Transcript Cellular Respiration

Cellular Respiration
Cellular Respiration
 Both autotrophs and heterotrophs use the
compounds in food for energy sources.
 Autotrophs make their own glucose.
 Heterotrophs cannot.
 The process by which glucose molecules
are broken down to release energy (ATP) is
cellular respiration.
Cellular Respiration
 The process by which glucose molecules
are broken down to release energy is
cellular respiration.
 It is a series of chemical reactions that
produces ATP. Most cellular processes use
ATP for energy.
Two types of Respiration
 There are two types of cellular respiration.
 Aerobic - requires oxygen
 Produces 36 ATP from each glucose
 Anaerobic - takes place without oxygen
 Produces 2 ATP from each glucose
Anaerobes
 Anaerobes are organisms that use the
anaerobic respiration pathway.
 Most anaerobes are bacteria.
 Anaerobes do NOT require oxygen.
Aerobes
 Aerobes are organisms that use the aerobic
respiration pathway.
 Aerobes require oxygen.
Stages of Respiration
 The first stage of respiration for all living
organisms, anaerobes or aerobes, is called
glycolysis and it takes place in the cytosol.
Glycolysis
 Glyco means “glucose/sugar”
 Lysis means “to split”
  glycolysis means “to split
glucose”
Glycolysis
Glucose
C6H12O6

Two pyruvate (3-C) molecules
Two ATP
Two NADH
Stages of Respiration
 The second stage in aerobic respiration is
the Krebs cycle, which occurs in the
mitochondria.
 Pyruvate is converted to Acetyl-CoA, which
enters the Krebs cycle. The Acetyl-CoA is
broken down to form CO2, ATP, NADH,
and FADH2.
Stages of Respiration
 In the Krebs cycle, the pyruvate is
converted to acetyl-CoA, which is broken
down to form CO2, ATP, NADH, and
FADH2.
 One ATP is produced for each pyruvate.
 CO2 is a byproduct.  why we breathe out
carbon dioxide!
Stages of Respiration
 So, after glycolysis and the Krebs cycle,
there are 4 ATP produced from each
glucose.
 There’s still 32 ATP left to get from the
process (because aerobic produces a total of
36 ATP from each glucose).
Electron Transport Chain
 The rest of the energy is contained in
electrons carried by NADH and FADH2.
 Electron transport is the process by which
energy is transferred from NADH and
FADH2 to ATP. This phase is also in the
mitochondria.
Aerobic Respiration
 C6H12O6 + 6O2 
glucose
oxygen
6CO2 + 6H2O + energy
carbon
water
ATP
dioxide
Aerobic Respiration
 Compare the reactants and products of
photosynthesis and cellular respiration.
 The reactants of one process are the
products of the other!
Anaerobic Respiration
Anaerobic respiration does NOT require oxygen.
The 2 most common forms are:
Alcoholic fermentation
Lactic acid fermentation
Alcoholic Fermentation
 Is carried out by yeast, a kind of fungus
 Does not require oxygen
 Uses only glycolysis
 Pyruvate + NADH  Ethanol + NAD+ + CO2
Alcoholic Fermentation
 Uses:
 Baking
 Wine and beer industry
 Ethanol
 Swiss cheese
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Lactic Acid Fermentation
 Uses only glycolysis
 Does not require oxygen
 Pyruvate + NADH  Lactic Acid + CO2
Lactic Acid Fermentation
 Carried out by human muscle
cells when they are oxygendeprived.
 Lactic acid is a toxin and
causes fatigue, soreness, and
stiffness in muscles.
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