In the presence of Oxygen… Aerobic Respiration In the presence of Oxygen…

Quick Quiz: The purpose of photosynthesis is to provide what for the plant cell? The purpose of respiration for BOTH plant and animal cells is to provide what? What is the starting molecule for Respiration? What happens after Glycolysis if there is no O2 available?

Glucose (a monosaccharide!) ATP (the cell’s source of energy) Glucose (continued…) Glucose (a monosaccharide!) ATP (the cell’s source of energy) Glucose Fermentation (anaerobic respiration)

Where does aerobic respiration occur? In the mitochondria! (the “powerhouse” of the cell!)

After Step 1: Glycolysis…. The pyruvic acid joins with an enzyme called Coenzyme A to form Acetyl CoA

Fidgety -- like these guys Acetyl CoA (a “fidgety” molecule) that is not very stable chemically. It enters the Kreb’s Cycle and changes its composition several times producing...

Step 2: Kreb’s Cycle

Products of the Kreb’s Cycle 1) CO2 2) NADH 3) ATP

A word about the products: CO2 is a waste product for animal cells, but is reused in plant cells for… you guessed it- PHOTOSYNTHESIS! NADH is an electron carrier, much like NADPH is in photosynthesis. It carries electrons to electron transport chain ATP- 2 ATP are produced in Krebs Cycle

Step 3: The Electron Transport Chain This ETC is VERY similar to the one in photosynthesis!!!! But where does it occur?

The electron transport chain Electron carrier H+ Phospholipids H+ H+ H+ H+ H+ H+ H+ H+ Caught by Oxygen! Electrons (from NADH) H+

The ETC consists of proteins embedded in the inner membrane of the mitochondrion. H+ is pushed out of the mitochondrial matrix, creating an electrical charge difference similar to the one in the light reactions of photosynthesis. The H+ ions naturally diffuse back through the ATP synthase, creating more ATP for a total of 36!

ATP synthase (an enzyme)uses this energy to make lots of ATP!!!!

The final acceptor of the electron is Oxygen 4H+2O --> 2H2O So at the end of the ETC, WATER is made! So the final products of aerobic respiration are: H2O (from ETC) CO2 (from Krebs cycle) 36 ATP per molecule of glucose