Cellular Respiration
What is Cellular Respiration?
The process in which glucose is
broken down and chemical energy
is released for use by cells.
What is Cellular Respiration?
Once the energy that was in sunlight is
changed into chemical energy by
photosynthesis, an organism has to
distribute the chemical energy into a
size (amount) that can be used by cells.
The energy in 1 glucose is distributed to
36 ATP’s
1 glucose = 36 ATP’s
This process is cellular respiration.
Describe Cellular Respiration
• It is a series of reactions where
carbohydrates, mostly glucose, are
broken down to make CO2, water, and
energy (in the form of ATP)
• Takes place in all living things
Cellular Respiration
• Occurs in the
mitochondria of
eukaryotic cells.
• The highly folded
inner membrane
provides a lot of
space for cellular
respiration to occur.
( energy production)
What is the chemical equation
for cellular respiration?
C6H12O6 + 6O2
Glucose + Oxygen
6CO2 + 6H2O + energy
Carbon Dioxide + Water + ATP
Look familiar?
C6H12O6 + 6O2
6CO2 + 6H2O + energy
It is the reverse process of photosynthesis!
ATP
• Most of the energy from
cell respiration is
converted into ATP (a
substance that powers
most cell activities) and
used by the organism.
• Some of the energy is
lost as heat
Cellular Respiration
occurs in 3 stages:
1. Glycolysis
2. The Kreb’s Cycle
3. The Electron Transport Chain
From Food to ATP video
Cellular Respiration
Stage One: Breakdown of Glucose
Glycolysis •Glucose is broken
in half to make
pyruvate.
•This process
produces 2 ATP’s.
Cellular Respiration
Stages Two & Three:
Production of more ATP
•Krebs Cycle
•Electron Transport Chain
These 2 steps only
occur when oxygen
is present. This is called
aerobic respiration.
*aerobic means “in the presence of oxygen”
The Krebs Cycle
• During the Krebs Cycle, the break down of
glucose is continued producing carbon
dioxide in a series of energy-extracting
reactions.
• Net ATP Production is 2 ATP.
Electron Transport Chain
• The E.T.C. is made up of a series of
molecules that transfer electrons from the
original glucose molecule to oxygen.
• After taking the electrons, oxygen then binds
with hydrogen to form water.
• That energy is used to create 32 ATP’s.
Totals
•
•
•
•
Gycolysis 2 ATP
Krebs Cycle 2 ATP
Electron Transport Chain 32-34 ATP
Total = 36-38 ATP
Comparing Photosynthesis &
Respiration
Photosynthesis
Cellular Respiration
Function
Stores Energy
Releases Energy
Location
Chloroplasts
Mitochondria
Uses
Carbon dioxide & Glucose & oxygen
water
Glucose & oxygen Carbon dioxide &
water
Produces
Equation
6CO2 + 6H2O 
C6H12O6 + 6O2
C6H12O6 + 6O2
6CO2 + 6H2O
Cellular Respiration
Cellular Respiration requires oxygen.
It is an aerobic process.
What happens when oxygen is not present?
•Fermentation will then occur.
•Not much ATP is produced but it does
allow the break down of glucose to
continue.
Fermentation
• There are two types of
fermentation:
alcohol and lactic acid.
• Alcohol fermentation is done by
yeasts. It produces alcohol &
carbon dioxide.
• Lactic Acid is produced by
muscles during rapid exercise
when the body cannot supply
enough oxygen – causes a burning
sensation in the muscles.
Comparing Photosynthesis &
Respiration
Photosynthesis
Cellular Respiration
Function
Stores Energy
Releases Energy
Location
Chloroplasts
Mitochondria
Uses
Carbon dioxide & Glucose & oxygen
water
Glucose & oxygen Carbon dioxide &
water
Produces
Equation
6CO2 + 6H2O 
C6H12O6 + 6O2
C6H12O6 + 6O2
6CO2 + 6H2O
Photosynthesis/Cellular
Respiration Connection
Describe
the path
energy
takes
C6H12O6 + O6
Describe
the path
carbon,
oxygen,
and
hydrogen
take
Read how photosynthesis &
respiration are related:
http://www.usoe.k12.ut.us/curr/science/scib
er00/8th/energy/sciber/photosyn.htm