AP Bio Unit 3 (Cellular Energetics)

Enzymes

Proteins that catalyze (speed up) reactions by lowering the activation energy (Initial energy to start a reaction)

Substrate

The specific substance on which an enzyme acts during a chemical reaction

Enzyme-substate complex

The temporary molecule created when the substrate binds to the enzyme’s active site

Active Site

The area on an enzyme where the substrate binds to

Catalyst

A substance that speeds up a chemical reactions without being used up or permanently changed (ie - enzymes)

pH

The measure of how acidic (0-6) or basic (8-14) a solution is

Denaturization

A loss in both structure and function of an enzyme due to conditions that cause it to unfold from its normal conformation

Adenosine Triphosphate (ATP)

A molecule that organisms use as a source of energy to perform work

Kinetic energy

The energy associated with motion

Potential energy

Stored energy

Energy

The ability to do work, which is any change in the state of motion or matter

Endergonic reactions

Chemical reactions that need energy

Exergonic reactions

Chemical reactions that release energy

Catabolic pathways

Pathways that break down complex molecules. They release energy

Anabolic Pathways

Pathways that build complex molecules from simpler compounds. They require energy

Activation energy

The initial input of energy to start a reaction

Law of Thermodynamics

1) energy cannot be created or destroyed, but it can be transferred or transformed

2) energy transformation increases the entropy of the universe, and when energy is converted from one form to another, some energy is lost as heat

C₄ plants

Plants with adaptations to survive in hot, dry climates. Mesophyll fixes CO₂ into 4-C compound to reduce the chance of RubisCO reacting with O₂

Light-capturing complex

Parts of photosystems that absorb light and transfer energy to the reaction center. The complex is a group of pigments (chlorophyll a, chlorophyll b, cartenoids) embedded in a protein matrix

NADPH

An electron carrier molecule in photosynthesis, which carries electrons from the light-dependent reaction to the Calvin cycle

Light

A form of electromagnetic energy

Stomata

Microscopic pores on leaves where O₂ exits and CO₂ enters

Stroma

Dense interior fluid in chloroplasts

Thylakoids

Flattened sacs containing chlorophyll pigments

Reaction Center

Where light energy is converted to chemical energy

Chlorophyll

The green pigment that absorbs photons to power photosynthesis

Redox reactions

A series of reactions involving the complete or partial transfer of one or more electrons from one reactant to another

Oxidation

The loss of electrons

Pigments

Contain electrons that absorb light energy for photosynthesis

Photosynthesis

The conversion of light energy to chemical energy

Photons

Particles of energy

Wavelength

The distance from one crest of one wave to the crest of the next

Reduction

The gain of electrons (REDUCES the positive charge)

Photoproection

The process of how plants get rid of extra light energy safely to avoid damage

Heterotrophs

Organisms that cannot make their own food, and therefore live off of other organisms

Calvin Cycle

Second stage of photosynthesis where ATP and NADPH are used to make glucose from CO₂

Chloroplast

The primary location of photosynthesis

Grana

Stacks of thylakoids

Photosystems

The reaction centers and light-capturing complexes of photosynthesis

Mesophyll

Inner tissue of leaves, containing many chloroplasts

Photorespiration

When RubisCO accidentally used O₂ instead of CO₂ during photosynthesis, wasting energy

G3P (PGAL)

A sugar made in the Calvin Cycle

CAM Plant

A type of plant that has adapted to very hot and dry climates by changing when it takes in CO₂

Cellular Respiration

A process that releases energy by breaking down glucose and other food molecules in the presence of oxygen

NAD+

The electron carrier involved in glycolysis

FADH

Energy carrier that transports less energy than NADH but more than ATP

Glycolysis

The stage in cellular respiration that breaks glucose into 2 pyruvate molecules

Pyruvate Oxidation

2nd step in cellular respiration when pyruvate enters the mitochondrion

Citric Acid Cycle (Krebs Cycle)

Completes breakdown of glucose

Chemiosmosis

Process for synthesizing ATP using the energy from the ETC and ATP Synthase

APT Synthase

Enzyme that binds ADP and Pi to create ATP

Anaerobic Respiration

Respiration that does not require oxygen

Fermentation

The process by which cells release energy in the absence of oxygen