Energy Transformation
in Living Organisms- Cell Process
Cellular Respiration
Energy Connection
Review: Producers
• Producers get their
energy from the sun.
• Producers convert
this light energy into
stored chemical
energy (glucose).
• This process is called
photosynthesis.
Review: 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.
Why Do Cells Need Energy?
Cells Need Energy To:
• move
• change shape
• repair structure
• make new cell parts
• transport food
• expel wastes
The Cells Fuel: ATP
• Adenosine triphosphate = ATP
• Major fuel used for all cell activities
• Food molecules (carbs or fats) are broken down – released
energy is ATP
Food Eaten Release Energy
Energy is stored in
carbohydrates and lipids
Energy release is ATP
Energy (ATP) is used by the
Cells to perform cell activities
D. Cellular Respiration (Process)
a. Process that cells break down
simple food molecules and
release energy
– After you eat, your body
converts carbohydrates
(sugars and starches) into
ATP
– When the body needs
energy (ATP), cells
“withdraw” energy (ATP)
from glucose
b. Occurs in both plants and
animals
• Occurs in the mitochondria
– You breathe for your
mitochondria
Cellular Respiration
c. Converts the food we
eat into energy for the
cell
d. Lots of the energy is
stored in the form of ATP
(fuel for the cell)
e. Most of the energy is
released in the form of
heat… which helps to
maintain a constant body
temperature
e. Produces carbon dioxide
gas
REACTANTS
PRODUCTS
E. Cellular Respiration Chemical
Equation
Raw Materials
C6H1206 + 602
Glucose
Oxygen
Products
6C02 + 6H20 + Energy
Carbon Dioxide
Water
ATP
F. Comparison of the 2 Cell Processes
Cellular Respiration
Photosynthesis
Photosynthesis and Cellular Respiration
*They are opposites!* They both provide energy.
* They form a cycle!
Photosynthesis and Cellular
Respiration Working Together
The BIG Question is…
Do only animals respire?
Or do plants respire too?
• Only plants perform photosynthesis
• Plants AND animals perform cellular
respiration!
(Can you explain why??)
Site of Cellular Respiration
• Both plant and animal cells contain mitochondria:
cell structures that transform chemical energy from
glucose to ATP.
Significant ATP Production
• Aerobic (with oxygen) cellular respiration
releases energy SLOWLY, using oxygen
to convert ONE molecule of glucose to 36
ATP!
Cellular Respiration (anaerobic)
(Without oxygen)
• What happens when cells don’t have enough
oxygen?
• Some organisms live in an oxygen-free
environment. How do they get their energy?
Cellular Respiration (anaerobic)
• Anaerobic respiration is also called
fermentation, or the process by which
energy is released from glucose when
oxygen is NOT available.
• This process allows organisms to continue
to produce energy until oxygen is
available.
• However, this process only releases 2 ATP
per molecule of glucose.
Alcoholic Fermentation
• Anaerobic way of converting energy
for yeast and other
microorganisms
• Glucose broken down to produce
alcohol, CO2 and energy (ATP)
• C6H12O6  ethanol + CO2 + 2 ATP
• EX: baking bread with yeast
fermenting wine & beer
Fermentation - Bread
•
•
•
•
Source of sugar?
DOUGH! (sugar and/or flour)
Yeast use up the O2 and ferment sugar
Produce CO2, which is trapped within
tiny bubbles & results in the dough rising
• Produce ethanol, which evaporates in the
Yeast Cells
baking process
Dough Ferme
Fermentation - Wine
•
•
•
•
•
Source of sugar?
GRAPES!
Yeast use up the O2 and ferment sugar
Produce CO2 (kept only in champagne)
Produce ethanol (% alcohol varies based on
sugar content of grapes and # of
fermentations)
Fermentation - Beer
•
•
•
•
Source of sugar?
BARLEY!
Yeast use up the O2 and ferment sugar
Hops are added as a preservative
and for added flavor
• Produce CO2 and ethanol also
• Various carbohydrates can be used to
make alcohol – including wheat, rice,
and potatoes!
Lactic Acid Fermentation
• Anaerobic way of converting energy in
animal cells and some microorganisms
• Glucose broken down to produce lactic
acid, CO2 and energy (ATP)
• C6H12O6  lactic acid + CO2 + 2 ATP
• EX: muscle cells during strenuous
exercise, fermenting cheese, yogurt, sour
cream
Strenuous Exercise
• Lactic acid is produced by
your muscle cells during
rapid exercise when the body
cannot supply enough O2 to
tissues.
• Without enough O2, the body
is NOT able to produce all of
the ATP that is required.
• The buildup of lactic acid can
cause painful burning in your
muscles!
Minimal ATP Production
• In the absence of oxygen, anaerobic
respiration only releases 2 ATP for each
molecule of glucose broken down.
Comparing ATP Production
• First, your body breaks down glucose through
aerobic respiration to produce 36 ATP per glucose
molecule; however, this is a slow process.
• When muscle cells cannot get enough O2 they break
down glucose through lactic acid fermentation to
produce 2 ATP per glucose…
• Therefore, AEROBIC RESPIRATION is much more
efficient in terms of ATP production –
• 36 ATP compared to 2 ATP!
Aerobic Training
• Ex: long runs, biking, swimming
• Can increase the size and number of
mitochondria in muscle cells
• Can increase the delivery of O2 to muscles by
improving the heart and lungs
Anaerobic Training
• Ex: sprints, strides,
quick bursts of energy
• Increase the glycogen levels in the muscles
• Increase body’s tolerance to lactic acid