Bacteria

I. Prokaryotes Prokaryotes: single-celled organisms that lack a nucleus 1. Eubacteria – common bacteria 2. Archaebacteria – lives in extreme harsh environments

Identifying Prokaryotes 1. Shapes a. Bacilli (rod shaped) b. Cocci (spherical/circle) c. Spirilla (spiral)

a. Gram-positive (w/peptidoglycan) – purple Gram Staining: Helps to determine what type of antibiotic to use To treat the bacterial infection 2. Cell Walls a. Gram-positive (w/peptidoglycan) – purple b. Gram-negative (w/o peptidoglycan – red Peptidoglycan is a sugar

Staphyl: Clumps or clusters b. Strepto: long chains c. Diplo: pairs 3. Arrangement Staphyl: Clumps or clusters b. Strepto: long chains c. Diplo: pairs

4. Movement Propelled by tail-like structure called flagella b. Glide along a slime secretion c. Move along like snakes d. Some don’t move

Obtaining Energy 1. Autotrophs a. Photoautotrophs: obtain energy from photosynthesis b. Chemoautotrophs: obtain energy from inorganic molecules

2. Heterotrophs a. Can cause food poisoning b. Photoheterotrophs: photosynthetic, but also need organic compounds for nutrition

Releasing Energy 1. Obligate aerobes: require oxygen 2. Obligate anaerobes: cannot live in presence of oxygen 3. Faciltative anaerobes: do not need oxygen, but can live in the presence of it

Growth and Reproduction 1. Binary fission: cell divides, asexual 2. Conjugation: transfer of genetic information from one cell to another, sexual 3. In unfavorable conditions, many bacteria can form endospores – can remain dormant for months or years

II. Bacteria in Nature Decomposers 1. Help recycle nutrients – break down dead organisms 2. Used in sewage treatment

Nitrogen Fixers 1. Nitrogen fixation: converting nitrogen into a form plants can use (EX: Rhizobium grow on roots of soybeans and other legumes – converts nitrogen to ammonia for the plant)

Bacteria and Disease 1. Pathogen: disease-causing agents 2. 2 ways bacteria cause disease a. Break down tissues for food b. Release toxins 3. Many can be treated with antibiotics

Human Uses of Bacteria 1. Food – cheese, yogurt, buttermilk, sour cream, pickles, sauerkraut 2. Industry – cleaning up oil spills, mining minerals, synthesizing drugs

3. Bacteria live in our digestive tract to help in digestion (called normal flora)

Controlling Bacteria 1. Sterilization: destroy bacteria by subjecting them to great heat or chemicals a. Boiling, frying, steaming can all kill bacteria b. Disinfectant chemical solutions can be used in homes and hospitals 2. Refrigeration – bacteria grow slowly at low temperatures

Antibiotics Fighting Bacteria Bacterial disease can be fought with soap, chemicals, and antibiotics. Antibiotic-Resistant Bacteria Mutations that confer resistance to antibiotics are strongly favored in bacterial populations being treated with an antibiotic. 14

Viruses

A virus is an infectious agent made up of nucleic acid (DNA or RNA) wrapped in a protein coat called a capsid. Viruses have no nucleus, no organelles, no cytoplasm or cell membrane—Non-cellular This is why it does NOT belong to any kingdom. vs

Virus Parts

Viruses with RNA that transcribe into DNA are called retroviruses. Viruses are parasites—an organism that depends entirely upon another living organism (a host) for its existence in such a way that it harms that organism. HIV Infected Cell (This is the reason why HIV is so incurable.) A flea is a parasite to a dog and is harmful to the dog.

Certain viruses can only attack certain cell types Certain viruses can only attack certain cell types. They are said to be specific. Example: The rabies virus only attacks brain or nervous cells. Surface Markers Virus Receptor Sites It’s like the pieces of a puzzle. The ends have to match up so only certain pieces fit. Cell

A virus recognizes cells it can infect by matching its surface marker with a receptor site on a cell. Virus Surface Markers Cell Receptor Sites

Viral Infection 1. Infect cells and replicates inside host cell 2. Bacteriophage: viruses that infect bacteria

3. 2 types of viral infections a. Lytic infection: virus enters cell, make copies of itself and causes the cell to burst b. Lysogenic infection: virus embeds its DNA into the DNA of host and is replicated with host cell’s DNA

Lytic Cycle

Lysogenic Cycle

Viruses and Disease 1. Many viruses can be prevented through the use of vaccines (polio, measles, influenza) Vaccines are parts of a virus that are injected into you so that your body can recognize the parts and build antibodies to fight against the virus – not a cure 2. Oncogenic viruses cause cancer 3. Prions contain no DNA or RNA, only protein

Importance: Beneficial: *Harmful Causes disease—pathogenic Disease producing agent—pathogen Human Diseases: Warts, common cold, Influenza (flu), Smallpox, Ebola, Herpes, AIDS, Chicken pox, Rabies Viruses disrupt the body’s normal equilibrium/balance Viruses can be prevented with vaccines, but NOT treated with antibiotics. (antibiotics treat bacteria) Beneficial: Genetic Engineering—harmless virus carries good genes into cells.

Virus Living Cell Cell membrane, cytoplasm, genetic material, organelles RNA or DNA core (center), protein coat (capsid) Structure Copies itself only inside host cell--REPLICATION Asexual or Sexual Reproduction DNA and RNA Genetic Material DNA or RNA Growth and Development NO YES—Multicellular Organisms Obtain and Use Energy NO YES Response to Environment YES NO Change over time NO YES