fermentation. atp - adenosine triphosphate atp is “spring-loaded” the phosphates have a negative...
Post on 31-Dec-2015
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ATP is “spring-loaded”
• The phosphates have a negative charge –repel each other• This means
potential energy is stored in the bonds
Aerobic Respiration
• The oxygen is electronegative and pulls the electrons down the ETC• Without it, no oxidative
phosphorylation happens
NAD+ regeneration
• To keep cycling glycolysis, we need NAD+ to be in sufficient supply• This is done by
transferring the electrons from NADH back to pyruvate
Fermentation
• Glycolysis still happens – NAD+ oxidizes glucose to 2 pyruvate• No ETC, so no 32 ATPs• Fermentation cycles
glycolysis again and again
Two types
Alcohol Fermentation• Pyruvate is converted to
ethyl alcohol (ethanol)• Yeast – used for bread,
wine, beer
Lactic Acid Fermentation• Pyruvate is converted to
lactate (ionized form of lactic acid)• Fungi and bacteria –
used for cheese and yogurt• Humans – in our muscle
cells
Which is better?
Aerobic Respiration
• 19 times as much ATP • 38 ATP per glucose
38 x 7.3 kcal/mol = 277.4 kcal
Fermentation
• 2 ATP per glucose
2 x 7.3 kcal/mol = 14.6 kcal
Two types of anaerobes
Obligate anaerobes• Can only do
fermentation or anaerobic respiration
• Can’t survive in the presence of oxygen
Facultative anaerobes• Can do both
• Our muscle cells behave this way
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