Cells & BacteriaWrap Up!

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)

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

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.

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.

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).

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).

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)

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.

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.

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.

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.

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 )

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 ).