Photosynthesis & Cellular Respiration vocab

Photosynthesis

the process by which plants use light energy to convert carbon dioxide and water into glucose and oxygen.

Chloroplast

the organelle in plant cells where photosynthesis occurs.

Chlorophyll

a green pigment that absorbs light energy

Light reactions

the first stage of photosynthesis that uses light energy to produce ATP

Calvin cycle

the second stage of photosynthesis that uses ATP and NADPH to build sugar (G3P).

Thylakoid

a membrane structure inside the chloroplast where the light reactions occur.

Stroma

the fluid-filled space surrounding the thylakoids where the Calvin cycle occurs.

Photosystem I & II

groups of proteins and pigments that absorb light energy and excite electrons.

Water splitting (photolysis)

the splitting of water molecules during the light reactions to produce oxygen

Oxygen (O₂)

a waste product of photosynthesis and a reactant in cellular respiration.

ATP

the main energy-carrying molecule used by cells.

NADPH

an electron carrier produced in the light reactions and used in the Calvin cycle.

ADP

a low-energy molecule that becomes ATP when a phosphate is added.

NADP⁺

an electron carrier that becomes NADPH after gaining electrons.

Glucose (photosynthesis)

a six-carbon sugar that stores chemical energy.

RuBisCO

an enzyme that attaches carbon dioxide to RuBP in the Calvin cycle.

Chemiosmosis

the process of making ATP using a proton gradient and ATP synthase.

Endergonic reaction

a reaction that requires energy input

Cellular respiration

the process by which cells break down glucose to release energy in the form of ATP.

Glucose (respiration)

the primary fuel molecule used in cellular respiration.

Glycolysis

the first stage of cellular respiration that breaks glucose into pyruvate in the cytoplasm.

Pyruvate

a three-carbon molecule produced during glycolysis.

Citric acid cycle (Krebs cycle)

the stage of respiration that releases CO₂ and transfers energy to electron carriers.

Electron transport chain (ETC)

a series of proteins that transfer electrons and create a proton gradient.

Oxidative phosphorylation

ATP production using the electron transport chain and chemiosmosis.

ATP synthase

an enzyme that produces ATP as protons flow through it.

Proton gradient

a difference in hydrogen ion concentration across a membrane.

NADH

an electron carrier that delivers electrons to the electron transport chain.

FADH₂

another electron carrier that delivers electrons to the electron transport chain.

Oxygen (final electron acceptor)

the molecule that accepts electrons at the end of the ETC

Carbon dioxide (CO₂)

a waste product released during the citric acid cycle.

Water (H₂O)

a product of cellular respiration formed when oxygen accepts electrons.

Aerobic respiration

respiration that requires oxygen.

Anaerobic respiration

respiration that occurs without oxygen.

Fermentation

an anaerobic pathway that allows glycolysis to continue without oxygen.

Mitochondrial matrix

the inner space of the mitochondrion where the citric acid cycle occurs.

Inner mitochondrial membrane

the location of the electron transport chain.

Exergonic reaction

a reaction that releases energy

ATP (energy currency)

the molecule cells use for immediate energy.

Electrons

high-energy particles transferred during chemical reactions.

Energy transfer

the movement of energy through chemical reactions.

Enzymes

proteins that speed up chemical reactions.