Viruses and Bacteria Viruses A virus is a

Viruses and Bacteria

Viruses • A virus is a piece of hereditary material (RNA or DNA) that is covered by protein that infects and reproduces in living cells. • Viruses are not considered living things because they are unable to reproduce on their own: they require a host cell. • Viruses are extremely small, much smaller than bacteria cells. • Active Viruses: The virus enters a host cell and become active right away by causing the cell to make new virus particles.

LABEL ACTIVE VIRUSES: A: Viruses attach to cell. B: DNA/RNA injected into cell C: Virus takes control of cell & makes new virus particles. D: Cell bursts open releasing 100’s of viruses to infect more cells.

• Latent Viruses: The virus enters the host cell and becomes a part of the cell’s DNA without destroying the cell or making new virus particles. The virus can hide for years before it becomes active. • Viral Diseases: Viruses can cause STDs. There are no antibiotic medications to cure viral diseases. Viral diseases can be prevented by vaccines. • Parts of a virus are: DNA/RNA & protein

LABEL LATENT VIRUSES A: Attach B: Virus becomes part of cell’s DNA. C: Cell divides. D: Virus becomes active. E: New viruses are made. F: Cell breaks open releasing new viruses.

BACTERIA • All bacteria belong to the Kingdom monera. • Bacteria are one-celled organisms that do not have a nucleus. • Bacteria reproduce by a process called fission - when a parent cell splits to produce two new cells that are exactly alike. • Some bacteria can also reproduce sexually by lining up beside each other and exchanging DNA. This process produces a cell that is different than the parent cells.

• Bacteria are everywhere- in the food you eat, in the air you breathe, and millions live in your body. • Most bacteria are beneficial to us: however, some can cause disease. • Many bacteria can cause STDs. • An organism, such as bacteria, that can cause disease is called a pathogen.

• Diseases caused by bacteria are usually treated with antibiotics. • An antibiotic is a substance produced by one organism that inhibits or kills another organism. • For example, penicillin prevents bacteria cells from forming cell walls so they cannot survive. • Some diseases can be prevented by vaccines.

• A vaccine is made from damaged or killed bacteria. • Vaccines are injected into the body so that the white blood cells can recognize the bacteria. • If they ever come in contact with the bacteria again, they can immediately attack and kill them. • Parts of a Bacteria: cytoplasm, cell membrane, cell wall & Flagella, capsule, DNA

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