Cellular Respiration
Producers



Producers get their
energy from the sun.
Producers convert this
light energy into
stored chemical
energy (glucose).
This process is called
photosynthesis.
Consumers



Consumers get their
energy from the
producers.
Consumers convert
stored chemical
energy (glucose) into
usable chemical
energy (ATP).
This process is called
cellular respiration.
Cellular Respiration (aerobic)

Cellular respiration is the process by which
glucose (C6H12O6) is broken down to
release energy for making ATP, another
form of chemical energy.
Aerobic Respiration – Equation
C6H12O6 + 6 O2
oxygen
food
(glucose, a carbohydrate)
6 H2O + 6 CO2 + ATP
water
carbon
dioxide
Photosynthesis:
6 H2O + 6 CO2 + energy (sun) → C6H12O6 + 6 O2
Aerobic Cellular Respiration:
C6H12O6 + 6 O2 → 6 H2O + 6 CO2 + energy (ATP)
The BIG Question is…
Do only animals respire?
Or do plants respire too?
Only plants perform photosynthesis
 Plants AND animals perform cellular
respiration!

Site of Cellular Respiration

Plant and animal cells contain mitochondria: cell
structures that transform chemical energy from
glucose to ATP.
Significant ATP Production

Aerobic cellular respiration releases energy
SLOWLY, using oxygen to convert ONE
molecule of glucose to 36 ATP!

36 ATP = 263 kilocalories
Cellular Respiration
 process
that releases energy by
breaking down glucose molecules in
the presence of oxygen.
 6O2 + C6H12O6 → 6CO2 + 6H2O + Energy
oxygen + glucose → carbon dioxide + water + energy
3 Stages make up Cellular Respiration
Glycolysis
 Kreb’s Cycle
 Electron Transport

1st Stage of Cellular Respiration

Glycolysis –1 molecule of glucose is broken in half,
producing 2 molecules of pyruvic acid (pyruvate) + 2
ATP molecules
 10 step process that uses enzymes along the way!
 Pyruvic
acid is a 3 carbon molecule
 O2
present - it is followed by the Kreb Cycle & the
electron transport chain.
 O2
not present (anaerobic) - it is followed by
fermentation.
Section 9-1
Glucose
Glycolysis – occurs in
the cytoplasm of a cell
2 Pyruvic acid
Carries energy from glucose bonds in
the form of high energy electrons
Input - C6H12O6 and NAD+ (helper molecule) and ADP
Output – 2 ATP(net) + 2 Pyruvic Acid (Pyruvate) and NADH
2nd Stage of Cellular Respiration

Kreb Cycle – requires O2
(aerobic)
 Occurs
in mitochondrial matrix
 Pyruvic
acid (pyruvate) is
broken down into CO2 which is
released into the air.
 Molecules
made to carry highenergy electrons to the electron
transport chain
The Krebs Cycle
Citric Acid
Production
Inputs - Pyruvic Acid
(NAD+, FAD, ADP, CoA)
Outputs – CO2 + 2 ATP +
CoA and high energy electron
carrying products (NADH,
FADH2)
NAD+ , FAD and CoA helper
molecules
3rd Stage of Cellular Respiration

Electron Transport – uses high-energy electrons
from the Krebs cycle to make ATP. Majority of ATP
comes from this stage!
 Occurs in the membrane of mitochondria
 Inputs
 O2,
(NADH, FADH2 from Kreb’s Cycle – contain
the energy from the glucose molecule)
 Outputs
 ATP + H2O
Electron Transport Chain
Input – O2 and (NADH, FADH2 )
Output – ATP, H2O (NAD+, FAD)
Electron Transport
Hydrogen Ion Movement
Channel
Intermembrane
Space
ATP synthase
Inner
Membrane
Matrix
Electron Transport Chain
Concentration gradient (of H ions) provides the
Potential Energy to produce ATP via the enzyme
ATP synthase
Cellular Respiration (aerobic)

Glucose + O2 
Glycolysis + Krebs + Electron Transport
ATP +CO2 + H2O
Cellular Respiration Inputs and Outputs
Stage
Glycolysis
Kreb’s Cycle
Electron
Transport
Chain
Occurs in
this Location
Cytoplasm
Mictocondria
Matrix
Inputs
C6H12O6 (glucose) 2 ATP + 2 Pyruvic
Acid + NADH
2 Pyruvic Acid 2 ATP + CO2 +
NADH + FADH2
Output Totals
2 ATP
2 ATP + CO2
NADH
Mitochondrial
Membrane
+ FADH2 + O2
C6H12O6 + O2
TOTALS
Output
(intermediat
e)
32-34 ATP +
H2O
32-34 ATP +
H2O
H2O + CO2 +
36-38 ATP
(energy)
Electron
Transport Chain
Comparing Photosynthesis &
Cellular Respiration
Photosynthesis – removes CO2 & puts O2 back into air.
6CO2 + 6H2O + light(energy)→C6H12O6 + 6O2
Cellular Respiration – removes O2 & puts CO2 back into air.
6O2 + C6H12O6 → 6CO2 + 6H2O + Energy (ATP)
Respiration and Photosynthesis are
OPPOSITE reactions
Photosynthesis – in chloroplasts
Sunlight (Energy)
Oxygen (O2)
Glucose (C6H12O6)
Water (H20)
Carbon Dioxide (CO2)
Respiration – in mitochondria
Oxygen (O2)
ATP – (Energy)
Water (H20)
Glucose (C6H12O6)
Carbon Dioxide (CO2)
Sunlight
(Energy)
ATP –
(Energy)
Oxygen (O2)
Oxygen (O2)
Water
(H20)
Glucose
(C6H12O6)
Carbon
Dioxide
(CO2)
Glucose
(C6H12O6)
Respiration/Photosynthesis
Cellular Respiration (anaerobic, No
O2 is present) - Fermentation
Energy is released from glucose when oxygen
is NOT available.
 allows organisms to continue to produce
energy until oxygen is available.

2 Types of Fermentation

Lactic Acid fermentation – in muscles during
rapid exercise when the body can’t supply
enough O2 to the tissues; without oxygen, the
body isn’t able to produce the ATP required.
 Buildup

causes pain & soreness.
Alcoholic fermentation – yeasts & a few other
microorganisms; causes bread dough to rise.
Lactic Acid Fermentation
No O2 is present
 Kreb’s Cycle and Electron transport chain
can’t proceed
 Glucose  lactic acid + 2 ATP
 EX: muscle cells during strenuous exercise
fermenting cheese, yogurt, sour cream

Domino effect




a lack of oxygen, the electron transfer chain cannot pass on their
electrons Oxygen
Electron transfer chain cannot accept electrons from NADH and
FADH2 (from Kreb’s cycle)
electron carriers are locked holding onto electrons, causing a
depletion of NAD+ and FAD+
Neither Kreb’s cycle or glycolysis proceeds.
Lactic Acid Fermentation
Glucose
Pyruvic acid
2 ATP + Lactic acid are produced
Lactic acid
Alcoholic Fermentation
No O2 present
 Energy for yeast and other microorganisms
 Kreb’s cycle and Electron transport chain
don’t proceed
 Glucose  ethanol + CO2 + 2 ATP
 EX: baking bread with yeast, fermenting wine
& beer

Fermentation vs. Respiration

Respiration
 Produces
CO2 + H2O + 36 to 38 ATP
 Process includes Glycolysis, Kreb’s cycle and
Electron Transport chain

Fermentation
 Produces
CO2 (in alcoholic only) and 2 ATP
 Process includes Glycolysis followed by Fermentation
 Breaks glucose into lactic acid or ethanol