AP bio unt 3

1st Law of Thermodynamics

states that the total amount of energy in the universe is constant; energy cannot be created or destroyed, but it can be transformed and transferred. 

2nd Law of Thermodynamics

all energy transfers involve the loss of some amount of energy in an unusable form such as heat, resulting in entropy; entropy of a system is always increasing

Absorption Spectrum

range of wavelengths of electromagnetic radiation absorbed by a given substance

Acetyl CoA

combination of an acetyl group derived from pyruvic acid and coenzyme A, which is made from pantothenic acid (a B-group vitamin)

Action Spectrum

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

Activation Energy

energy necessary for reactions to occur

Active Site

specific region of the enzyme to which the substrate binds

ADP

a lower-energy molecule that can be converted into ATP by the addition of a phosphate group

Aerobic Respiration

process in which organisms convert energy in the presence of oxygen

Alcoholic Fermentation

1. glycolysis followed by the reduction of pyruvate to ethyl alcohol, regenerating NAD+ and releasing carbon dioxide

Allosteric Inhibition

inhibition by a binding event at a site different from the active site, which induces a conformational change and reduces the affinity of the enzyme for its substrate

Allosteric Site

an alternate part of the enzyme that can bind to non–substrate molecules.

Anabolic

pathways that require an input of energy to synthesize complex molecules from simpler ones

Anaerobic respiration

process in which organisms convert energy for their use in the absence of oxygen

ATP

adenosine triphosphate, the cell’s energy currency

ATP Synthase

membrane-embedded protein complex that adds a phosphate to ADP with energy from protons diffusing through it

Autotroph

organism that produces organic molecules from small inorganic compounds

Calvin Cycle

light-independent reactions of photosynthesis that convert carbon dioxide from the atmosphere into carbohydrates using the energy and reducing power of ATP and NADPH

Carbon Dioxide

a gas that is expelled from the body by the respiratory system.

Catabolic

pathways in which complex molecules are broken down into simpler ones

Catalyst

a substance that speeds up a chemical reaction without being consumed in the process

Catalyze

 to significantly speed up a chemical reaction by using a catalyst

Cellular Respiration

the metabolic process by which cells convert chemical energy from glucose (food) into usable energy (ATP) through a series of controlled reactions, primarily utilizing oxygen to generate carbon dioxide and water as byproducts

Chemiosmosis

process in which there is a production of adenosine triphosphate (ATP) in cellular metabolism by the involvement of a proton gradient across a membrane

Chlorophyll

green pigment that captures the light energy that drives the light reactions of photosynthesis

Chloroplast

organelle in which photosynthesis takes place

Coenzyme

small organic molecule, such as a vitamin or its derivative, which is required to enhance the activity of an enzyme

Competitive Inhibition

type of inhibition in which the inhibitor competes with the substrate molecule by binding to the active site of the enzyme

Electrochemical Gradient

the diffusion gradient of an ion, representing a type of potential energy that accounts for both the concentration difference of the ion across a membrane and its tendency to move relative to the membrane potential

Electron

 a subatomic particle with a single negative electrical charge and a (negligible) mass about 1/2000 that of a neutron or a proton. One or more electrons move around the nucleus of an atom

Electron Acceptor

a compound that can accept a pair of high-energy electrons and transfer them, along with most of their energy, to another molecule

Electron Carrier Molecule

A sequence of electron carrier molecules (membrane proteins) that shuttle electrons during the redox reactions that release energy used to make ATP.

Electron Transport Chain

group of proteins between PSII and PSI that pass energized electrons and use the energy released by the electrons to move hydrogen ions against their concentration gradient into the thylakoid lumen

Endergonic Reaction

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

Endothermic

(of a chemical reaction or compound) occurring or formed with absorption of heat

Energy Coupling

process during which energy released by one reaction is used to drive another reaction

Energy decoupling

Exergonic and Endergonic reactions happening separately of each other

Enzyme

catalyst in a biochemical reaction that is usually a complex or conjugated protein

Exergonic Reaction

a spontaneous chemical reaction in which there is a net release of energy

FADH2

electron carrier produced during the Krebs cycle

Fermentation

process of regenerating NAD+ with either an inorganic or organic compound serving as the final electron acceptor; occurs in the absence of oxygen

Glucose

the form of sugar that circulates in the blood and provides the major source of energy for body tissues. When its level is low, we feel hunger.

