AP Bio Unit 3 Study Guide

metabolism

metabolism

the totality of an organisms chemical reactions, consisting of catabolic and anabolic pathways which manage the material and energy resources of the organism

metabolic pathway

a series of chemical reactions that either builds a complex molecule (anabolic) or breaks down a complex molecule to simpler molecules (catabolic)

catabolic pathways

a pathway that releases energy by breaking down complex molecules to simpler molecules (energy released)

anabolic pathway

a pathway that consumes energy to synthesize a complex molecule from simpler molecules (energy is used)

bioenergetics

the overall flow and transformation of energy in an organism; the study of how energy flows through organisms

energy

the capacity to cause change, especially to do work

kinetic energy

the relative motion of objects (KE)

thermal energy

the random movements of atoms or molecules (TE)

Heat

TE in transfer from one body of matter to another

Potential energy

the energy that matter possesses as a result of its location or structure (PE)

chemical energy

energy available in molecules for release in a chemical reaction; form of PE

thermodynamics

study of transformations that could occur in a collection of matter

1st law of thermodynamics

principle of conservation of energy: energy can be transferred and transformed, but not created or destroyed

entropy

a measure of molecular disorder or randomness (the more random the greater the entropy)

2nd law of thermodynamics

principle stating that every energy transfer or transformation increases the entropy of the universe. usable forms of energy are at least partly converted to heat

spontaneous process

process that occurs without an overall input of energy; a process that is energetically favorable

non spontaneous process

process that on its own leads to a decrease in energy and will only happen if energy is supplied

free energy

portion of a biological systems energy that can perform work when temp and pressure are uniform throughout the system

what is the equation for the change in free energy

G(final state) - G(initial state)= the change in G (free energy)

exergonic reaction

a spontaneous chemical reaction in which there is a net release of free energy; the greater the decrease in free energy the greater amount of work can be done

endergonic reaction

a non spontaneous chemical reaction in which free energy is absorbed from the surroundings

chemical work

the pushing of endergonic runs that wouldn’t occur spontaneously

transport work

the pumping of substances across membrane against the direction of spontaneous movement

mechanical work

an example would be the beating of cilia, retraction of muscle cells

energy coupling

in cellular metabolism the use of energy released from an exergonic reaction is used to drive an endergonic rxn

phosphorylated intermediate

a molecule with a phosphate group covalently bonded to it, making it more reactive (less stable) than the unphosphorylated molecule

enzyme

macromolecule serving as a catalyst, a chemical agent that increases the rate of a rxn without being consumed by the rxn

activation energy

the amount of energy the reactants must absorb before a chemical rxn will start; AKA free energy of activation (energy needed to push “uphill” to then go “downhill”

transition state

when molecules have absorbed enough energy for the bonds to break, the reactancts are in this unstable situation

catalysis

a process by which a chemical agent called a catalyst selectively increases the rate of a rxn without being consumed by the rxn

substrate

the reactant on which the enzyme works

enzyme-substrate complex

a temporary complex formed when an enzyme binds to its substrate

active site

the specific region of an enzyme that binds the substrate that forms the pocket in which catalysis occurs

induced fit

caused by entry of the substrate, the change in shape of the active site of an enzyme so that is binds more snugly to the substrate

Substrates connected to enzyme?

held to the active site with hydrogen bonds and ionic bonds

saturation of enzymes

saturated as soon as the product exits an active site another substrate molecule enter

cofactor

any nonprotein molecule or ion that is required for the proper functioning of an enzyme. can be bound permanently to the active site or may bind loosely and reversibly along with the substrate during catalysis (inorganic)

coenzyme

an organic molecule serving as a cofactor. most vitamins function as coenzymes in metabolic reactions

competitive inhibitors

a substance that reduces the activity of an enzyme by entering the active site in place of a substrate whose structure it mimics

noncompetitive inhibitor

substance that reduces the activity of an enzyme by binding to a location remote to the active site, changing the enzymes shape so that the active site no longer effectively catalyzes the conversion of the substrate to the product

allosteric regulation

the binding of a regulatory molecule to a protein at one site that affects the fan of the protein at a different site

cooperativity

kind of allosteric regulation whereby a shape change in one subunit of a protein caused by protein binding is transmitted to all the other subunits, facilitating binding of additional substrate molecules to those subunits

feedback inhibition

a method of metabolic control in which the end product of a metabolic pathway acts as an inhibitor of an enzyme within that pathway

mesophyll

the tissue of the interior of the leaf where chloroplasts are usually found

stomata

a microscopic pore surrounded by guarded cells in the epidermis of eaves and stems that allows gas exchange between the environment and the interior of the plant (CO2 enters O2 exits

stroma

the dense fluid within the chloroplast surrounding the thylakoid membrane and containing ribosomes and DNA; Involved in the synthesis of organic molecules from CO2 and H2O (chloroplasts have an envelope of 2 membranes surrounding the stroma)

thylakoids

a flattened membraneous sac inside a chloroplast. Often exist in stacks called grand that are interconnected; their membranes contain molecular “machinery” used to convert light energy to chemical energy

chlorophyll

A green pigment located in membranes within the chloroplast of plants and algae and in the membranes of certain prokarys chlorophyll a participates directly in light runs which convert solar energy to chemical energy

Light rxns

the 1st of 2 major stages in photosynthesis. these runs which occur on the thylakoid membranes of the chloroplasts or on membranes of certain prokarys convert solar energy to the chemical energy of ATP and NADPH releasing oxygen in the process

Calvin cycle

2nd of 2 major stages in photosynthesis involving fixation of atmospheric carbon dioxide and reduction of the fixed carbon into carbs

NADPH

the reduced form of NADP+which temporarily stores electrons produced during the light runs. NADPH acts as a “reducing” power that can be passed along to an electron acceptor reducing it

photophosphorylation

the process of generating ATP from ADP and prostate by means of chemiosmosis using a proton motive force generated across the thylakoid membrane of the chloroplast or the membrane of certain prokarys during the light rxn of photosynthesis

carbon fixation

the initial incorporation of carbon from CO2 into an organic compound by an autotrophic organism

wavelength

the distance between crests of waves such as those of the electromagnetic spectrum

visible light

the portion of the electromagnetic spectrum that can be detected by various colors by the human eye

photons

a quantum or discrete quantity of light energy that behaves as if it were a particle

absorption

the range of a pigments ability to absorb various wavelengths of light; a graph of such a range

Chlorophyll a

a photosynthetic pigment that participate directly in the light runs, which convert solar energy to chemical energy

chlorophyll b

an accessory photosynthetic pigment that transfers energy to chlorophyll a

action spectrum

a graph that profiles the relative effectiveness of different wavelengths of radiation in driving a particular process

cartenoids

accessory pigments, either yellow or orange in chloroplasts of plants and in some prokarys by absorbing wavelengths of light that chlorophyll can’t they broaden the spectru, of colors that can drive photosynthesis