AP Bio Unit 3 Vocab

Metabolism

The combination of chemical reactions through which an organism builds up or breaks down materials

Enzymes

Protein substances that speed up chemical reactions

Catabolic Pathway

A metabolic pathway that releases energy by breaking down complex molecules to simpler compounds

Anabolic Pathway

A metabolic pathway that requires energy to build a complex molecule from simpler compounds

Energy

The ability to do work

Kinetic Energy

The energy of motion

Thermal energy

Heat energy

Potential Energy

The stored energy that matter possesses as a result of its position or internal structure

Chemical Energy

Potential energy available for release in a chemical reaction

First Law of Thermodynamics

Energy is neither created nor destroyed, but may be converted from one form to another

Second Law of Thermodynamics

When energy is changed from one form to another, some useful energy is always degraded into lower quality energy (usually heat)

Free Energy

Energy available to do work

Exergonic

Reactions that release energy (spontaneous reaction; neg. delta G)

Endergonic

Type of reaction that absorbs free energy from surroundings; because energy is stored in molecules, Gibbs free energy is positive; the reaction is non-spontaneous

ATP

(Adenosine Triphosphate) Main energy source that cells use for most of their work

Energy Coupling

The use of an exergonic process to drive an endergonic one

Phosphorylated Intermediate

A molecule (often a reactant) with a phosphate group covalently bound to it, making it more reactive (less stable) than the unphosphorylated molecule.

Activation Energy

Energy needed to get a reaction started

Active Site

The specific portion of an enzyme that attaches to the substrate by means of weak chemical bonds

Substrate

A specific reactant acted upon by an enzyme

Induced fit

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

Competitive Inhibitor

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

Noncompetitive Inhibitor

A substance that reduces the activity of an enzyme by binding to a location remote from the active site, changing its conformation so that it no longer binds to the substrate

Allosteric regulation

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

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

Fermentation

A catabolic process that makes a limited amount of ATP from glucose without an electron transport chain or oxygen and that produces ethyl alcohol or lactic acid.

Cellular Respiration

Process that releases energy by breaking down glucose and other food molecules in the presence or absence of oxygen

Aerobic Respiration

Respiration in which oxygen is consumed and glucose is broken down entirely; water, carbon dioxide, and large amounts of ATP are the final products.

Redox Reaction

A chemical reaction involving the transfer of one or more electrons from one reactant to another; also called oxidation-reduction reaction

Oxidation

A chemical reaction that involves the loss of an electron. Oxidation often involves the addition of oxygen and the loss of hydrogen ions

Reduction

The gain of electrons by a substance involved in a redox reaction (the charge of the substance becomes more negative)

NAD+

Nicotinamide adenine dinucleotide, a coenzyme present in all cells that helps enzymes transfer electrons during the redox reactions of metabolism

Electron Transport Chain

Series of proteins embedded in a membrane along which high-energy electrons are transported; as electrons are passed from molecule to molecule, energy is released

Glycolysis

Anaerobic process in which glucose is broken down into two molecules of pyruvate and two net ATP (makes a total of 4 ATP) and 2 NADH are produced

Citric Acid Cycle

A.K.A the Krebs Cycle. A chemical cycle involving eight steps that completes the metabolic breakdown of glucose molecules begun in glycolysis by oxidizing acetyl CoA (derived from pyruvate) to carbon dioxide; occurs within the mitochondrion. For each turn of this cycle, 2 CO2 released, 1ATP formed (substrate level phosphorylation via GTP intermediate, 3 NADH and 1 FADH2 is produced; NADH and FADH2 transports e-'s to electron transport chain.

Oxidative Phosphorylation

The total process of ATP production including the electron transport chain and chemiosmosis

ATP Synthase

Protein structure in cell mitochondria that uses energy from H+ ions to convert ADP to ATP by adding a phosphate group

Chemiosmosis

A process for synthesizing ATP using the energy of an electrochemical gradient and the ATP synthase enzyme.

Alcohol Fermentation

Anaerobic ATP-forming pathway. Pyruvate from glycolysis is degraded to acetaldehyde, which accepts electrons from NADH (acetaldehyde is reduced/becomes more electronegative) to form ethanol; NAD+ needed for the reactions is regenerated.

Lactic Acid Fermentation

Pyruvate from glycolysis is directly reduced by NADH to form lactate/lactic acid and NAD+ as an end product

Autotrophic

Self-feeder; pertaining to the ability of an organism to produce its own nutrients from inorganic sources obtained from the environment

Chloroplasts

Organelles that capture the energy from sunlight and convert it into chemical energy in a process called photosynthesis

Thylakoids

Flattened membrane sacs inside the chloroplast (inner membrane), used to convert light energy to chemical energy.

Photosynthesis

Process by which plants and some other organisms use light energy to convert water and carbon dioxide into oxygen, sugars and starches

Light Reactions

Phase of photosynthesis where energy form light dependent reactions is used to produced glucose and additional ATP molecules; Solar energy is converted to chemical energy

Calvin Cycle

Second stage of photosynthesis in which energy from ATP and NADPH is used to make sugars

NADH

A reduced form of NAD+. An energy-carrying coenzyme produced by glycolysis and the Krebs cycle. NADH carries energy to the electron transport chain, where it is stored in ATP.

NADPH

A reduced form of NADP+; a source of electrons as "reducing power" that can be passed along to an electron receptor, thereby reducing it. It provides electrons for photosynthesis

Stroma

Fuid of the chloroplast surrounding the thylakoid membrane; involved in the synthesis of organic molecules from carbon dioxide and water

Visible Light

The portion of the electromagnetic spectrum that can be detected as various colors by the human eye, ranging in wavelength from about 380 nm to about 750 nm

Wavelengths

The distance between the crests of electromagnetic waves

Photon

A discrete quantity (quantum) of light energy that behaves like it is a particle

Primary Electron Acceptor

In a reaction center complex, the molecule capable of accepting electrons and becoming reduced