Unit 4
Energy in living things.
Photosynthesis, which builds sugar from air, water and light, and respiration, which stores its energy in ATP.
Before this unit
The unit, lesson by lesson
Lessons
4 lessons · 23 practice questions · about 2 hours
Photosynthesis
How a plant builds sugar from carbon dioxide and water with light, where its mass and the oxygen it gives off come from, and what sets the rate.
Limiting factors
Light, carbon dioxide and temperature: the rate is set by whichever is scarce, and raising one factor helps only until another becomes limiting.
Cellular respiration
How a cell breaks glucose down with oxygen: glycolysis, the Krebs cycle and the electron transport chain, and how much ATP each stage gives.
Without oxygen
What happens when there is not enough oxygen: glycolysis alone, lactate in muscles, alcohol and carbon dioxide in yeast, and the ATP sums when the oxygen is partial.