Respiration is the process by which organisms produce energy from food. There are two types: aerobic respiration uses oxygen to fully break down glucose, producing much energy as carbon dioxide and water. Anaerobic respiration breaks down glucose without oxygen, producing less energy as ethanol, lactic acid or carbon dioxide. Both are important - aerobic respiration powers most cell functions while anaerobic respiration allows functions like leavening bread or muscle movement without oxygen.

1. Discuss the importance of
respiration:
•Aerobic
•Anaerobic
•Importance
of respiration
By: Hubert Pascual

2. Energy
• The first law of thermodynamics states that
energy can be changed from one form to
another, but it cannot be created or
destroyed. The total amount of energy and
matter in the Universe remains constant,
merely changing from one form to another.
By: Hubert Pascual

3. • Respiration is the chemical breakdown of
food molecules in the cells to produce
energy.
• It can also be stated as the process by which
the energy in food is made available for cells
to do work necessary to keep it alive. In this
process, energy is released which is used for
the body reactions needed to live and grow.
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Definition of Respiration

4. Two Types of Respiration
• Aerobic respiration- when oxygen is used in a
reaction, this process is catalyzed by enzymes and
is also called cellular, internal or tissue
respiration. (Where food molecules are broken
down using oxygen)
• Anaerobic respiration- occurs without oxygen.
Both anaerobic and aerobic respiration both
involves the breakdown of glucose, however in
anaerobic respiration it is not completely broken
down. (Where food molecules are broken down
without using oxygen)
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6. • The normal process of respiration takes place in the
presence of oxygen and produces a large amount of
energy.
• In plants, substance such as glucose are transported
to all the living cells. This food may have recently
been made during photosynthesis, or it may be food
brought out from the storage organs.
• In animals (for example Humans) the food which we
eat is digested and then taken by blood to all the
living cells in the body.
About Aerobic Respiration
By: Hubert Pascual

7. About Aerobic Respiration
• In the cells of plants and animals a series of
chemical reaction takes place under the control
of enzymes in various small structures called
mitochondria. Mitochondria are also called the
power house of the cell because it stores and
provides energy. Oxygen combines with the
respiratory substrate such as glucose, release a
large amount of energy and produces carbon
dioxide and water.
• Glucose + Oxygen + Energy + Carbon dioxide + Water {Word
Equation}
• C6H12O6 + 6O2 ---> Energy + 6CO2 + 6H2O { Chemical Equation}
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Aerobic Respiration

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Aerobic Respiration

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11. About Anaerobic Respiration
• Anaerobic respiration takes place when there is
no oxygen. It also consist of series of chemical
reactions under the control of enzymes, but the
respiratory substrate (glucose) is only partly
broken down and releases only a small amount of
energy. Anaerobic respiration releases less energy
from a given quantity of food than aerobic
respiration.
• In plants, such as germinating seeds, and in yeast,
anaerobic respiration leads to the production of
ethanol, carbon dioxide and a small amount of
energy.
By: Hubert Pascual

12. • In animals (for example in our muscles) when their is
insufficient oxygen for aerobic respiration, anaerobic
respiration produces lactic acid. This causes the muscle
to feel fatigued. This is what happens when athletes
sprints without taking breath. Lactic acid builds up in the
muscles and makes them ache.
In plants and yeast
• Glucose ---> Energy + Ethanol + Carbon dioxide
In animals:
• Glucose ---> Lactic acid + Energy
• Aerobic respiration takes place in the mitochondria while
anaerobic respiration takes place in the cytoplasm.
About Anaerobic Respiration
By: Hubert Pascual

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14. • Making bread- In bread making the reaction of anaerobic
respiration of sugar and yeast produces carbon dioxide. It is
the pockets (bubbles) of carbon dioxide gas that makes the
bread light, soft and fluffy. The yeast breaks down the sugar
by means of anaerobic respiration or fermentation to release
carbon dioxide, ethanol and energy.
• Making alcoholic drinks- When making alcoholic drinks we
make use of the fact that in the anaerobic respiration of
sugar, yeast produces alcohol (ethanol). For example, beer is
made by means of anaerobic respiration (fermentation) of
hops, while wines of grapes or various fruits of any kind are
made through fermentation.
• Anaerobic respiration of bacteria, which forms lactic acid, is
used to make cheese, yogurt and sour cream. The lactic acid
gives these foods a characteristic sour taste.
By: Hubert Pascual
Importance of Anaerobic Respiration

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Anaerobic Respiration
Yeast in bread
Air pockets in bread caused by Carbon dioxide

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Anaerobic Respiration
Yeast in whine
making

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Anaerobic Respiration

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Anaerobic Respiration

19. Lactic Acid Fermentation
• Occurs in animal
cells when oxygen
is not present.
• Lactic acid is
produced as a by-
product of
producing ATP
without oxygen.
By: Hubert Pascual

20. Comparison of Aerobic and Anaerobic
Respiration
By: Hubert Pascual
Aerobic Respiration Anaerobic Respiration
Complete breakdown of glucose Incomplete breakdown of glucose
Produces large amount of energy Produces small amount of energy compared
Needs oxygen No oxygen required
Products of carbon dioxide and oxygen
Products are alcohol and carbon dioxide (in
yeast) or lactic acid (in muscles)
Reaction takes place in mitochondria of cell
Reaction takes place in the cytoplasm of
cells

21. Review Questions?1. What is respiration?
2. What is aerobic respiration?
3. What are the products of aerobic respiration?
4. Why is it that more energy is given off during aerobic
respiration than anaerobic respiration?
5. State three differences between aerobic and anaerobic
respiration.
6. Which gas is produced as yeast respires? How do you know?
7. What type of respiration occurs in a germinating bean seed?
8. What type of respiration goes on in your body if you are
running very fast?
9. Both types of respiration occurs in the cells of the organism.
State the actual site of the reactions for each type of
respiration in the cell.
10. List three importance of anaerobic respiration.
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22. Appreciate Life
Embrace Education
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