UNIDAD 2 DEL LIBRO DE SANTILLANA CON NOMRRE ESSENTIAL NATURAL SCIENCE 2 º ESO Y ISBN 978 84 294 7978 2 ES UN BREVE RESUMEN

1. UNIT
The nutrition function
2
THE NUTRITION
PROCESS
Natural Science 2. Secondary Education

2. UNIT
The nutrition process
2
NUTRITION
OBTAINING SUBSTANCE
NUTRIENTS RESPIRATION DISTRIBUTION EXCRETION
AUTOTROPHIC HETEROTROPHIC
NUTRITION NUTRITION
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Natural Science 2. Secondary Education

3. UNIT
The nutrition process
2
Obtaining nutrients
• Nutrients are the substances (organic or inorganic)
that living things ingest and that can be used by their
cells.
• There are two types of nutrition:
• Autotrophic • Heterotrophic
Inorganic
substances
Energy Food
Organic Organic
nutrients nutrients
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Natural Science 2. Secondary Education

4. UNIT
The nutrition process
2
Autotrophic nutrition
• Autotrophic organisms produce organic nutrients
from inorganic substances, such as:
• Water
• Mineral salts
• Carbon dioxide
Natural Science 2. Secondary Education

5. UNIT
The nutrition process
2
Autotrophic nutrition
• One example is photosynthesis. Plants and algae
make organic nutrients using the energy from
sunlight.
ENERGY
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Natural Science 2. Secondary Education

6. UNIT
The nutrition process
2
Heterotrophic nutrition
• Heterotrophic organisms cannot make organic
matter from inorganic matter. Therefore, they obtain
nutrients from other organisms or their derivatives.
• Animals are an example of heterotrophic
organisms.
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Natural Science 2. Secondary Education

7. UNIT
The nutrition process
2
Respiration
• Respiration is the process where a living organism takes
in oxygen and expels carbon dioxide.
• This process also takes place in cells, which use oxygen
to generate energy from nutrients. Mitochondria are the
organelles that carry out cellular respiration.
Carbon
dioxide
Oxygen
Natural Science 2. Secondary Education

8. UNIT
The nutrition process
2
Cellular respiration
• In this process, the mitochondrion takes in
oxygen, obtains energy from nutrients and expels
carbon dioxide and water.
Oxygen Carbon
dioxide
Energy
Water
Carbohydrates
Respiration in a
mitochondrion
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Natural Science 2. Secondary Education

9. UNIT
The nutrition process
2
Substance distribution in unicellular organisms
• In unicellular organisms, the cell exchanges
substances directly with the environment through
the membrane.
The exchange of
substances in a
protozoan
Nutrients
Waste
Natural Science 2. Secondary Education

10. UNIT
The nutrition process
2
Substance distribution in multicellular organisms
• In multicellular organisms, different parts of the
body specialise in:
• Taking in or expelling substances.
• Transporting substances.
The circulatory
The digestive system
system of a fish
of a bird
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Natural Science 2. Secondary Education

11. UNIT
The nutrition process
2
Excretion
• This is the process by where living beings expel
the waste products generated by their activity.
The excretory system
of a reptile
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Natural Science 2. Secondary Education