AP BIO

What do enzymes do?

Enzymes are biological catalysts that speed up chemical reactions by lowering activation energy without being consumed.

What is activation energy?

The minimum energy required to start a chemical reaction.

How do environmental conditions affect enzyme activity?

Temperature: too high denatures, too low slows; pH: optimal range; substrate concentration: increases rate until saturation.

What is enzyme denaturation?

A change in enzyme shape that makes it unable to function.

What are inhibitors?

Molecules that reduce enzyme activity; competitive inhibitors compete for the active site, noncompetitive bind elsewhere and change shape.

What is ATP?

Adenosine triphosphate, the main energy carrier in cells.

What is the structure of ATP?

Adenine, ribose sugar, and three phosphate groups.

How does ATP store energy?

In the bonds between phosphate groups, especially the last phosphate.

What happens when ATP is hydrolyzed?

ATP becomes ADP + Pi and releases energy.

What is an exergonic reaction?

A reaction that releases energy.

What is an endergonic reaction?

A reaction that requires energy input.

How are ATP and endergonic reactions connected?

ATP hydrolysis provides energy to drive endergonic reactions.

What is photosynthesis?

The process by which plants convert light energy into chemical energy stored in glucose.

Where does photosynthesis occur?

In the chloroplast; light reactions in thylakoid membrane, Calvin cycle in stroma.

What is the overall equation for photosynthesis?

6CO2 + 6H2O + light → C6H12O6 + 6O2.

What happens in the light-dependent reactions?

Use light to split water and produce ATP, NADPH, and O2.

What is photolysis?

The splitting of water using light to produce oxygen, electrons, and H+ ions.

What happens in the Calvin cycle?

Uses CO2, ATP, and NADPH to produce G3P.

What enzyme is key in the Calvin cycle?

RuBisCO, which fixes CO2.

What is carbon fixation?

The incorporation of CO2 into an organic molecule.

What is G3P?

A 3-carbon sugar produced in the Calvin cycle.

What is cellular respiration?

The process of breaking down glucose to produce ATP.

What is the overall equation for cellular respiration?

C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP.

What are the 3 main stages of cellular respiration?

Glycolysis, Krebs cycle, Electron Transport Chain.

Where does glycolysis occur?

In the cytoplasm.

What are the products of glycolysis?

2 pyruvate, 2 ATP (net), 2 NADH.

Where does the Krebs cycle occur?

In the mitochondrial matrix.

What are the main products of the Krebs cycle?

CO2, NADH, FADH2, and a small amount of ATP.

Where does the Electron Transport Chain occur?

In the inner mitochondrial membrane.

What happens in the Electron Transport Chain?

Electrons create a proton gradient used to make ATP.

What is oxidative phosphorylation?

ATP production using the ETC and chemiosmosis.

What is the role of oxygen in cellular respiration?

Final electron acceptor that forms water.

What is fermentation?

An anaerobic process that regenerates NAD+ so glycolysis can continue.

What are the types of fermentation?

Lactic acid fermentation and alcohol fermentation.

How are photosynthesis and cellular respiration related?

Products of one are reactants of the other; photosynthesis stores energy, respiration releases it.