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