Download Chapter 8.3 zebra

E.Q- Identify the steps of Cellular Respiration &
how the process changes with/without oxygen.
What is Cellular Respiration?
 Respiration is the process of cells making ATP by
breaking down organic compounds which ultimately
releases energy.
Respiration Equation
C6H12O6 + 6O2

6CO2
+ 6H2O + ATP
Glucose + Oxygen  Carbon dioxide + water
+ energy
 Reactants: glucose and oxygen
 Products: carbon dioxide and water and ATP
Glycolysis
 1st step of respiration
 Takes place in the cytosol (cytoplasm)
 Glucose --> 2 molecules of pyruvic acid
 4 ATP’s are produced but 2 were used to
start the process (net gain of 2)
Glycolysis leads to two pathways
Organic Compounds
(glucose)
No oxygen
Glycolysis
Fermentation
(anaerobic
fermentation)
oxygen
Aerobic
Respiration
(krebs / electron
transport)
Kreb’s Cycle --- Aerobic
 Step 2 of respiration
 2 pyruvic acids move
to mitochondria
Kreb’s Cycle - Mitochondria
 Pyruvic acid --> CO2 + acetyl coenzyme A
 Acetyl CoA (or Acectic acid)
 Acetyl CoA enters the Kreb’s cycle and
eventually turns into Citric Acid.
 Kreb’s cycle is also known as citric acid cycle
Kreb’s products
 The net yield from the Krebs
cycle is six CO2 molecules, two
ATP, eight NADH, and two
FADH2.
 Basically --- Kreb’s is
producing energy for
the final step -- electron
transport
Electron Transport
● Final step in the breakdown of glucose happens in
cristae (inner membrane)
 Point at which ATP is produced
● Produces 24 ATP
● Total of 36 ATP’s from one glucose!
Anaerobic pathways
 If there is no Oxygen available after Glycolysis, then
the molecules follow the anaerobic pathway.
 Lactic acid fermentation
 Alcoholic fermentation
Lactic Acid Fermentation
 Pyruvic acid from glycolysis is converted to lactic
acid
 Occurs when muscle cells run low on oxygen
 Cells switch to LA fermentation until oxygen
levels return to normal
 Lactic acid will be converted back to pyruvic acid
(while you breathe hard after exercising)
Alcoholic Fermentation
 ANAEROBIC
 Pyruvic acid is broken down
into alcohol and CO2
 Critical to the success of
bakers and brewers
 Yeast is the main
fermentation tool
 Beer and bread
Cellular Respiration Overview
1. Glycolysis
Glucose - Broken down into two pyruvic acids
(cytoplasm)
2. Krebs cycle ---if oxygen is present
(mitochondria)
2 pyruvic acid  2 Acetyl CoA  Citric Acid
3. Electron Transport
Uses citric acid to make 38 molecules of ATP
( Inner matrix of mitochondria called --- Cristae)
If the cell is lacking O2
2. Lactic Acid Fermentation
Forms lactic acid in cells if NO O2 is present.
Lactic acid returns back to Pyruvic acid once O2 levels return.
OR
2. Alcoholic Fermentation
Pyruvic acid is converted into CO2 & Alcohol.
Cricital to brew beer and bake bread. (yeast)