AP Biology Unit 3 Study Guide - Photosynthesis & Cellular Respiration

This set of flashcards covers key concepts from the AP Biology Unit 3 lecture on Photosynthesis and Cellular Respiration, focusing on essential terms, processes, and their interactions.

What are the two core processes that manage energy in living systems?

Photosynthesis and Cellular Respiration.

What is the main difference in how photosynthesis and cellular respiration handle energy?

Photosynthesis stores energy from sunlight in chemical bonds, while cellular respiration releases energy from sugars to make ATP.

What does photosynthesis primarily convert?

Light energy into chemical energy.

What two major products does photosynthesis provide to ecosystems?

Organic molecules (food) and oxygen.

Where do the light reactions of photosynthesis occur?

In the thylakoid membrane.

What happens to electrons in the light reactions?

Chlorophyll absorbs light, energizing electrons that move through the electron transport chain.

What is necessary for a proton gradient to form during photosynthesis?

A membrane is required to separate charges.

What is the purpose of the Calvin Cycle?

To build organic molecules using CO₂, ATP, and NADPH.

Why does the Calvin Cycle slow if CO₂ levels drop?

Because CO₂ is necessary for carbon fixation.

What does 'local order but global disorder' refer to in photosynthesis?

Cells become more ordered, but the surroundings become more disordered.

What is the purpose of cellular respiration?

To convert chemical energy in food into ATP.

What are the stages of cellular respiration?

Glycolysis, Pyruvate Oxidation, Krebs Cycle, and Electron Transport Chain.

What is the role of oxygen in cellular respiration?

Oxygen is the final electron acceptor.

What is fermentation and its purpose?

A process that regenerates NAD to allow glycolysis to continue, occurring without oxygen.

Why doesn’t fermentation produce much ATP?

Because glucose is not fully oxidized and the electron transport chain is not utilized.

What happens if the proton gradient collapses?

ATP synthesis stops.

How are photosynthesis and respiration considered mirror processes?

Photosynthesis stores energy using electron flow and gradients, while respiration releases energy using the same mechanisms.