KEY CONCEPT All cells need chemical energy.

Photosynthesis & Cellular Respiration The “Big Picture” Light is sent to leaves of plants

(In Autotrophs only) Process of Photosynthesis Chlorophyll in a plant’s chloroplast absorbs the light energy and converts it into glucose, a carbohydrate. (In ALL cells) Process of Cellular Respiration Mitochondria break down the glucose to form ATP which is a stored and useable form of energy

Photosynthesis Cellular Respiration (In all cells) ATP Cycle The chemical energy used for most cell processes is supplied by ATP molecules.

ATP Molecules Phosphate groups Adenosine (adenine + ribose) tri=3 di=2

ATP Cycle The ATP cycle is like a rechargeable battery. Breaking off a ~P uses energy. Adding a ~P adds energy. A P ~ P ~P High energy bonds A P ~ P ~P (ATP) A P ~ P (ADP) A P (AMP)

Energy is released when a phosphate is removed ATP Cycle (continued) Energy is released when a phosphate is removed Energy is added when a phosphate is added phosphate removed

Organisms break down organic molecules to make ATP. Carbohydrates are the molecules most commonly broken down to make ATP. up to 36 ATP from one glucose molecule Lipids store the most energy. 80 percent of the energy in your body about 146 ATP from a fat Proteins are least likely to be broken down to make ATP. amino acids not usually needed for energy about the same amount of energy as a carbohydrate

Comparison of Energy from Organic Compounds