Chapter 19 Bacteria and Viruses. 19-1 I.Bacteria- “Monerans”- no longer a formal kingdom, but still refers to ALL prokaryotes A. Prokaryotic Cells  unicellular.

Chapter 19 Bacteria and Viruses

19-1 I.Bacteria- “Monerans”- no longer a formal kingdom, but still refers to ALL prokaryotes A. Prokaryotic Cells  unicellular with no nucleus or membrane-bound organelles i. Now two Prokaryotic Kingdoms 1. Eubacteria and Archaebacteria B. Used to be in one formal kingdom  Monera C. Eubacteria i. Cell walls contain peptidoglycan (carbohydrate) iii. Live everywhere, fresh water, salt water, on/in humans;.01% can cause disease ii. May contain a second membrane

E. coli, a Typical Eubacterium Peptidoglycan Cell Membrane Ribosomes Pili DNA Flagellum Cell Wall

D. Archaebacteria i. Cell walls lack peptidoglycan ii. Live in extreme or harsh environments often with no O 2 available 1. Halophiles = live in high concentrations of salt 2. Methanogens = live in marshes, lake sediments, digestive tract of animals 3. Thermoacidophiles = low pH, high temperature 4. None cause disease

E. Identification: i. Shape 1. Bacilli = rod shaped Bacilli 2. Cocci = sphere shaped Cocci 3. Spirilla = spiral shaped Spirilla Page 473

ii. Cell walls of Eubacteria- THICK OR THIN? 1. Gram Staining = used to tell the difference btw. the two types of Eubacteria for effective antibiotic; i.e. gram-positive antibiotic won’t kill gram-negative bacteria a. Gram Positive  stains purple = cell wall contain thick peptidoglycan b. Gram Negative  stains pink = have thinner cell walls inside a lipid layer iii. Movement 1. Whether they move & how they move a. flagella, spiral forward, snake, or glide in slime

i. Heterotrophs F. Metabolic Diversity-Modes of Nutrition 1. Photoheterotrophs – use sunlight for energy but need organic compounds for Carbon 2. Chemoheterotrophs – use organic compounds for energy and carbon ii. Autotrophs 1. Photoautotrophs – use sunlight to make food 2. Chemoautotrophs – use inorganic compounds to make food  ex live in hydrothermal vents deep in ocean

G. Releasing Energy i. Obligate Aerobe =Require constant supply of O 2 1. Ex. Mycobacterium tuberculosis ii. Obligate Anaerobe = Doesn’t require O 2 and may be killed by it 1. Ex. Clostridium botulinum  can grow in soil and can grow in canned food that has not been properly sterilized iii. Facultative Anaerobe = Doesn’t need O 2 and is not killed by it 1. Ex. E. coli  Lives w/o O 2 in intestines and w/ O 2 in sewage/contaminated H 2 O

H. Growth and Reproduction i. Binary Fission 1. Replicates DNA and divides in half Binary Fission ii. Conjugation 1. Exchange genetic info. across a “bridge” Conjugation iii. Spore Formation (endospores) 1. Conditions become unfavorable  form endospores  can remain dormant for years Spore Formation

Streptococcus pneumoniae – Bacteria Causes: Ear infections Meningitis Pneumonia

II. Importance of Bacteria A. Maintaining the living world-ECOLOGICAL IMPORTANCE i. Producers-cyanobacteria, green sulfur bacteria, purple bacteria; methanogens, halophiles ii. Decomposers  break down nutrients in dead matter and the atmosphere iii. Nitrogen Fixers  convert Nitrogen gas into ammonia for plants to use; iv. Human Uses 1. Production of food/beverages, clean oil spills, remove waste products and poisons from water, live in intestines

19-3 III. Diseases and Bacteria A. Bacterial toxins can travel throughout the body i. Streptococcus can release toxins into bloodstream and cause scarlet fever B. Preventing Bacterial Disease i. Vaccine = Preventative (Before exposure): weakened or killed pathogen injected into the body causing the body to produce immunity to the disease and destroy any new pathogen

ii. Antibiotics = Upon exposure; They block the growth and / or reproduction of bacteria C. Controlling Bacteria i. Sterilization = destroys bacteria by subjecting them to great heat ii. Disinfectants = chemical solutions that kill pathogenic bacteria iii. Food Storage = Refrigerate  bacteria will take longer to multiply; colder temps slows bacterial growth

Bacterial Diseases Page 488 Pathogenic-means disease-causing; PATHOGENS

IV. Viruses 19-2 A. Nonliving particles B. Made of only 2 parts: i. Capsid = outer protein coat ii. Nucleic Acid – DNA or RNA in inner core C. Reproduce by infecting hosts, very specific D. Named after the disease they cause or organ they infect, Adenovirus  found in adenoid tissue i. Use numbers if virus affects the same host, T1 – T7; infect E.coli found in the intestines

