UNIT 8 FUNCTIONS OF THE LIVING THINGS I. Título

Transcription

1 Título

2 1. CHARACTERISTIC OF THE LIVING THINGS. The living things have some especific characteristics: They are composed of biomolecules. They are formed by cells. They do three vital functions: Nutrition, Interaction and Reproduction.

3 2. THE CELL. CELLULAR THEORY: The cells are the basic unit of function and organisation in the living things. All the living things are composed by one or more cells. A single cell is the simplest form of a living thing. THE CELL LIKE UNIT OF ORGANISATION - Single cell living things: They are composed by a unique cell. - Multicellular living things: They are composed by two or more cells. Usually They have different types of cells which get together into groups called tissues to do a specific function.

4 2. THE CELL. TYPES OF CELLS Wa can differentiate two groups of cells: - Prokaryotic cells: They are more primitives and so they don t have nucleus. The genetic material is dispersed inside the citoplasm. This group is composed by bacterias. - Eukaryotic cells: They have a differentiate nucleus which have the genetic material inside. There are two types of eukaryotic cells: - Plant cells: They have an external and rigid wall sourrounding the plasma membrane, the cell wall, and they have specific organelles to do the photosyntesis, the chloroplasts. - Animal cells: They don t have cell wall and chloroplast neither.

5 2. THE CELL. TYPES OF CELLS Plant cell Animal cell

6 The function of nutrition has two objetives: To keep and to conservate the organism s estructures. To obtain the necessary energy to do the vital functions. We can differenciate two types of nutrition depending of how the living things get materials and energy: Autotrophic and Heterothophic nutrition.

7 AUTOTROPHIC NUTRITION. This type is done by plants, algae and some bacterias. It has four stages: - To take nutrients from the environment:the plants take water and mineral salts from the ground with their roots, and carbon dioxide from air with their leaves. Algae and bacteria take nutrients directly from the environment. - Production of Organic Material: This process is called photosyntesis, which is done in the cell s chloroplasts, where the chlorophylla take light from the Sun, and uses this energy to produce organic material (glucose) from water and mineral salts. As a result of this process oxygen is liberated.

8 AUTOTROPHIC NUTRITION. - Consuption of the organic material: The organic matrial produced in the photosyntesis is spread to every cell to produce new structures and to produce energy in a process called cell respiration. The cell respiration is produced in the mitochondrias where the glucose is burnt with oxygen. In this process is liberated energy and water which are useful for plants and also carbon dioxide which is expelled as a waste. Some bacterias can t do the cell respiration and they obtain energy from a process called fermentation.

9 AUTOTROPHIC NUTRITION. - Elimination of the waste products (excretion): During the process of nutrition some toxic products are produced and they must be eliminated.

10 AUTOTROPHIC NUTRITION. Importance of Photosyntesis: - The plants produce oxygen in the photosyntesis which can be used by other living things. - The plant purify the air because take carbon dioxide from it and release oxygen. - The plants can produce their own organic material (producers) and so the other living things need the plants to feed and get their nutrients (consumers). In this way, the organic material produced in the photosyntesis goes from ones living things to other, originating the food chain.

11 UNIT 8 LAS FUNCIONES DE LOS SERES VIVOS I HETEROTROPHIC NUTRITION: When living things can t produce organic material themself, they must eat other living things, this is heterotrophic nutrition. We diferenciate some stages in the heterotrophic nutrition: - Including organic material from the environment: The single cells living things can incorporate feed directly from the environment inside of vacuoles where these are digested.

12 UNIT 8 LAS FUNCIONES DE LOS SERES VIVOS I HETEROTROPHIC NUTRITION: The multicellular living things have a digestive system that transform the feed into simple molecules. - Exchange of gasses: The most of the animals have a respiratory system which gives oxygen to the digestive system and takes carbon dioxide from it to expel it outside of the body. This is external repiration. - Transport: The nutrients go from the digestive system to the circulatory system, which carry them to every cells in the body. - Metabolism: The nutrients are burnt with oxygen inside each cell to produce energy. In this process is also produced waste products (carbon dioxide and ammonia) which are expelled. The heterotrophic living things use the energy and the simple

13 UNIT 8 LAS FUNCIONES DE LOS SERES VIVOS I HETEROTROPHIC NUTRITION: molecules to make complex molecules, such as, proteins, fats and nucleic acids, and so renew the cellular structures. - Excretion: The excretory system eliminates the waste products originated in the cell respiration.