Transcript What about cells that cannot convert sunlight?

Cellular Respiration
&
Fermentation
Aerobic Cellular Respiration

The process that involves oxygen and
breaks down food molecules to release
useable energy….ATP!!!

Cellular Respiration happens in 3 steps



1. Glycolysis
2. Krebs Cycle
3. Electron Transport Chain
Cellular Respiration

Creates 34-38 molecules of ATP
The Chemical Pathways
Cellular Respiration Flow
Glucose
O2
Present
Glycolysis
Krebs
cycle
Electron
transport
No O2
Present
Fermentation
(without oxygen)
Alcohol or
lactic acid
What is Cellular Respiration?
Respiration Equation
C6H12O6 + 6 O2
6CO2 + 6H20
***NoTiCe: This is the reverse
equation for photosynthesis
MUST HAVE OXYGEN PRESENT!
Where does Cellular Respiration Happen?
Electrons carried in NADH
Pyruvic
acid
Glucose
Glycolysis
Cytoplasm
Krebs
Cycle
Electrons
carried in
NADH and
FADH2
Electron
Transport
Chain
Mitochondria
Photosynthesis and
Cellular Respiration

The products of one reaction are the
reactants of the other reaction.
Photosynthesis
Cellular Respiration
Sunlight
energy
Ecosystem
Photosynthesis
(in chloroplasts)
Cellular respiration
(in mitochondria)
Useable energy
Heat energy
Glycolysis
Anaerobic Conditions
(No oxygen)
Aerobic Conditions
(Oxygen present)
Fermentation
Respiration
Krebs Cycle
&
Electron Transport Chain
Under Anaerobic Conditions

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Fermentation
occurs in cells where
oxygen can be a
toxic element or is
not present.
NO O2 present!
“No O – No go!”
(into Krebs
Cycle/ETC)
2 Types of Fermentation

If there is no
oxygen, the
pyruvate formed
during glycolysis
will be broken
down again to
either lactic acid
or ethanol
Lactic Acid Fermentation

Lactic acid Fermentation – fermentation
that produces lactic acid
Pyruvic acid + NADH  lactic acid and NAD+

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The NAD+ helps provide energy to keep
glycolysis going.
Occurs mostly in animals muscle cells &
some bacteria
Lactic acid burns! Muscles hurt!
Lactic Acid Fermentation
 IN:
 Pyruvic
Acid
 NADH
 OUT:
 Lactic
 NAD+
Acid
2 ADP+ 2
Glycolysis
2 NAD
2 NAD
Glucose
(a) Lactic acid fermentation
+ 2 H
2 Pyruvic
acid
2 Lactic
acid
Alcoholic Fermentation

Alcoholic fermentation – fermentation
that produces alcohol
Pyruvic acid + NADH  alcohol + CO2 + NAD+

Occurs in yeast and a few other
microorganisms
Alcoholic Fermentation

IN
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Pyruvic acid
NADH
OUT
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Alcohol
CO2
NAD+
What form does
CO2 take?
That’s right…gas!
& when there is gas
in liquids we see….
BUBBLES 
2 CO2 released
2 ADP+ 2
2 ATP
Glycolysis
2 NAD
Glucose
(b) Alcoholic fermentation
2 NAD
2 Pyruvic
acid
+ 2 H
2 Ethyl
alcohol
Fermentation

Process of energy production in
the absence of oxygen
 Glycolysis and fermentation
together only produces 2 ATP.
 This is not efficient!!
Why Fermentation?

It does not produce
usable energy…ATP
so why bother?
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NADH is converted
to NAD+
NAD+ is needed for
glycolysis