Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
59 Cards in this Set
- Front
- Back
|
Energy
|
•ability to do work |
|
|
Potential energy
|
•stored energy available to do work |
|
|
Kinetic energy
|
•energy being used to do work/energyin motion •Some examples: movement, heat,light, sound |
|
|
•Firstlaw of thermodynamics |
•Energy is neither created nor destroyed, but can betransferred from one form to another |
|
|
Laws of thermodynamic |
•Inthe introductory activity chemical energy in our bodies was changed tomechanical energy in our arms. |
|
|
FirstLaw |
•Apractical ecological consequence of this law is that all living things musthave a source of energy. •Theultimate source of energy for most living things is the sun. |
|
|
-Secondlaw of thermodynamics |
-allenergy transformations are inefficient |
|
|
Entropy
|
(ameasure of dispersal of energy in asystem) increases spontaneously |
|
|
SecondLaw of Thermodynamics
|
•statesthat at every energy transfer someportion of the available energy is degraded to heat which moves to coolerobjects. |
|
|
energy pone way flow
|
•The total amount of energyavailable in the universe to do work is always decreasing •Each time energy is transferred, someenergy escapes as heat (not useful for doing work) • •On Earth, energy flows from thesun, through producers, then consumers •Living things need a constant input ofenergy |
|
|
•ChemicalReaction |
•A chemical change that occurs when atoms,ions, or molecules interact |
|
|
Reactant
|
•Atoms, ions, or molecules that enter areaction |
|
|
•Product |
•Atoms, ions, or molecules remaining atthe end of a reaction |
|
|
Chemical reactions
|
•influencedby: Øtemperature Øconcentrationof reactants and products |
|
|
Endergonic
|
•(“energyin”) Reactions •Reactions that require a net input ofenergy |
|
|
Exergonic
|
•(“energyout”) Reactions •Reactions that end with a net release ofenergy |
|
|
•Activationenergy |
•The minimum amount of energy needed toget a reaction started •Some reactions require a lot ofactivation energy, others do not |
|
|
energy in , energy out
|
•Cellsstore free energy by running endergonic reactions that build organic compounds •Example:photosynthesis • •Cellsharvest free energy by running exergonic reactions that break the bonds oforganic compounds •Example:aerobicrespiration |
|
|
Enzyme
|
•In a process called catalysis, an enzyme makes a specificreaction occur much faster than it would on its own |
|
|
Substrate
|
•The specific reactant acted upon by anenzyme |
|
|
•Activesites |
•Locations on the enzyme molecule wheresubstrates bind and reactions proceed •Complementary in shape, size, polarityand charge to the substrate |
|
|
Metabolism
|
is the total of all chemical reactionscarried out by an organism
|
|
|
anabolism
|
vreactions that expend energy to make ortransform chemical bonds |
|
|
catabolism
|
reactions that harvest energy whenchemical bonds are broken
|
|
|
metabolicpathway
|
•is any series of enzyme-mediatedreactions by which a cell builds, rearranges, or breaks down an organicsubstance |
|
|
control over metabolism
|
•Concentrations of reactants orproducts can make reactions proceed forward or backward • •Feedback mechanisms can adjustenzyme production, or activate or inhibit enzymes |
|
|
•Oxidation-reductionreactions (pairedreactions) |
•A molecule that gives up electrons isoxidized •A molecule that accepts electrons isreduced •Coenzymes can accept molecules in redoxreactions (also called electron transfers) |
|
|
Cofactors
|
•Atoms or molecules (other than proteins)that are necessary for enzyme function •Example: Iron atoms in catalase • |
|
|
Coenzymes
|
•Organic cofactors such as vitamins •May become modified during a reaction |
|
|
ATP
|
•A nucleotide (adenine) with ribose andwith three phosphate groups •Transfers a phosphate group and energy toother molecules |
|
|
Phosphorylation
|
•A phosphate-group transfer ADP binds phosphate in anendergonic reaction to replenish ATP |
|
|
