Anaerobic Respiraiton, Fermentation, and more.....
Campbell Biology in Focus: Chapter 7, Sections 5 and 6
AP Biology 2015 - 2016
I. Anaerobic Respiration: generate ATP using other electron acceptors besides O
2
Final e- acceptors: sulfate (SO
4
), nitrate, sulfur (produces H
2
S)
Eg. Obligate anaerobes: can’t survive in O
2
II. Facultative anaerobes: make ATP by aerobic respiration (with O
2
present) or switch to fermentation (no O
2 available)
Eg. human muscle cells
III. Fermentation = glycolysis + regeneration of NAD +
IV. Comparison of cell options:
Without Oxygen: Fermentation
• Keep glycolysis going by regenerating
NAD +
• Occurs in cytosol
• No oxygen needed
•
Creates ethanol [+ CO
2
] or lactate
• 2 ATP (from glycolysis)
With Oxygen: Aerobic Respiration
• Release E from breakdown of food with
O
2
• Occurs in mitochondria
• O
2
required (final electron acceptor)
•
Produces CO
2
, H
2
O and up to 32 ATP
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V. Types of Fermentation
Alcoholic Fermentation
•
Pyruvate → Ethanol + CO2
• Ex. bacteria, yeast
• Used in brewing, winemaking, baking
Lactic Acid Fermentation
•
Pyruvate → Lactate
• Ex. fungi, bacteria, human muscle cells
• Used to make cheese, yogurt, acetone, methanol
•
There is a great debate about the role of lactate (lactic acid) and muscle fatigue and pain
VI. Various sources of fuel
A. Carbohydrates, fats and proteins can ALL be used as fuel for cellular respiration
B. Monomers enter glycolysis or citric acid cycle at different points
2

VII. Feedback Inhibition of Glycolysis & Aerobic Respiration: Phosphofructokinase
A. Phosphofructokinase is an allosteric enzyme
that controls rate of glycolysis
and citric acid cycle
B. It is inhibited by ATP and citrate (citric acid)
C. It is stimulated by AMP
(Adenosine Monophosphate)
AMP+ P + P → ATP
VIII. Cellular Respiration Overview:
3