AP Biology Unit 3 – Cellular Energetics: Ultimate Study Notes

What is the main energy currency of the cell?

ATP (Adenosine Triphosphate)

What happens when ATP is hydrolyzed?

ATP → ADP + Pi + energy

What types of cellular processes are powered by ATP?

Active transport, macromolecule synthesis, movement, nerve impulses

How do cells regenerate ATP from ADP?

Through phosphate addition (phosphorylation)

ATP can be thought of as:

A rechargeable battery

What is an enzyme?

A biological catalyst that speeds up reactions

How does an enzyme work?

It binds to a substrate at the active site, forms a complex, releases products

What factors can denature an enzyme?

Temperature, pH, high ion concentration

What is the difference between competitive and noncompetitive inhibitors?

Competitive binds at the active site; noncompetitive binds elsewhere

General equation for cellular respiration:

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP

Where does glycolysis occur?

Cytoplasm

Glycolysis net products per glucose?

2 ATP, 2 NADH, 2 pyruvate

Does glycolysis require oxygen?

No, it is anaerobic

Krebs (Citric Acid) Cycle occurs in:

Mitochondrial matrix

Main products of Krebs Cycle per glucose?

2 ATP, NADH, FADH₂, CO₂

Electron Transport Chain (ETC) occurs in:

Inner mitochondrial membrane

Final electron acceptor in ETC is:

Oxygen

ATP synthase uses:

Proton gradient (H⁺) across inner membrane

Anaerobic respiration (fermentation) regenerates:

NAD⁺

Example of lactic acid fermentation:

Human muscle cells during low O₂

“OIL RIG” in cellular respiration refers to:

Oxidation Is Loss, Reduction Is Gain (electrons)

Overall simplified equation:

6CO₂ + 12H₂O + light → C₆H₁₂O₆ + 6O₂ + 6H₂O

Light-dependent reactions occur in:

Thylakoid membranes

Products of light-dependent reactions:

ATP, NADPH, O₂

Calvin Cycle occurs in:

Stroma of chloroplast

Calvin Cycle requires:

ATP, NADPH, CO₂

C3 plants fix CO₂:

Directly in Calvin Cycle

C4 and CAM plants use modified pathways to:

Conserve water in hot/dry environments

Both photosynthesis and respiration use:

Proton gradients + ATP synthase to make ATP

Products of photosynthesis are:

Reactants for cellular respiration

Products of cellular respiration are:

Reactants for photosynthesis (CO₂ and H₂O)