chapter 19 bacteria & viruses. i. bacteria are ________________________-lack a nucleus and have...

Chapter 19

Bacteria & Viruses

I. Bacteria

• Are ________________________-lack a nucleus and have few organelles

• Much smaller than eukaryotes• Eubacteria-larger kingdom than

archaebacteria;usually have protective cell wall and determines shape

Prokaryotes

• __________________________-not such a strong,if any,cell wall,DNA sequences more like eukaryotes;live in HARSH environments like hot springs or volcanic vents

Archaebacteria

Identifying bacteria:

– by shape• 1) rod-shaped are __________________• 2) spiral-shaped

are_______________________• 3) spherical-shaped are cocci(coccus-

singular)

Bacillus or bacilli

Spirillus or spirilla

• by cell walls-use Gram Staining-Gram(+) have thick_______________________walls/gram(-) have thinner walls

• by movement-some do not move and some have flagella

peptidoglycan

B. Metabolic Diversity

• Heterotrophs– _____________________-must take in organic molecules

for energy and supply of Carbon-as do we– _____________-

• Autotrophs– ____________________-– ______________-as those found in volcanic vents

Chemoheterotrophs

photoheterotrophs

photoautotrophs chemoautotrophs

Releasing Energy

– 1) Obligate aerobes-need constant supply of O2– 2) _______________________-do not need O2– 3) Faculatative anerobes-can survive w/or w/o

O2-example-E.coli

Obligate anaerobes

C. Growth and Reproduction

• _________________________grows,replicates DNA

and splits in half

Binary fission

• ________________________-exchange genetic info w/ a “bridge”

conjugation

• Some produce_________________________, which can lie dormant and germinate

spores

D. Importance of Bacteria

• Decomposers

• N-fixers-for plants

• Human uses-food production ;cleaning up oil spills

• Assist digestion

II. Viruses-particles of nucleic acids,protein and sometimes lipids

• Not living-reproduce only by infecting living cells• Usually has a DNA or RNA core w/outer protein coat• Outer protein coat called a ______________-which

enable it to enter a host cell—often destroying host cell

• ________________________-viruses that infect bacteria

capsid

bacteriophage

• ____________________infection-virus enters cell,makes copies ,and causes cell to burst

• _____________________________-virus integrates DNA into DNA of host cell,and viral genetic info replicates along w/host

Lytic

Lysogenic

• _______________________________-contain RNA as genetic info and produce DNA copy of RNA

retroviruses

III. Diseases

• Bacterial– Infect by damaging cells or releasing toxins– Mycobacterium tuberculosis– Streptococcus– Cornyebacterium diptherae– Anthrax– Lyme’s disease– Tetanus– Meningitis– Tooth decay

• prevention – -_______________________preparation of weakened

or killed pathogens– ________________________-compounds that block

the reproduction or growth of bacteria

vaccination

antibiotic

• 2)control-sterilization,heat,disinfectantants,proper food processing and storage

B. Viral

• Common cold• Influenza• Smallpox• Warts• AIDS• Chickenpox• Measles• Hepatitis A,B, or C• West Nile• Polio

– ________________________________single-stranded RNA moleculesw/no capsid-attack plants

– ______________________-virus –like particles of protein-may cause protein clumps that induce new prions---example-Mad Cow Disease

viroids

prions