E. Structure (page 479) i. “Lunar Lander”-bacteriophages ii. Helical iii. Enveloped- Spherical with projections; typical of animal viruses iv. Polyhedral- means “many faces” -geometric

What Is a Virus? Head Tail sheath DNA T4 Bacteriophage Tobacco Mosaic Virus Influenza Virus RNA Membrane envelope Tail fiber RNA Capsid proteins Capsid Surface proteins Page 479

capsid nucleic acid lipid envelope surface proteins capsid nucleic acid lipid envelope Surface proteins capsid surface proteins nucleic acid helical (rabies) polyhedral (foot-and-mouth disease) enveloped (influenza)

Bacteriophages infect bacteria. capsid DNA tail sheath tail fiber

Viruses enter cells in various ways. colored SEM; magnifications: large photo 25,000; inset 38,000x –bacteriophages pierce host cells

F. Viral Infection i. Lytic Infection- Immediate take-over 1. Enters cell, makes copies of itself, causes cell to lyse (burst)

ii. Lysogenic Infection- aka Latent viruses 1. Virus embeds DNA into cell’s DNA (prophage) 2. Viral DNA replicates with host DNA 3. Virus does not immediately take over 4. Can carry on for many years and then go into the Lytic Cycle

Viral Infection Bacteriophage injects DNA into bacterium Bacteriophage DNA forms a circle Lytic Infection Lysogenic Infection Page 481

G. Retrovirus i. Contain RNA as genetic info. 1. RNA is used to make DNA instead of RNA being copied from DNA (retro = backwards) ii. Ex. HIV 2. DNA is inserted into the DNA of the host cell

V. Viruses in Humans A. produce disease by disrupting the body's normal equilibrium B. attack and destroy certain cells in the body, causing symptoms of the disease C. Others cause infected cells to change patterns of growth and development D. cannot be treated with antibiotics E. Symptoms may be treated with over-the-counter medicines F. vaccines work only if used before an infection begins

Viral Diseases Page 488

G. Viroids and Prions i. Viroids cause disease in plants. ii. Prions cause disease in animals. 1. single-stranded RNA molecules that have no surrounding capsids 1. contain only protein—no DNA or RNA 3. Ex. Mad cow disease-in humans-called Variant Creutzfeldt-Jakob disease (vCJD) 2. nerve cells become damaged

19–1 Which characteristic distinguishes eubacteria from archaebacteria? A. Eubacteria lack peptidoglycan in their cell walls. B. Eubacteria contain peptidoglycan in their cell walls. C. Eubacteria lack a nucleus. D. Eubacteria do not possess mitochondria.

19–1 Rod-shaped prokaryotes are called A. bacilli. B. cocci. C. spirilla. D. streptococci.

19–1 Bacteria that must live without oxygen are called A. obligate aerobes. B. facultative anaerobes. C. obligate anaerobes. D. facultative aerobes.

19–1 Prokaryotes that make their own food molecules from carbon dioxide and water but live where there is no light are called A. photoautotrophs. B. photoheterotrophs. C. chemoautotrophs. D. chemoheterotrophs.

19–1 Bacteria that attack and digest the tissue of dead organisms are called A. decomposers. B. nitrogen fixers. C. chemoautotrophs. D. archaebacteria.

19–2 Viruses that contain RNA as their genetic information are known as A. prions. B. oncoviruses. C. retroviruses. D. bacteriophage.

19–2 The first type of virus to be studied was the A. bacteriophage. B. tobacco mosaic virus. C. influenza virus. D. AIDS virus.

19–2 Which of the following statements about viruses is true? A. Viruses appear similar to bacteria when studied with a light microscope. B. Viruses display the essential characteristics of living things. C. Viruses can reproduce independently if they contain DNA. D. Viruses cannot reproduce unless they infect a living cell.

19–2 A virus integrates its DNA into the DNA of the host cell but remains inactive for a while in A. a lytic infection. B. a lysogenic infection. C. neither a lytic nor a lysogenic infection. D. retroviral infection.

19–2 Retroviruses are considered unique because A. they have RNA in their capsid and not DNA. B. they have DNA in their capsid and not RNA. C. after infection of a host cell, their RNA makes DNA. D. after infection of a host cell, their DNA makes RNA.

19–3 Biologists know that bacteria can cause human disease by A. entering cells and using the cell to make new bacteria. B. producing toxic substances that interfere with normal cell function. C. decomposing the remains of dead organisms. D. changing atmospheric nitrogen into nitrogen compounds.

19–3 A process that destroys bacteria by subjecting them to great heat is known as A. refrigeration. B. sterilization. C. pickling. D. boiling.

19–3 Which of the following diseases is transmitted by a mosquito bite? A. influenza B. measles C. West Nile virus D. chickenpox

19–3 Which of the following diseases is thought to be caused by prions? A. diphtheria B. mad cow disease C. tuberculosis D. smallpox

19–3 The best way to combat viral diseases is A. to use antibiotics. B. to treat individual symptoms. C. to use preventive vaccines. D. to let the disease “cure itself.”