Download Nucleic Acids

Fermentation
Chapter 9
What you need to know!
• The difference between fermentation and
cellular respiration.
Aerobic vs. Anaerobic
• Aerobic = with air
– Aero is Greek for air
– Air = oxygen
• Anaerobic = without air
– An as a prefix means no; An (no) aero (air)
• Aerobic respiration = cellular respiration
• Anaerobic respiration = fermentation
Fermentation
• Glycolysis is the metabolic pathway that
yields ATP during fermentation
– Yields: Write the products of glycolysis here
• Eventually a cell will run out of NAD+
– No more glycolysis
• Fermentation recycles the NADH back into
NAD+
Types of Fermentation
1. Lactic acid fermentation:
–
–
–
–
NADH  NAD+
Pyruvate  lactate (lactic acid)
Causes muscle soreness
Filtered by the liver
2. Alcohol fermentation
– NADH  NAD+
– Pyruvate  CO2 & ethanol (ethyl alcohol)
– CO2 puts bubbles in beer and champagne
and makes dough rise
Types of Fermentation
ATP Yield
• Anaerobic yields 4 ATP during glycolysis
– 2 ATP activation cost
• Net Gain 2 ATP
• Aerobic yields 40 ATP during all 3 steps
– 2 ATP activation cost
• Net Gain 38 ATP
• Aerobic respiration is 19 X’s more efficient
per glucose molecule
Various Metabolisms
• Obligate (strict) aerobes
– Organisms that require oxygen to survive
– Ex: all vertebrates
• Facultative anaerobic organisms
– Can do aerobic or anaerobic cellular respiration
(CR) depending on the situation
– Ex: yeast, muscle cells
• Obligate (strict) anaerobes
– Require oxygen free environment (die in the
presence of O2)
– Ex: deep soil and stagnant pond bacteria
Food
• Not
everything
you eat is
broken down
into glucose
• Fat yields double the ATP of carbs
• Food also provides essential bio-chemicals for
growth