In this lecture you will learn:
the two basic methods of breaking down sugar
for energy, with and without oxygen
the Kreb's cycle
|WITHOUT OXYGEN AKA ANAEROBIC
glycolysis occurs in cytoplasm
1. GLUCOSE (6C) is broken down to (2) 3C
2. Energy is sucked out of the bonds
of the 3C molecules to make an ATP, so net is 2 ATP per glucose
NO OXYGEN - FERMENTATION - anaerobic in
3C is converted to Lactic acid (which
causes stiff and painful muscles)
in yeast 3C is decarboxylated forming
CO2 and Ethanol
wine ... Alcoholic Fermentation
Anaerobic Glycolysis uses only about
7% of available energy<------<<<----
|In both cases of fermentation hydrogens
are added but only in the case of ethanol fermentation is CO2 given off.
Reason why wine can be "bubbly".
|WITH OXYGEN - AEROBIC
KREB'S CYCLE aka CITRIC
1. 3C is transported to mitochondria
2. first CO2 is plucked off to leave 2C
3. then goes into KREBS CYCLE aka The Citric
(3C - CO2 = 2C)
4. the point is to burn the CH to CO2 ..
in the process the hydrogen is dumped onto oxygen –> H2O and to take high
energy electrons (covalent bonds) and suck the energy out of them
to make ATP
– the 2C unit is bound to a 4C unit (oxaloacetate)
to make a 6C unit called CITRIC ACID
(2C + 4C = 6C)
5. As the CO2 are removed, the electrons
are handed off to "handlers" like NAD and the hydrogens come along (NADH).
A total of 2 CO2 are popped off the end regenerating the oxaloacetate 4C
unit ready to take another 2C unit. The NADH now takes the electrons
to the electron transport factory where the energetic electrons are used
to make ATP.
(6C - CO2, 5C - CO2 = 4C)
aka chemiosmosis Click here
6. Now the electrons are handed off to
the electron transport proteins where they use little bits of energy in
turn to push hydrogen ions onto one side of the membrane .. this sets up
a voltage gradient, just like a battery
7. When the voltage gradient is high
enough, the hydrogens can only get across at the ATP synthetase and their
pushing thru results in ADP being phosphorylated to ATP. The hydrogen
now meets up with the oxygen and makes H2O.
RIGHT CLICK and "view image" for full size
Discuss what you know about glycolysis.
What is broken down, into what, how much ATP is made, where does it occur,
who can do this, does it need oxygen?
What are some of the end products of fermentation,
how do these products affect you? What is the purpose of fermentation?
What is the Kreb's cycle? where
does it happen? does it require oxygen? where do the electrons go?
what are the end products of Krebs and electron transport? how much
ATP is made?
Why is oxygen needed for respiration to
How is ATP made? How is electron
transport/respiration like a battery?