Cells & Bacteria Wrap Up!

1. Cells & Bacteria Wrap Up!

2. Today’s Lesson • We will have most of the major information needed for the test in a little over 2 weeks. • Our main topics are: • Difference between animal and plant cells • Basic Reproduction of Cells • Solutions • Diffusion • Turgidity • Communities & Addresses • Simple Food Webs • Pathogens (Bacteria, Fungi & Viruses)

3. Animal Cells • Animal cells are different than plant cells. They have a cell membrane, cytoplasm, mitochondrion and a nucleus. • The shape of an animal cell varies. • The nucleus is in the middle of the cell

4. Plant Cells • Plant cells have cell walls, chloroplasts, nucleus, cytoplasm, vacuole, cytoplasmic membrane (cyctoplasm) and a mitochondrion. • Plants have tough cell walls made out of cellulose. • They can have a large hole in the middle filled with sap.

5. Solutions • A solution is made up of two parts, the solute and the solvent. • The solute (can be solid) dissolves in the solvent. • A concentrated solution has a lot of solute dissolved in the solvent. • A dilute solution has a small amount of solute dissolved in the solvent.

6. Diffusion • Diffusion is the movement of particles from a high concentration to a lower concentration until they spread out evenly (). • Osmosis is the passage of water molecules from a dilute solution into a more concentrated solution through a partially permeable membrane (some liquid can get through).

7. Turgidity • When a cell increases the amount of water, it is said to be turgid. • When water is lost from the cell, it is said to have wilted (plant) or flaccid (animal).

8. Communities & Addresses • Animals live in different areas. It can be described depending on different areas: • Biosphere (planet) • Biogeographic Region (continent) • Biome (part of continent) • Habitat (suburb or local area) • Microhabitat (direct area where the living organism lives)

9. Simple Food Web • A food web shows which animals eat each other. • Remember that there needs to be less animals the further up the food chain you go.

10. Pathogens • Bacteria (細菌), viruses (病毒) and fungi (真菌) are all microbes (微生物). The microbes that cause disease are called pathogens (病原體) • Not all bacteria, viruses and fungi cause disease. Some diseases are also not caused by microbes.

11. Bacteria • Bacteria are cells large enough to be seen under a microscope. • Bacteria has a cell wall, but no proper nucleus (核). They just have a loop of DNA. • Some bacteria are helpful (medication), but some cause diseases.

12. Bacteria #2 • Bacteria go through 4 different phases of growth. They are lag, exponential, stationary and death. • They tend to grow together as a colony.

13. Fungi • Fungi cause disease such as ringworm (癬) and athletes foot (運動員的腳) • They release enzymes (酶) that digest the food outside the fungus. For athletes foot, they eat skin. • Fungi reproduce by making spores (孢子)

14. Viruses • Viruses are parasites (寄生蟲), which means they need a host for food and to be able to reproduce. • Viruses can only exist (be found) inside living cells. • Viruses reproduce very quickly and do not respond to antibiotics (抗生素).