Chapter 9
Cellular Respiration
Review
 What
is the equation for photosynthesis?
 What are the two reactions for photosynthesis?
Where do they occur?
Cellular Respiration
 Location:
Mitochondria (powerhouse of the cell)
 Purpose: Turn chemical energy (food) into usable
energy (ATP)
 Chemical Equation:
C6H12O6 + 6 O2 6 CO2 + 6 H2O
 Who needs this?: Eukaryotes
3 stages of Cellular Respiration in
order
Glycolysis
Krebs
Cycle
Electron Transport Chain
Glycolysis (stage one)
Means: Split glucose
 Location: cytoplasm
 Reactants (Input): Glucose
 Products (Output): 2ATP and Pyruvates

Note: pyruvates are often called pyruvic acid
Krebs or Citric Acid Cycle
Only occurs if oxygen
is available (aerobic
process)
 Location: Mitochondria
 Reactant: Pyruvate and
oxygen
 Product: 2ATP and CO2

Electron Transport Chain
Location: Mitochondria
 Reactant: Oxygen
 Oxygen acts as an
electron receptor.
 Product: 32 ATP and
H2O

Simplified Cellular Respiration Equation
C6H12O6 + 6 O2 6 CO2 + 6 H2O


How many ATP’s are created from one glucose
molecule? 36
What is the relationship between photosynthesis
and cellular respiration?
Relationship

Opposite processes
Relationship


Photosynthesis is about
energy capture where
cellular respiration is
about energy release.
36% of energy from
glucose is given off as
ATP which leaves 64%
given off as heat.
Review
 What
is the equation for cellular respiration?
 What are the three reactions for cellular
respiration? Where do they occur?
 What are all the inputs for cellular respiration?
 What are all the outputs for cellular respiration?
 What is the relationship between photosynthesis
and cellular respiration?
Fermentation
What is fermentation?

In the absence of oxygen there
is no cellular respiration,
fermentation occurs and small
amounts of ATP (energy) will
be created in order to keep
the cell from dying.
Two kinds of fermentation

Lactic Acid Fermentation

Alcoholic Fermentation
Lactic Acid Fermentation


Produces lactic acid and 2 ATP
Example:
 Muscle
Cells: Fermentation occurs during heavy exercise
 Bacteria: Some help to make yogurt and cheese
Alcoholic Fermentation


Produces alcohol, carbon dioxide, and 2 ATP
Example:
 Bread/yeast:
This process causes bread dough to rise and
the carbon dioxide released causes the holes in bread.
 This is how alcoholic beverages are created.
Energy/Exercise

Short, quick bursts of energy
 Body
uses ATP already in muscles as well as ATP
made by lactic acid fermentation.
 Once finished with exercise you “huff and puff” for
several minutes to pay back the built up “oxygendebt” and clear the lactic acid from the body.
Energy/Exercise

Longer exercises
Fermentation only makes enough energy to last 90
seconds
 Exercise longer than this can only get the energy it needs
from cellular respiration.
 The body stores energy in the form of the carbohydrate
glycogen. These glycogen stores are enough to last for
15 to 20 minutes of activity. After that, the body begins
to break down other stored molecules, including fats, for
energy. This is how animals can hibernate by living off of
stored fats.

Review
 When
does fermentation occur?
 What are the two types of fermentation?
 For each type:
 What
are the inputs?
 What are the outputs?