membrane lipids
|
•Phospholipid molecules in theplasma membrane have two parts •Hydrophilic heads interact with watermolecules •Hydrophobic tails interact with eachother, forming a barrier to hydrophilic molecules • |
|
|
•Fluidmosaic model |
•Describes the organization of cellmembranes •Phospholipids drift and move like a fluid •The bilayer is a mosaic mixture ofphospholipids, steroids, proteins, and other molecules |
|
|
Membrane proteins |
•Cell membrane function begins withthe many proteins associated with the lipid bilayer • •Peripheral membrane proteinstemporarily attach to the lipid bilayer’ssurfaces by interactions with lipids or other proteins • •Integral membrane proteinspermanently attach to a bilayer • |
|
|
TransportProteins |
•createpassageways through which water-soluble molecules and ions pass into or out ofcell |
|
|
Enzymes
|
•speedup a chemical reaction |
|
|
RecognitionProteins-
|
•carbohydratesattached to cell surface proteins -help the body recognize its own cells |
|
|
Adhesionproteins-
|
enablecells to stick to one another
|
|
|
Receptorproteins-
|
bindmolecules outside the cell and triggering a reaction inside a cell
|
|
|
Passivetransport
|
Passivetransport
|
|
|
Diffusion
|
•The net movement of molecules down aconcentration gradient •Moves substances into, through, and outof cells •A substance diffuses in a direction setby its own concentration gradient, not by the gradients of other solutes aroundit |
|
|
•Simple diffusion |
•Form of passive transport not using acarrier protein |
|
|
Concentration
|
•The number of molecules (or ions) ofsubstance per unit volume of fluid |
|
|
•Concentrationgradient |
•The difference in concentration betweentwo adjacent regions •Molecules move from a region of higherconcentration to one of lower concentration |
|
|
Tonicity
|
•The relative concentrations of solutes intwo fluids separated by a selectively permeable membrane- ability of a cellmembrane to control which substances and how much of them enter or leave thecell |
|
|
hypotonic
|
For two fluids separated by asemipermeable membrane, the one with lower solute concentration
|
|
|
hypertonic
|
For two fluids separated by asemipermeable membrane, the one with higher solute concentration
|
|
|
Isotonic
|
•fluids have the same soluteconcentration |
|
|
Osmosis
|
•The movement of water down itsconcentration gradient – through a selectively permeable membrane from a regionof lower solute concentration to a region of higher solute concentration |
|
|
Turgor
|
•The pressure exerted by a volume of fluidagainst a surrounding structure (membrane, tube, or cell wall) which resistsvolume change |
|
|
•Osmoticpressure |
•The amount of turgor that stops osmosis |
|
|
•Facilitated diffusion |
•Requires no energy input •A passive transport protein allows aspecific solute (such as glucose) to follow its concentration gradient across amembrane •A gated passive transporter changes shapewhen a specific molecule binds to it |
|
|
•Activetransport |
•Requires energy input (usually ATP) •Moves a solute against its concentrationgradient, to the concentrated side of the membrane |
|
|
•Cotransporter |
•An active transport protein that movestwo substances across a membrane at the same time •Example: The sodium-potassium pump moves Na+ out of the cell and K+ into the cell |
|
|
•Exocytosis |
•The fusion of a vesicle with the cellmembrane, releasing its contents to the surroundings |
|
|
•Endocytosis |
•The formation of a vesicle from cellmembrane, enclosing materials near the cell surface and bringing them into thecell |
|
|
•Receptor-mediated endocytosis |
•Specific molecules bind to surfacereceptors, which are then enclosed in an endocytic vesicle |
|
|
•Phagocytosis |
•Larger target particles such as microbesor cellular debris are engulfed by pseudopods which merge as a vesicle, whichfuses with a lysosome in the cell |
|
|
Pinocytosis
|
•Aless selective endocytic pathway thatbrings materials in bulk into the cell |
