Photosynthesis & Cellular Respiration

How is light energy converted into chemical energy during photosynthesis?

Light energy is absorbed by chlorophyll, exciting electrons that are used to produce ATP and NADPH

Role of water in the light reactions

Water is split to provide electrons and hydrogen ions; oxygen is released as a waste product.

Inputs and outputs of the light reactions

Inputs: light, water
Outputs: ATP, NADPH, oxygen

Inputs and outputs of the Calvin cycle

Inputs: ATP, NADPH, CO₂
Outputs: G3P (sugar)

Why does the Calvin cycle depend on the light reactions?

It requires ATP and NADPH produced during the light reactions.

Effect of chlorophyll’s light absorption on photosynthesis rate

Photosynthesis is fastest at wavelengths chlorophyll absorbs best.

Path of glucose through cellular respiration

Glycolysis → citric acid cycle → electron transport chain

Why oxygen is essential for aerobic respiration

Oxygen accepts electrons at the end of the electron transport chain.

How ATP synthase produces ATP

Protons flow through ATP synthase, releasing energy to form ATP from ADP and phosphate.

Why blocking the electron transport chain is deadly

ATP cannot be produced efficiently, causing an energy shortage.

Aerobic respiration vs. fermentation

Aerobic respiration uses oxygen and produces much more ATP; fermentation occurs without oxygen and produces little ATP.

How photosynthesis and cellular respiration are interdependent

Photosynthesis provides glucose and oxygen; respiration provides CO₂ and water.

Energy flow in photosynthesis and respiration

Sunlight → glucose → ATP

Why electron transfer is central to both processes

Electron transfers release energy used to make ATP.