Glycolysis and Cellular Respiration

Chapter 8

How do cells get energy?Most cellular energy is stored as ATPCells use glucose to make ATPTwo stages of breaking down glucose

GlycolysisCellular respiration

GlucoseKey energy storage moleculeAll cells use it as an energy sourceGlucose can be stored as either glycogen or

fat

Overview of glucose breakdown1st: glycolysis: begins breakdown of glucose:

breakdown produces 2 molecules of pyruvate. Some ATP is made during this process. It doesn’t require oxygen. These reactions occur in the cytoplasm

If oxygen is available, cellular respiration occur. Two pyruvates are broken down into dioxide and water. This stage produces 34 to 36 ATPs. These reactions occur in the mitochondria

Cont.If oxygen isn’t available then the next step is

fermentation. During this process pyruvate doesn’t enter the mitochondria and it is either converted itno lactate or ethanol and carbon dioxide

What happens during glycolysis Two parts: glucose activation and energy

harvestingBefore glucose can be broken down it must

be activated. This process uses 2 ATPsGlucose is converted to fructose

bisphosphate. This is a highly unstable molecule

Fructose bisphosphate is then split into 2 molecules of glyceraldehyde-3-phosphate(G3P)

Each G3P undergoes a series of reactions that convert it to pyruvate.

Cont.2 ATPs are made for each pyruvate for a total

of 4 ATPs but a net gain of only 22 NADHs are also produced

KNOW page 131!!!!

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