BIO 101 (Chapter 4 Energy & Metabolism) 9/12/17 TEST 2
For metabolism to work, a cell must keep its internal composition stable -even when conditions outside are greatly different
(aka against a concentration gradient)
Why/how do plant cells wilt? Why are these cells or plants turgid under normal soil moisture conditions?
-- plant cells wilt bc the loss of turgid pressure where your losing water to the extracellular area -- normal moisture conditions are equal you dont have anything moving in or out of the cell
phosphate-group(phosphorylation) transfers to and from
ATP couple energy releasing reactions with energy requiring ones.
First law of thermodynamics
Energy cannot be created or destroyed▻ It can be converted from one form to another and thus transferred between objects or systems
Second law of thermodynamics
Energy tends to disperse spontaneously▻ A small amount disperses at each energy transfer, usually in the form of heat [incandescent light bulb -5-10% efficient; CFL -50-75%; internal combustion engine -20%]
tonicity
a measure of osmotic pressure gradient, as defined by the water potential of two solutions separated by a semipermeable membrane. aka... determines the direction and extent of diffusion.
a transport protein requires ATP to pump sodium ions across a membrane this is a case of
active transport
Selective Permeability (i.e.: Semipermeable membranes)
allows some substances through but not others.
concentration gradient
basis of diffusion
Regulatory molecules affect an enzyme by
binding directly to its active site; or elsewhere on the enzyme.
What is the most serious drug problems on college campuses?
binge drinking
Alcohol Dehydrogenase (ADH)
breaks down ethanol and other toxic compounds
A metabolic pathway ___
builds or breaks down molecules generates heat can include an elctron transfer chain
energy
capacity to do work
exocytosis
cell EXPELS a vesicles contents to extracellular fluid by meging the vesicles with the plasma membrane
phagocytosis
cell eating (white blood cells)
isotonic
cell remains the same it has the same concentration inside and out
What happens to a cell in a hypertonic solution
cells shrink higher concentration inside
What happens to a cell in a Hypotonic solution
cells swells higher concentration outside
What are the five factors that effect diffusion rate?
concentration temperature size charge pressure
passive transport
concentration gradient drives a solute across a cell membrane through a transport protien does NOT requrie energry ie: Glucose transporters.
What happens after the break down of ethanol occurs?
damage to liver cells, leading to alcoholic hepatitis or cirrhosis of the liver
when hydrogen bonds are broken it begins to
denature it... and stop working
If you immerse a human red blood cell in a hypotonic solution water will _____
diffuse into the cell
Osmosis (specialized just for water)
diffusion of water...... across a selectively permeable membrane between 2 fluids that are not isotonic
vesicles are part of
endo exo phago cytosis
What things can diffuse across a lipid bilayer??
gas, water, and small non polar molecules
Electron transfer chains allow cells to
harvest energy in manageable incremenets An array of membrane-bound enzymes and other molecules that accept and give up electrons in sequence
Living things maintain their organization by
harvesting energy from someplace else
net loss (adding more energy to make the bond happen)
input is higher
net gain (the process will give off energry)
input less energy
what are all the kinds of energy?
light chemical kinetic thermal
Cells store and retrieve energy by
making and breaking chemical bonds in metabolic reactions
feedback inhibition
mechanism by which a change that results from some activity decreases or stops that activity
Product
molecule remaining at the end of a reaction
reactant
molecule that enters a reaction(what you start with)
coenzyme
organic cofactor that make reactions more effective. can be modified by a reaction
Tugor (specifically in plants) counters osmosis
pressure that a fluid exerts against a wall, membrane, etc... osmosis contiunes until two fluids are isotonic
endocytosis
process by which a cell takes IN a small amount of extracellular fuild by a ballooning inward of its cellular membrane (human blood) (Leukocytes)
reaction
process of chemical change
____ are always changed by participating in a reaction
reactants
If we liken a reaction to an energy hill then a reaction that _____ is an uphill run
requires energy
Metabolic pathway
series of enzyme mediate reactions by which cells build, remodel, or breakdown an organic molecule
Diffusion
spontaneous spreading of molecules or ions through a liquid or a gas High to low concentration
_____ is life primary source of energy
sunlight
enzymes are influenced by
temp pH salt concentration
An environment factor that directly influences enzyme function is
temperature
Chemical bonds hold energy
the amount depends on which elements take part in the bond
ATP (adenosine triphosphate)
the main energy carrier between reaction sites in cells. (breaking off or gaining of phosphate groups)
activation energry
the minimum amount of energy required to start a reaction
Active transport
transport protein uses energy (ATP) to pump a solute across a cell membrane against its concentration gradient ie: calcium pump
How do other molecules and ions cross the bilayer?
transport proteins
fluid pressure against a wall or cell membrane is called
turgor
When fluids on either side of a selectively permeable membrane differ in solute concentration...
water diffuses across the membrane
An enzyme's particular substrate(s) bind at its activation site
▻Substrate= a reactant molecule that is specifically acted upon by an enzyme ▻Active Site = Pocket in an enzyme where substrates bind and a reaction occurs