Cellular Respiration
Takes place in the cells of
both plant and animals
Respiration
Respiration – A process by which cells obtain
energy from glucose. Cells break down simple
sugar and release the energy they contain.
This is a continuous process – all plant and
animal cells need energy! They must Respire!
When you eat, you add to your body’s energy
“savings account.” When cells need energy, they
“withdraw” it by breaking down sugar/carbs.
Like Photosynthesis, Respiration takes place in
two (2) stages:
1. Stage one – takes place in cytoplasm.
Molecules of glucose are broken down. No
oxygen is involved.
2. Stage two –takes place in the Mitochondria.
Small molecules broken down to even
smaller molecules. Oxygen used! Lots of
energy is released here – “powerhouse of
cell.” Remember, “I lift things up and put
things down…”
• The products in stage two are carbon dioxide
(CO2) and Water (H2O.)
• So…the raw materials for Respiration are:
• Glucose (sugar) and Oxygen
• The products are: Carbon Dioxide and Water
• Do you notice anything similar to
Photosynthesis??
• Well….the raw materials used for Respiration
(glucose and Oxygen) are the same as the
products created in Photosynthesis.
• And… the raw materials used in
Photosynthesis (carbon dioxide and water) are
the same as the products created in
Respiration.
• Remember the chemical Equation for
Photosynthesis is:
• 6 CO2 + 6 H2O -- C6H12O6 + 6 O2
• The chemical equation for RESPIRATION is:
• C6H12O6 + 6 O2---6 CO2 + 6H2O
• They are OPPOSITE processes that form a
cycle to keep the level of Oxygen and Carbon
dioxide constant on Earth.
• Respiration uses 02. Photosynthesis uses
CO2.
• Some cells can get energy from food without
using Oxygen
• Fermentation – energy for cells without using
oxygen.
• Alcoholic Fermentation – yeast breaks down
sugar. Alcohol and CO2 are products. CO2 in
dough creates air bubbles in bread or bubbles
in beer.
• Lactic Acid Fermentation- muscles run out of
oxygen, so lactic acid supplies cells with
energy. (sore muscles = pain = lactic acid was
supplied to muscle cells since Oxygen ran out.)
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Cells get energy from glucose
They do it in two (2) steps
They use oxygen
They release energy