Chapter 9 Energy in a Cell

Adenosine Triphosphate Main molecule of energy in all living things Energy is stored in the bonds that attach the phosphate groups Energy is released when those bonds are broken

Why do we need energy? To perform all of our life functions Ex] moving, digesting food, breathing, moving substances through the organism

Photosynthesis

Process of converting sunlight into stored energy Occurs in the chloroplast 6CO2 + 6H2O  C6H12O6 + 6O2

Chloroplast

Light-Dependent Reactions Occurs in the thylakoid membrane of the chloroplast Sunlight energizes electrons Enter into a chain to transfer the energy When they reach the end of the chain, remaining energy is transferred to a molecule called NADPH and moved to the next cycle.

Light-Independent Reactions Also called the Calvin cycle Occurs in the stroma of the chloroplast Uses carbon dioxide to make sugar

Who performs photosynthesis? Plants Some protists Some bacteria

Cellular Respiration Process of changing food into energy

Glycolysis Occurs in the cytoplasm Produces 4 ATP molecules 2 ATP molecules are needed to start glycolysis Net gain after glycolysis: 2 ATP

Anaerobic vs. Aerobic Respiration If oxygen is available – aerobic respiration If oxygen is not available – anaerobic respiration Cells prefer aerobic respiration – WHY?

Aerobic Respiration Occurs in the mitochondria Krebs cycle produces 2 ATP Electron transport chain produces 32 ATP From one molecule of glucose, 38 ATP are produced Net gain = 36 ATP C6H12O6 + 6O2  6CO2 + 6H2O

Anaerobic Respiration Produces 2 ATP Net gain of 4 ATP Lactic acid and alcoholic fermentation

Lactic Acid Fermentation Occurs in human muscle cells Produces burning sensation

Alcoholic Fermentation Produces carbon dioxide Important in bread and alcohol production

Who performs cellular respiration? EVERYONE!!!