Chapter 4: Cells and Energy

ATP and Energy

Animated article explaining the pathway of energy transfer from food to ATP to energy the cell can use to drive processes such as molecular synthesis.

(Main Ideas: The chemical energy used for most cell processes is carried by ATP. Organisms break down carbon-based molecules to produce ATP.)


Interactive illustration comparing photosynthesis with chemosynthesis.

(Main Idea: A few types of organisms do not need sunlight and photosynthesis as a source of energy.)

Earth’s Producers

Video about phytoplankton, which are perhaps Earth’s most important photosynthesizing organisms

(Main Idea: Photosynthetic organisms are producers.)


Animation describing the light-dependent reactions of photosynthesis in depth

(Main Idea: The first stage of photosynthesis captures and transfers energy.)

Cellular Respiration

Simple animation to give you a feel for how glycolysis, the Krebs cycle, and the electron transport chain are all related

(Main Idea: Cellular respiration makes ATP by breaking down sugars.)

Electron Transport Chain

Animation describing the electron transport chain in depth

(Main Idea: The electron transport chain is the second major part of cellular respiration.)

Glycolysis and Fermentation

Interactive tutorial in which you carry out glycolysis and fermentation by moving the appropriate enzymes and molecules around a carbon-based molecule

(Main Idea: Fermentation allows glycolysis to continue.)