ATP and Cellular Respiration
• Breakdown of a Glucose Molecule to make ATP so our
cells can perform chemical reactions
THE BASICS OF CELLULAR RESPIRATION
• Heterotrophs – organisms that cannot make their
own energy and need to consume other organisms
to get energy (consumers)
– All animals, fungi, and some bacteria are heterotrophs
Why Make ATP?
• Referred to as energy currency of the cell
• Provide energy for chemical reactions to take place
in our body (cells)
Mitochondria
• Site of cellular respiration (where ATP is made)
• Conists of
– Outer membrane
– Inner membrane
– Matrix
– Cristae
Cellular Respiration Breakdown
• Glycolysis
– Located in cytoplasm of
cell
• Krebs Cycle
– Located in Mitochondrial
Matrix
• Electron Transport Chain
– Located in mitochondrial
cristae
Glycolysis
• Breakdown of a single
Glucose molecule
• Reactants
– Glucose molecule
• Products
– 2 pyruvate molecules
– 2 ATP molecules
• Energy
– 2 NADH molecules
• Electron carriers
Pyruvate
• Pyruvate can take 2 paths
from this point:
1. Aerobic Respiration
(with oxygen)
– Pyruvate moves into
mitochondria and ATP is
made via Krebs Cycle and
Electron Transport Chain
2. Anaerobic Respiration
(without oxygen)
– Pyruvate stays in
cytoplasm and is
converted into lactic acid -Lactic Acid Fermentation
Aerobic Respiration
• Krebs Cycle
– Conversion of 2 pyruvate
molecules
• Reactants
– 2 pyruvate molecules
• Products
– 4 CO₂ molecules
– 2 ATP molecules
• Energy
– 6 NADH molecules
• Electron carriers
– 2 FADH₂
• Electron carriers
Aerobic Respiration
• Electron Transport Chain
– Electrons are transferred to proteins from NADH and
FADH₂
– Electrons are passed from one protein to the next
– Final electron acceptor is Oxygen (O₂)
• Reactants
– NADH
– FADH₂
• Products
– 34 ATP molecules
• Energy
– Water (H₂O)
Anaerobic Respiration
• Lactic Acid
Fermentation
– Conversion of 2
molecules of pyruvate
into lactic acid when
oxygen is not present
– Happens during
vigorous muscle
exercise
– Liver converts lactic
acid back into glucose
Anaerobic Respiration
• Alcohol Fermentation
– Does not occur in
humans
– Occurs in yeast when
oxygen is not
available
• Facultative anaerobes
– Conversion of 2
molecules of
pyruvate into ethanol
Photosynthesis and Cellular Respiration