Bacteria, Viruses, and Diseases They Cause

Bacteria Monera kingdom was recently divided into Archaebacteria and Eubacteria. Shapes: Bacilli: rod-shaped Coccci: sphere-shaped Spirilla: spiral-shaped

Bacteria - Nutrition Chemoheterotrophs: must obtain food from organic molecules. Ex: E. coli eat on good and may release toxins. Photoheterotrophs: can obtain energy from sunlight, but still need organic molecules to feed on. Photoautotrophs: obtain all food from sunlight.

Bacteria – Living Conditions Obligate aerobes: require oxygen to live. Obligate anaerobes: require the absence of oxygen to live. Facultative anaerobe: can survive with or without oxygen.

Bacteria – Reproduction Binary fission: most use this form of simply splitting in half. Conjugation: a hollow bridge forms between 2 bacterial cells and they transfer genetic material. Spore formation: occurs when conditions are unfavorable and preserves DNA.

Bacteria - Uses Some are decomposers. Some are nitrogen-fixers. Help ecosystem recycle nutrients. Some are nitrogen-fixers. Convert nitrogen gas into a usable form. Some used in human health. Found in foods, drinks, and our digestive system to help break down food.

Viruses Particles of nucleic acid, protein, and sometimes lipids. Usually composed of DNA or RNA core surrounded by a protein coat, called a capsid. They are NOT ALIVE!

Viruses - Bacteriaphage Attack bacteria.

Viruses – Type of Invasion They are parasites because they must infect a living cell to grow and reproduce Some viruses replicate themselves immediately, killing the host. Others do not kill the host immediately. Lytic Infection: virus enters the cell, copies itself, and causes the cell to burst Lysogenic Infection: virus integrates its DNA into DNA of host cell, so it is replicated.

Viruses - Retrovirus Contain RNA as their genetic information Ex: AIDS

Bacterial Diseases Produce disease in one of two ways. Prevention Some damage cells and tissues of infected organisms by breaking down the cell for food. Others release toxins that travel through the body of the host. Prevention Vaccine: preparation of weakened or killed pathogen. Antibiotics: compounds that block growth of bacteria. Controlling Bacteria Sterilization, disinfection, and food processing.

Viral Diseases Produce diseases by disrupting equilibrium. Viroids: often infect plants. Prions: contain no RNA, just protein. Cannot be cured!