Glycolysis

process of breaking glucose into two three-carbon molecules with the production of ATP and NADH

Granum

stack of thylakoids located inside a chloroplast

Heterotroph

 organism that consumes organic substances or other organisms for food

Induced fit

dynamic fit between the enzyme and its substrate, in which both components modify their structures to allow for ideal binding

Inner membrane

The membrane of the mitochondria that is the site of electron transport and chemiosmosis

Inorganic Phosphate

Derived from phosphoric acid, the molecule that forms high-energy bonds for energy storage in nucleotide triphosphates like ATP; also used for enzyme regulation.

Intermembrane Space

the fluid filled space between the inner and outer mitochondrial membranes

Krebs Cycle

series of enzyme-catalyzed chemical reactions of central importance in all living cells

Lactic Acid Fermentation

Glycolysis followed by the reduction of pyruvate to lactate, regenerating NAD+ with no release of carbon dioxide

Light Reactions

the first of two major stages in photosynthesis (preceding the Calvin Cycle). These reactions, which occur on the thylakoid membranes of the chloroplast or on the membranes of certain prokaryotes, convert light energy to chemical energy of ATP and NADPH, releasing oxygen in the process

Metabolism

all the chemical reactions that take place inside cells, including anabolism and catabolism

NAD+

nicotinamide adenine dinucleotide, a coenzyme that cycles easily between oxidized NAD+ and NADH states, thus acting as an electron carrier

NADH

 the reduced form of NAD+; an electron-carrying molecule that functions in cellular respiration

NADP+

nicotinamide adenine dinucleotide phosphate, an electron acceptor that, as NADPH, temporarily stores energized electrons produces during the light reactions

NADPH

 an electron carrier that provides high-energy electrons for photosynthesis

Negative Feedback

feedback to a control mechanism that increases or decreases a stimulus instead of maintaining it

Optimal Range

the range of environmental factors to which an organism is best adapted

Outer Membrane

 the outermost membrane in the mitochondria that protects and holds the form of the organelle.

Oxidative Phosphorylation

production of ATP using the process of chemiosmosis and oxygen

Oxygen

gas that enters the blood through the lungs and travels to the heart to be pumped via arteries to all body cells

Phosphorylation

addition of a high-energy phosphate to a compound, usually a metabolic intermediate, a protein, or ADP

Photosynthesis

series of reactions that use carbon dioxide, water, and light energy to make glucose and oxygen

Photosystem I and II

Light harvesting complexes with its associated electron transport chain. Located in thylakoid membranes and take place during the Light Dependent Reactions.

Product

molecule(s) found on the right side of a chemical equation

Proton (H+)

positively charged particle that resides in the nucleus of an atom; has a mass of one amu and a charge of +1

Pyruvate

three-carbon sugar that can be decarboxylated and oxidized to make acetyl CoA, which enters the citric acid cycle under aerobic conditions; the end product of glycolysis

Reactant

molecule(s) found on the left side of a chemical equation

Ribulose Biphosphate

A five-carbon compound that combines with CO2 in the first step of the Calvin cycle during photosynthesis.

Ribulose Biphosphate Carboxylase

key enzyme involved in the first step of carbon fixation in photosynthesis

Stomata

opening that regulates gas exchange and water evaporation between leaves and the environment, typically situated on the underside of leaves (stoma = singular)

Stroma

fluid-filled space surrounding the grana inside a chloroplast where the light-independent reactions of photosynthesis take place

Substrate Level Phosphorylation

production of ATP from ADP using the excess energy from a chemical reaction and a phosphate group from a reactant

Thylakoid Membrane

The photosynthetic membrane within a chloroplast that contains light gathering pigment molecules and electron transport chains.

Wavelength

distance between consecutive points of equal position (two crests or two troughs) of a wave in a graphic representation; inversely proportional to the energy of the radiation