BACTERIA & VIRUSES

BACTERIA

PROKARYOTIC in 2 of 3

Domains1. Eubacteria2. Archaebacteria

EUBACTERIAARCHAEBACTERIA

LARGERMORE VARIETIESCELL WALL

CONTAINS PEPTIDOGLYCAN

SOME HAVE DOUBLE CELL MEMBRANE

NO PEPTIDOGLYCAN

MEMBRANE LIPIDS DIFFERENT

SOME DNA SEQUENCES MORE SIMILAR TO EUKARYOTIC CELLS THAN TO EUBACTERIA

Identification

SHAPE

CELL WALL COMPOSITION

MOTILITY

METHOD OF OBTAINING ENERGY

PROKARYOTES

EUBACTERIA

CYANOTROPHIC

HETEROTROPHIC

ARCHAEBACTERIA

HELIOTROPHS

THERMOTROPHS

METHANOGENS

SHAPES

1. BACILLI

1. RODS

2. COCCI

1. BALLS

3. SPIRILLA

1. CORK-SCREW

Anaerobes Aerobes

I. ObligateI. Cannot tolerate

oxygenII. Faculative

I. +/- oxygen

Obligate Oxygen required

Oxygen Tolerance

Binary Fission

asexual reproduction

trigger: growth reaches 2x

http://www.classzone.com/books/hs/ca/sc/bio_07/animated_biology/bio_ch05_0149_ab_fission.html

Growth & Reproduction

Conjugation

Exchange of DNA thru hollow bridge that forms between 2 bacteria

Increases genetic diversity

http://highered.mcgraw-hill.com/sites/dl/free/0072835125/126997/animation6.html

Growth & Reproduction

Endospore Formation

Used when environmental conditions unfavorable

Dormancy can last years

Growth & Reproduction

Importance of Bacteria

1. DECOMPOSERS2. NITROGEN FIXERS3. INDUSTRIAL USES4. SYMBIOSIS in HUMANS

TRANSFORMATION of BACTERIA

During transformation a cell takes in DNA from outside the cell becoming a permanent component of the cell’s genome.

PLASMIDS

SMALL CIRCULAR PIECE OF DNA

NATURALLY FOUND IN SOME BACTERIA

CONTAINS DNA THAT PROMOTES REPLICATION

HAS GENETIC MARKER

PLANTS ANIMALS

CAN REMOVE CELL WALL & CELL MAY SPONTANEOUSLY TAKE UP FOREIGN DNA

OR INJECT PLASMIDS INTO CYTOPLASM

GENES CAN BE REPLACED

EUKARYOTIC CELL TRANSFORMATION

Pathogens

disease-causing agents

Bacterial Infections

Louis Pasteur 1st to prove bacteria can cause disease

bacteria produce illness in 1 of 2 ways:1. directly damage host cells or tissues2. release toxins (poisons) that then circulate

throughout body interrupting homeostasis

Preventing Bacterial Disease

vaccines: preparation of killed or weakened pathogens that prompts the immune system of the organism to produce immunity to the disease should they ever come in contact with it

Treating Bacterial Infections

antibiotics: compounds that block reproduction of bacteria or kill them

availability of antibiotics (since ~WWII) has been 1 of major reasons life expectancy increased dramatically during the 20th century

Controlling Bacterial Growth

heat sterilization: destroys bacteria by heating equipment used on patients to ~ 125 ◦C using either moist heat or dry heat

disinfectants: chemical solutions that kill bacteria, overuse in homes (antibacterial soaps) increase chance of resistance

food processing: food stored @ lower temperatures stays fresher longer because it decreases the bacterial reproductive rate; cooking food before consumption also kills bacteria

VIRUSES

NON-LIVING MADE OF A PROTEIN COAT (CAPSID) SURROUNDING NUCLEIC ACID

Bacteriophage Tobacco Mosaic Virus

Influenza Virus Rhinovirus

Lytic LysogenicCell infected with 1

virusTakes over host cell

metabolismMake many copies of

nucleic acid & capsids assemble

Cell bursts (lysis) releasing many copies of virus

Cell infected with 1 virus

Its DNA inserts into bacteria’s loop of DNA

Replicates as that cell goes through cell division

2 Types Viral Infection

LYTIC CYCLE

LYSOGENIC CYCLE

Animations

http://www.bio-alive.com/animations/virology.htm

Viral Disease in Humans

viruses make you sick by disrupting homeostasis in tissues and cells of your body

viruses cannot be treated with antibioticsbest protection is prevention

Vaccines : measles, mumps, chicken pox, influenza, HPV

treatment: once sick symptoms treated often with OTC products, some anti-viral meds available

Viral Diseases in Animals

viruses produce serious animal diseaseexamples: hoof-and-mouth (or foot-and-

mouth), BPV, swine flu, bird flu

Viral Disease in Plants

threat to agricultural plantsbecause plant cells surrounded by a cell wall

the plant viruses have a more difficult time infecting cells

many plant viruses have adaptations that allow them to enter damaged cells (small tear in a leaf means some cells damaged)

VIRUSES / CELLS

COPY FIGURE 19-11 FROM PAGE 483 OF BOOK ONTO PAGE 113 of notebook

Draw a virus and a bacteria of your choice, label their parts and write a 2 paragraph reflection on what you have learned about bacteria & viruses.