Cellular Respiration

Breaking down food to get energy

2 Basic Kinds of Respiration:

Aerobic Uses O2 to break down food Produces 38 ATP

Anaerobic Takes place without oxygen Produces 2 ATP

Glycolysis Both types of respiration begin with

glycolysis in the cytoplasm of the cell

Glucose, a molecule with 6 carbons, is split into 2 molecules each with 3 carbons called pyruvate

Energy is released: 2 ATP 2 NADH

If oxygen is present in cell…

The next step of aerobic respiration occurs The Krebs Cycle

Pyruvate enters the mitochondria In a series of steps pyruvate is

broken down into: 6 CO2 molecules are released 2 ATP are made Electron carriers are made

3 NADH 1 FADH2

The final step of aerobic respiration is the Electron Transport Chain

ETC requires oxygen to work

The electron carrier molecules (NADH and FADH2) made in glycolysis and Krebs cycle are used to “power” the production of ATP Up to 34 ATPs can be made

Water is made as a byproduct

Summing up Aerobic Respiration:

Food, usually glucose, is broken down to make energy (ATP) 1 glucose molecule = up to 38 ATP

molecules Oxygen is needed

C6H12O6 + 6 O2 6 CO2 + 6 H2O + ATP +

Heat

If no oxygen is present…

Some cells go through anaerobic respiration aka fermentation

Since oxygen is required for the Krebs Cycle and for the Electron Transport Chain, the only part of cellular respiration that works without oxygen is glycosis which only produces a little ATP

Lactic Acid Fermentation Occurs in muscle cells Turn pyruvate into lactic acid when they

run out of oxygen Lactic acid causes fatigue and cramping

Alcoholic Fermentation Occurs in yeast Turn pyruvate into alcohol Breathe out CO2 – makes bread rise

Examples of Fermentation: