Chapter 7: Lesson 1 & Lesson 3 Bacteria & Viruses Chapter 7: Lesson 1 & Lesson 3

What are Bacteria? Lesson 1

Characteristics of Bacteria Microscopic Prokaryotic: No membrane bound organelles Can live in both living or dead organisms Bacteria outnumber your cells 10 to 1 in your own body! Archaea are similar to bacteria live in extreme environments (Very Warm or Cold , No Oxygen

Structure of Bacteria Cytoplasm DNA Cell Membrane and Cell Wall Ribosomes Protective Capsule Prevents white blood cells from surrounding bacterium

Sizes and Shapes of Bacteria Much smaller than plant or animal cells Bacteria = 1-5 micrometers Average Eukaryotic cell = 10- 100 micrometers

Obtaining Food and Energy Many bacteria feed on dead organisms, we call them decomposers! Parasites: can cause tooth decay, feeding on sugars Photosynthetic bacteria: Use light energy to make their own food, like plants. Chemosynthetic bacteria: Use energy from Chemical reactions.

Aerobic vs. Anaerobic Aerobic Bacteria Anaerobic Bacteria Need Oxygen to survive Most bacteria are Aerobic bacteria Do not need Oxygen to survive

Movement Flagella: Long whiplike structures used for movement Twisting and spiraling as they move Pili: Grappling hooks!

Reproduction Conjugation Binary Fission

Endospores Archaea

What are Viruses? Lesson 3

Characteristics of Viruses Strand of DNA or RNA surrounded by a layer of protein Can infect and replicate itself in a host cell No Cell Wall, Nucleus or any other organelles 20 to 100 times smaller than most bacteria

Dead or Alive? Scientists do not consider a virus to be alive Viruses: Are not organized Don’t respond to stimuli Don’t use energy Don’t grow Don’t reproduce on their own (need a host)

Viral Replication

Viral Mutations During replication, DNA or RNA frequently mutates. Mutations enable viruses to adjust to changes in host cells Host cells change over time to prevent viruses from attaching to the cell Mutations produce new ways to attach to host cells

Viral Diseases Chicken Pox Influenza Pneumonia Common Cold Rabies Latent Viruses: HIV Attacks White blood cells

Treating and Prevention Immunity: Unable to develop a disease Antibody: a protein that can attach to a pathogen and make it useless Antibodies bind to viruses and other pathogens to prevent attack

Vaccines Vaccine: A mixture containing material from one or more deactivated pathogens, such as viruses.