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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