Ch. 8.3 Guided Notes – Cellular Respiration
Cellular Respiration is the process of breaking down ___________
molecules to obtain __________ for the cell. It is a ___________
process. It occurs in the _______________ of ____________ and
__________. Plants break down the ______________ they made for
energy later.
Two Stages
A) ____________ Respiration – does not require ___________
1. Glycolysis
B) __________ Respiration – requires oxygen to take place
2. Krebs Cycle
3. Electron Transport Chain
1. Glycolysis
Glucose is broken down into ____________. It requires energy
(____) to start glycolysis. Glycolysis makes 4 ATP. (Used 2, so a net
gain of only 2 ATP)
2. Krebs Cycle
Pyruvate is transported inside the ______________. Oxygen is
needed for this to take place. It is broken down into ____ ATP, ___
CO2, _____NADH, and ____ FADH2.
3. Electron Transport
The ____________ from _______ and _________ are used to make
ATP. Makes 34 ATP.
Cellular Respiration makes a total of 38 ATP. (Two from __________
respiration and 34 from __________ respiration.)
Anaerobic Respiration
When there is not enough ___________ for the Krebs Cycle and
Electron Transport to take place, ___________ occurs instead. NAD+
is _________ and __________ repeats over and over. It only makes
2 ATP for each ___________ molecule.
This happens in your body when your _________ use up the oxygen
supply. ____________ is converted into ___________ acid. You feel
this as burning if you run hard.
_______ can break down pyruvate into _______ alcohol when they
do not have enough oxygen.
Summary
 Organisms use cellular respiration to break down glucose
(catabolic pathway)
– It’s photosynthesis in reverse!
 The stages of cellular respiration are:
1. Glycolysis (anaerobic)
2. Krebs Cycle (aerobic)
3. Electron Transport (aerobic)
 In the absence of oxygen, cells can repeat glycolysis over and
over by fermentation. It only makes 2 ATP for each glucose vs.
38 ATP for each glucose if it went onto the Krebs Cycle and
Electron Transport.
Reactants
Products
Glycolysis
(anaerobic)
Krebs Cycle
(aerobic)
Electron Transport
(aerobic)
1.
Oxygen!
Oxygen
Present?
2.
3.
2.
No
Oxygen