Glycolysis & Cellular Respiration

(Reference Chapter 8)

The Purpose

• Convert the energy in organic molecules into a usable form (ATP)• ATP can then be

used for work

Remember: food molecules contain more energy than most cells need to power their processes. So,

food molecules are broken down to make many molecules of ATP.

Who Goes Through Respiration?• All living organisms go through some sort of

cellular respiration (though many do not use the complete process) to make ATP

• Plants still go through cellular respiration!

The Two Types

Aerobic Respiration

• Requires oxygen• Fully breaks down

glucose to CO2 and makes LOTS of ATP

• Requires mitochondria

Anaerobic Respiration

• No oxygen needed• Glucose only

partially degraded• Makes small

amounts of ATP more quickly

• No mitochondrial involvement

In Eukaryotic Cells (no bacteria no viruses)• Fuel + Oxygen + ADP + P Carbon Dioxide + Water

+ ATP

• 3 stages, 2 of which take place in the mitochondria

• Remember Cellular Respiration is why we inhale O2 & exhale CO2.

• Oxygen picks up the left-over electrons & H+ at the end of the Electron Transport Chain. If we don’t have oxygen the whole thing backs up & stops.

• Carbon Dioxide is a waste product created in the Krebs Cycle when H+ & electrons are stripped off the product of glycolysis called pyruvic acid.

Random Facts• Every cell contains on average about a billion ATP

molecules• We have at any time about 1 sextillion

(100,000,000,000,000,000,000,000) ATP molecules in our body

• We use all of them in minutes and must regenerate them• The average ATP molecule is made and degraded 3 times

per minute• We go through about 20 pounds worth of ATP every hour

1st Stage is Glycolysis:

• This step occurs in the CYTOPLASM of the cell & does not require OXYGEN.

• The product moves to mitochondria when oxygen is present.

2nd Stage is Krebs Cycle

Occurs in the MITOCHONDRIA W/ Oxygen- The leftover molecule from glycolysis moves

into the mitochondria by the process of DIFFUSION.

-Its Bonds are broken & electrons are stripped & taken to the next step.

-Carbon is released as CO2 (this is why we exhale CO2!!!)

3rd Stage is The Electron Transport Chain

-In the inner membrane of the mitochondria-Uses oxygen-Gives mitochondria its reputation as the “power

house” of the cell: A LOT of ATP is produced during this step

-Electrons & H+ moving around eventually causes the creation of ATP.

Oxygen’s role is to accept the stripped electrons & combines with hydrogen ions to form WATER.

– If you don’t have oxygen you cannot “clean up” the electrons & H+ & the process comes to a halt. Then you cannot produce enough ATP…and then your cells will die.

– Enough cell death & then you’ll die