Metabolism, Cellular Respiration, and Photosynthesis Vocabulary

Comprehensive vocabulary flashcards covering chemical reactions, enzyme kinetics, cellular respiration stages, and photosynthetic processes.

Metabolism

All chemical reactions in a cell.

Catabolic reaction

Breaks molecules down and releases energy.

Anabolic reaction

Builds larger molecules and requires energy.

Kinetic energy

Energy of movement.

Potential energy

Stored energy.

Exergonic reaction

Releases free energy; $\Delta G$ is negative.

Endergonic reaction

Needs an energy input; $\Delta G$ is positive.

ATP

The cell’s main immediate energy source.

ATP hydrolysis

Breaks ATP into ADP and phosphate, releasing usable energy.

Enzyme

A catalyst that speeds up a reaction.

Activation energy

Energy needed to start a reaction.

Active site

Part of an enzyme where the substrate binds.

Substrate

Molecule an enzyme acts on.

Denaturation

When a protein loses its shape and may stop working.

Competitive inhibitor

Blocks an enzyme by competing for its active site.

Noncompetitive inhibitor

Binds away fom the active site and reduces enzyme activity.

Feedback inhibition

A pahway’s final product slows an earlier step.

Cellular respiration

Breaks down food molecules to make ATP.

Glycolysis

Splits glucose into two pyruvate; makes $2$ net ATP.

Cytosol

Fluid part of the cell where glycolysis happens.

Pyruvate

Three-carbon molecule made by glycolysis.

Acetyl-CoA

Two-carbon molecule that enters the Krebs cycle.

Pyruvate oxidation

Turns pyruvate into acetyl-CoA, making NADH and $CO_2$.

Krebs cycle

Releases $CO_2$ and makes NADH, $FADH_2$, and some ATP.

NADH

Carries high-energy electrons to the electron transport chain.

$$FADH_2$$

Another electron carrier used in respiration.

Electron transport chain (ETC)

Ues electrons to pump $H^+$ and build a gradient.

Chemiosmosis

$H^+$ flows through ATP synthase to help make ATP.

ATP synthase

Enzyme that makes ATP using a proton gradient.

Oxidative phosphorylation

Makes most ATP in aerobic respiration using the ETC and ATP synthase.

Oxygen

Final electron acceptor in aerobic respiration.

Fermentation

Regenerates $NAD^+$ so glycolysis can continue without oxygen.

Lactic acid fermentation

Changes pyruvate to lactate and regenerates $NAD^+$.

Alcoholic fermentation

Makes ethanol and $CO_2$ and regenerates $NAD^+$.

ATP yield of respiration

Usually about $30-32$ ATP per glucose in eukaryotes.

Photosynthesis

Uses light energy to build sugars from $CO_2$.

Chloroplast

Organelle where photosynthesis happens.

Thylakoid

Membrane sac where light reactions occur.

Stroma

Fluid in chloroplast where the Calvin cycle occurs.

Light reactions

Use light and water to make ATP, NADPH, and $O_2$.

Photosystem II (PSII)

Uses light and splits water, releasing oxygen.

Photosystem I (PSI)

Uses light to energize electrons for NADPH production.

NADPH

Carries electrons to the Calvin cycle.

Calvin cycle

Uses $CO_2$, ATP, and NADPH to make G3P.

Carbon fixation

Adding $CO_2$ carbon to an organic molecule.

Rubisco

Enzyme that attaches $CO_2$ to RuBP.

RuBP

Five-carbon molecule that accepts $CO_2$ in the Calvin cycle.

G3P

Three-carbon sugar made by the Calvin cycle.

Cyclic electron flow

Uses PSI to make extra ATP but not NADPH or $O_2$.

Photorespiration

Rubisco uses $O_2$ instead of $CO_2$, wasting energy.

C3 plants

Plants that first fix $CO_2$ into a three-carbon compound.

C4 plants

Separate $CO_2$ capture and Calvin cycle into different cells.

CAM plants

Open stomata at night to save water.