UNIT 4 Living organisms. Plants.

1. There are two characteristics that all living beings have in common: they are made of cells and they do three vital functions.

2. All life on Earth depends on plants because they produce oxygen and food for other living beings.

3. Most plants are made up of a root, stem, leaves and vessels.

4. The roots fix the plant to the ground and allow water and minerals to enter in the plant.

5. The stem holds up the rest of the plant. It is thin, green and flexible.

6. The leaves are normally green, flat and have veins running through them.

7. The vessels are cells that run through the inside of the root, stem, branch and veins of the leaves and contain the water and other substances.

8. Plants have autotrophic nutrition so that they produce the nutrients that they need.

9. Plants do the photosynthesis when they use energy from the sunlight to make nutrients.

10 AND 11. The photosynthesis takes place inside the cells of the green parts of the plant, because they contain chlorophyll, which absorbs the sun´s energy.

12. Fortunately, photosynthesis produces oxygen as a waste gas.

13. Plants can react to changes in their environment. For example, most of plants produce flowers in spring and lose their leaves in autumn.

14. All plants can reproduce to produce descendants.

15. Plants have sexual and asexual reproduction.

16. Sexual reproduction in plants consists of four stages: pollination, fertilisation, seed and fruit formation and germination.

17. The pollination: a grain of pollen is transported to the pistil of another flower by the wind or by an insect.

18. Fertilisation: the grain of pollen joints together with the ovules inside the pistil.

19. Seed and fruit formation: the pistil is transformed into a fruit and the fertilised ovules are transformed into a seed and are dispersed.

20. Germination: seeds that reach the soil germinate and grow into a new plant

21. In asexual reproduction, one part of the plant develops into new smaller plants.