Cellular energetics vocab

Strictly definitions; see the concepts deck for words in context

Activation energy

Energy input necessary for all chemical reactions to occur

Energy barrier

Amount of activation energy that reactants must absorb to become activated and start a chemical reaction

Catalyst

Substance that speeds up the rate of a chemical reaction

Substrate

Specific reactant that an enzyme binds with

Active site

Region of the enzyme that the substrate binds to

Induced fit

When the active site changes shape slightly to fit the substrate more snugly

Substrate-enzyme complex

When the enzyme bonds to the substrate

Denaturation

Change in shape of a protein

Competitive inhibitors

Resembles the normal substrate and fights with it for the active site

Non-competitive inhibitors

Bind outside of the active site, changing the shape of the enzyme

Allosteric site

Where the non-competitive inhibitor binds to the enzyme

Feedback inhibition

When too much product is created and it becomes an inhibitor

Endergonic reaction

Energy is absorbed

Exergonic reaction

Energy is released

Cellular metabolism

Sum of endergonic and exergonic reactions in a cell

Energy coupling

Using the energy released from exergonic reactions to fuel endergonic reactions

Phosphorylation

Transfer of a phosphate group onto another molecule

First Law of Thermodynamics

Energy is neither created nor destroyed

Second Law of Thermodynamics

Every reaction in a closed system increases its entropy

Entropy

Measure of disorder

Oxidation

Loss of electrons in a transfer from one molecule to another

Reduction

Gain of electrons in a transfer from one molecule to another

Aerobic

Requires oxygen

Anaerobic

Does not require oxygen

ATP synthase

Protein channel that turns ADP into ATP

Chemiosmosis

Flow of hydrogen ions down the concentration gradient, through ATP synthase

Autotroph

Organism that can make food and sustain itself without eating other organisms

Photoautotroph

Autotroph that produces food using light energy

Cyanobacteria

Autotrophic bacteria

Mesophyll

Green tissue inside a leaf

Stomata

Pores in leafs through which carbon dioxide leaves enters and oxygen enters

Veins

Deliver water absorbed by the roots to the leaves

Stroma

Thick fluid inside the inner membrane of a chloroplast

Thylakoid

Disc-shaped sacs that contain chlorophyll

Grana

Stacks of thylakoids

Matrix

Fluid inside the inner membrane of mitochondria

Pigment

Structure that absorbs some wavelengths of light and reflects others, creating color

Chlorophyll

Main pigment in chloroplasts

Calvin cycle

Another name for light-independent reactions

Anabolic reaction

Two reactants become one product

Catabolic reaction

One reactant becomes two or more products

Lock and key model

Models how specific an enzyme is to a substrate, like how a lock is specific to a key

Strict anaerobe

Organism that requires anaerobic conditions and is poisoned by oxygen

Facultative anaerobe

Organism that does aerobic respiration when oxygen is present but can also do fermentation

Citric acid cycle

Another name for the Krebs cycle

Endosymbiotic theory

Chloroplasts evolved from autotrophic prokaryotic cells that engulfed each other