

mosaic of proteins floating in a sea of phospholipids, constant side to side movement, selectively permeable

what happens in a cell membrane if it gets too hot

increased kinetic energy of phospholipids makes them further apart, may lead to leakage

what happens in a cell membrane if it gets too cold

phospholipids lose fluidity and pack too tightly together, rigid

define passive transport

no energy input required for molecules to cross membrane (high % to low %)

define active transport

energy input required for molecules to cross membrane (low % to high %)

define diffusion

passive movement of molecules from high concentration to low concentration

define osmosis

spontaneous, passive transport of water across a cell membrane

define hypotonic

lower concentration of solutes outside of the cell than in

define hypertonic

higher concentration of solutes outside of the cell

define isotonic

same concentration of solutes outside and in

what factors affect the rate of diffusion of a substance

concentration gradient, temperature, size of molecule

explain simple diffusion

passing of small/nonpolar molecules from high to low concentration

give an example of simple diffusion

oxygen into the bloodstream, spraying perfume

explain osmosis

the passive transport of water across a membrane

what is turgor pressure

the water pressure inside a cell that pushes membrane against cell wal

explain facilitated diffusion

the type of passive transport where larger/polar molecules pass with no energy input, but the use of transport proteins

what is a membrane potential

the difference in potential inside and outside of a cell

give two ways a gated channel protein functions

a ligand can trigger the opening/closing, or it can be electrical like with neurons

describe how a carrier protein channel functions

a substrate bonds to the active site which triggers a change in shape

what does it mean for a carrier protein to be saturated

a saturated carrier protein means all of its available active sites are occupied

explain primary active transport

uses usually ATP hydrolysis to pump molecules against their concentration gradient

give an example of primary active transport

sodium/potassium pump and proton pump

explain co-transport

when one transport protein moves two or more molecules in the same direction at the same time

give an example of co-transport

sodium-glucose symporter in the small intestine

what are the types of endocytosis

phagocytosis, pinocytosis, receptor-mediated endocytosis

describe phagocytosis

cell engulfs something until it merges with a lysosome

describe pinocytosis

cell drinking/ coat proteins on inside of plasma membrane pull inward creating a vesicle

describe receptor-mediated endocytosis

cell engulfs only certain molecules, coat proteins attached to extracellular receptors that are specific to certain molecules, humans use to engulf cholesterol, hormones, vitamins

how does receptor-mediated endocytosis differ from the other types of endocytosis

it is selective/ has the ability to be specific

explain exocytosis

vesicle membrane becomes part of cell membrane, empties contents outside of the cell

define potential energy

energy that is stored by maintaining position or chemical bonds

define kinetic energy

the energy of movement by change, heat, motion, sound

define catabolism

breaking larger molecules into smaller, releases energy/ positive

define anabolism

builds smaller into larger, takes energy/ negative

define chemical energy

potential energy stored within the bonds of a atom or molecule

define an exergonic reaction

those that release energy, spontaneous because low energy states are preferred

define an endergonic reaction

requires the input of energy/ deltaG is positive

how are anabolism and catabolism linked

energy coupling

what is the first law of thermodynamics

energy cannot be created nor destroyed, only transferred or transformed

what is the second law of thermodynamics

transforming energy increases the disorder/ releases heat into the universe

what is entropy

the amount of chaos or disorder in a system

how is entropy related to the second law of thermodynamics

transformation of energy increases chaos/ increases entropy

describe a ribozyme

a RNA molecule capable of acting as a catalyst

what is an energy barrier

the minimum amount of energy required for a reaction to take place

define transition state

the point where there is enough energy to complete the reaction/ point of no return

define activation energy

input of energy for the reaction to proceed

define induced fit

enzyme changes shape and closes around the substrate

define cofactor

inorganic, nonprotein molecules required for some enzymes to function

define coenzyme

organic, nonprotein molecules required for some enzymes to function

define rate of reaction

the speed at which a chemical reaction proceeds

what does an enzyme do to a reaction

lowers the activation energy required

give 4 ways an enzyme can lower activation energy

holding molecule in optimal position, increase tension/bend bonds, provide favorable environment for reaction to take place, make molecules unstable/want to break

define metabolic pathway

a linked series of chemical reactions

define irreversible inhibition

occurs when a molecule permanently binds to an enzyme (covalently) disablei

define reversible inhibition

define allosteric regulation

when a molecule binds to an enzyme somewhere other than its active site, turning its function on or off

define feedback inhibition

when the end product of a metabolic pathway binds to an enzyme that acts earlier in the pathway, stopping its activity

what are the two types of reversible inhibition

competitive and non-competitive

define competitive inhibition

inhibitory molecules bind to an enzymes active site, blocking the usual substrate

define non-competitive inhibition

inhibitory molecules bind to an enzyme somewhere other than its active site

why is ATP used as the currency of the cell

it is immediate energy and non-specific to any cellular process

what is OIL RIG

oxidation is loss, reduction is gain

define redcution

reduced atom/molecule gains electrons/ gains potential energy

define oxidation

atom/molecule being oxidized loses electrons/ loses potential energy

define redox

oxygen-reduction reaction- transfers electrons from one atom or molecule to another

define substrate level phosphorylation

some enzymes bond to phosphorylated intermediates and ADP, only small amount of ATP generated

what are the two steps of oxidative phosphorylation

Electron Transport Chain and Chemiosmosis

what is the electron transport chain

cell using redox reaction to power active transport of H+ up its concentration gradient

what is chemiosmosis

once an imbalance is achieved, H+ flows down its concentration gradient, ATP synthase (membrane bound protein) captures the energy

define proton motive force

the energy stored in a gradient of H+ across a membrane, how bad they want to go back

what does NAD stand for

nicotinamide adenine dinucleotide

what forms can NAD exist in

NADH (reduced form) and NAD+ (oxidized form)

what does FAD stand for

flavin adenine dinucleotide

where is cellular respiration can FAD be found

FAD is found during oxidative phosphorylation