What is a plant?

1. What is a plant? • Nearly all plants are autotrophs, meaning they make their own food. • They are also called producers. • All plants are eukaryotes. • All plants are multicellular. • All plant cells are surrounded by a cell wall. • All plant cells contain green chloroplasts, which contain chlorophyll. • Chlorophyll changes carbon dioxide, water and the energy in sunlight into food (glucose, a sugar) for the plant to use. • This process is known as photosynthesis.

2. Obtaining Water and Other Nutrients • Vascular Plants have tissues, or groups of cells, that are specialized to obtain water and other nutrients. • Phloem (Flow-um) is the vascular tissue that carries food (sugar) throughout large plants. • Xylem (zy-lum) is the vascular tissue that carries water and other nutrients throughout large plants.

3. Obtaining Water and Other Nutrients • Nonvascular Plants are so small that water and other nutrients can move from one cell to the next through the processes of diffusion and osmosis. • They do not have vascular tissues. • Non-vascular plants can get water from the environment or nearby cells.

4. Roots • Anchor seed plants to the ground • Absorb water and minerals from the soil • Sometimes store food in the form of starch

5. Stems • Carry substances between the roots and leaves • Support the plant • Hold the leaves up to the sun

6. Leaves • Capture the sun’s energy and carry out photosynthesis • Leaves have tiny holes called stomata which allow water to evaporate from the leaves. • This process is known as transpiration.

7. Reproduction • All plants undergo sexual reproduction that involves fertilization, the joining of a sperm cell with an egg cell. • Some plants require water to be present in order for the sperm to fertilize the egg. • Some plants reproduce by releasing spores. • Other plants reproduce by producing seeds that enclose the zygote.

8. Tropisms • Plants respond to environmental stimuli through tropisms. • A tropism is a plant’s growth response toward or away from a stimulus • Touch, light, and gravity are three important stimuli to which plants show growth responses, or tropisms. • Thigmotropism- response to touch • Phototropism- response to light • Gravitropism – response to gravity

9. Photosynthesis • Photosynthesis is the process where plants take the energy from sunlight and change it into food (glucose) • Water and carbon dioxide are required for photosynthesis to take place. • Photosynthesis produces glucose and oxygen. Photosynthesis.asf

10. Reproduction • Angiosperms are flowering plants. • They have specialized reproductive organs called flowers. • Flower buds are protected by a leaf-like sepal. • Petals are usually colorful in order to attract pollinators, such as insects.

11. Reproduction • Inside the flower are the male stamen and the female pistil. • The stamen is made of a stalk-like filament that holds up the anther, which produces pollen (contains the sperm) • The pistil has a sticky stigma that is held up by the style. The style connects the stigma to the ovary, which contains the eggs.

12. Reproduction • Once the eggs are fertilized, they become seeds and the ovary turns into a fruit. • Seed plants go through a variety of developmental stages beginning with the germination of the seed. Germination requires water. • The seed contains the young plant and stored food

13. Gymnosperms • These are non-flowering vascular plants that produce naked seeds, seeds not enclosed by a fruit. • Many have needle-like leaves. • They reproduce using structures called cones.

14. Exit Slips • Take out a sheet of paper, write your name on it, and answer the following questions. • What does multicellular mean? • How do non-vascular plants get water? • What tissue do vascular plants use to transport food? • In what part of the plant does most transpiration occur? • After fertilization takes place in a flower, what does the ovary become?