Daily Questions 1. What is the difference between binary fission and conjugation? 2. What are obligate anaerobes? 3. Archaebacteria belong to the domain _________________.

Daily Questions 1. What is a virus? 2. Name the three ways bacteria can reproduce. 3. Most bacteria are (heterotrophs/autotrophs).

Daily Questions 1.What is a phylum? 2.List Linnaeus’ 7 taxons in order from largest to smallest. 3. Name the three domains.

Daily Questions 1. What are the 4 ways bacteria can move? 2. What are chemoautotrophs? 3. What are photoheterotrophs?

Daily Questions 1. What is the difference between Archaebacteria and Eubacteria? 2. Your doctor says you have pneumonococcus. What shape of bacteria is this? 3. Your doctor says you have a “staph” infection. What do you know about this bacteria?

Chapter 19 Bacteria and Viruses

I. Prokaryotes A.Prokaryotes: single-celled organisms that lack a nucleus 1. Eubacteria – walls contain peptidoglycan (a carbohydrate) 2. Archaebacteria – lack peptidoglycan, DNA similar to eukaryotes, have different cell membrane lipids

Prokaryotic Body Plan bacterial flagellum pilus capsule cell wall plasma membrane ribosomes in cytoplasm

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

2. Cell Walls a. Gram-positive (w/peptidoglycan) – purple b. Gram-negative (w/o peptidoglycan – red

3. Arrangement a.Staphyl: Clumps or clusters b. Strepto: long chains

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

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

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

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

E.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 (such as anthrax)

Prokaryotic Fission The bacterial chromosome is attached to the plasma membrane before DNA replication Replication starts and proceeds in two direction from some point in the bacterial chromosome The DNA copy is attached at a membrane site near the attachment site of the parent DNA molecule The two DNA molecules are moved apart by membrane growth between the two attachment sites New membrane and new wall material are added transversely, through the cell’s midsection The ongoing, orderly deposition of membrane and wall material at the midsection cuts the cell in two

Conjugation nicked plasmid in donor cell conjugation tube to recipient cell Conjugation tube forms between a donor and recipient. An enzyme nicks the plasmid Plasmid DNA replication starts. The free DNA strand starts moving through tube In the recipient cell, replication starts on the transferred DNA The cells move apart and the plasmid in each forms a circle

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

B.Nitrogen Fixers 1. Nitrogen fixation: converting nitrogen into a form plants can use 2. Rhizobium grow on roots of soybeans and other legumes – converts nitrogen to ammonia for the plant

C.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 prevented with vaccines, can be treated with antibiotics

D.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)

E.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

III. Viruses A.Viruses: particles of nucleic acid and protein 1. Nucleic acid = DNA or RNA that contains instructions for making new copies of the virus 2. Capsid: outer protein coat

DNA and RNA DNA – deoxyribonucleic acid chemical compound (a nucleic acid, which contains hydrogen, oxygen, nitrogen, carbon, and phosphorus) with instructions for coding proteins that determines your genetic makeup RNA – ribonucleic acid nucleic acid that contains the sugar ribose

B.Viral Infection 1. Infect cells and replicate 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 DNA of host and is replicated with host cell’s DNA

C.Viruses and Disease 1. Many viruses can be prevented through the use of vaccines (polio, measles, influenza) measles, influenza) 2. Oncogenic viruses cause cancer 3. Retroviruses contain RNA 4. Prions contain no DNA or RNA, only protein

The Prophage Prophage = viral DNA that is inserted into a cell The prophage can have the cell make copies of the virus right away or may wait several generations (a latent infection) and then begins making copies at a later time