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In order to live, organisms use the function of nutrition to obtain the matter and energy they need.
They interact with their environment thanks to the function of interaction, and they continue to have descendants due to the function of reproduction.
4.1. Nutrition
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The purpose of nutrition is to ren
ew and help preserve the organism's structure as well as obtaining energy to perform the three vital functions.
Cellular metabolismis a combination of chemical reactions. This enables cells to obtain the necessary nutrients and energy to keep them alive.
In order to feed themselves, living things take substances from the environment which surrounds them, and cellular metabolism takes place in their cells.
Metabolism consists of two stages: anabolism and catabolism.
| Cell metabolism | |
Anabolism
| Catabolism
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11.37.01.png?idcurso=474459 "Vital functions (3)")
11.37.14.png?idcurso=474459 "Vital functions (4)")
During cell metabolism, in addition to matter and energy, waste substances are released from the organism.
4.1.1. Nutrition types
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There are two types of nutrition, depending on the type of matter obtained:
- Autotrophic nutrition: This type of nutrition is performed by organisms that obtain inorganic materials from the environment, which they transform into organic material. Plants, algae, and some bacteria perform autotrophic nutrition.
- Heterotrophic nutrition: This is performed by organisms that take organic matter from the environment. Examples of living things that use heterotrophic nutrition are: animals, fungi, protozoa and some bacteria.
4.2. Interaction
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Interaction allows living things to interact with their environment, detect any changes in it and react to them.
Stimuliare the changes in the environment that may provoke a response in a living thing. They are perceived by thereceptors, which are cells or structures specialised in perceiving stimuli.
Living things can respond to stimuli either with movements or by producing substances called hormones, which produce changes in how something functions or behaves.
4.3. Reproduction
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The purpose of reproduction is to create descendants and, in this way, continue the species.
There are two types of reproduction: asexual and sexual.
- Asexual reproduction: a single individual creates multiple descendants which are identical. It occurs in all unicellular organisms and in some multicellular ones. Unicellular living things only have one cell, so they can only reproduce by using the same cell.
There are three main types:
Key concepts
- In order to live, living things perform three vital functions: nutrition, interaction and reproduction.
- Asexual reproduction results in the production of many offspring which are identical to the parent.
- In sexual reproduction, two individuals are needed, and the offspring have characteristics from both parents.
- • Bipartition: the cell divides into two cells of similar size.
- • Budding: the cell also divides into two cells, but this time they are very different in size.
- • Sporulation: one single individual divides its nucleus, creating many new individuals.
- • Sexual reproduction: it requires two individuals of opposite sex. The number of descendants is smaller than in asexual reproduction and the offspring are not identical. Multicellular organisms perform this type of reproduction.
Some species are capable of performing both types of reproduction.
