Chapter 19: Bacteria and Viruses Notes
are a classification above kingdom
- Eubacteria: most of the bacteria are in this category
and have peptidoglycan (short chains of amino acid, peptides and carbs) in
the cell walls.
ancient bacteria that usually live in unusually harsh environments
such as hot springs, stomach acid and salty water. Archaebacteria have different Cell
Walls, cell membranes and ribosomal RNA than Eubacteria. They also do not have peptidoglycan in
the cell walls.
- Cell Walls: Gram staining separates Eubacteria into
Purple which are gram positive and have a thicker layer of peptidoglycan
in the cell wall than Gram negative which are Pink. Gram negative bacteria have an extra
layer of lipid on the cell wall that stops the purple stain from entering.
- Movement: Flagella
(tails), Spiral shaped bacteria move by corkscrew motion, myxobacteria
produce a layer or slime to glide in
- Autotrophs: either use the sun to photosynthesis
(photoautotroph) or they can oxidize inorganic compounds as food
- Heterotrophs: ferment sugars or feed on dead stuff
Growth and Reproduction
Binary fission is asexual reproduction where the
bacteria just divide into identical cells.
Conjugation: Bacteria make a gridge and exchange
Transformation: Bacteria incorporate DNA from dead
Transduction: use viruses to transfer DNA from bacteria
to other bacteria.
19-2 Bacteria in Nature
help the ecosystem recycle nutrients
down complex molecules (dead trees, corpses…) into simple molecules such
as water, nitrogen compounds and CO2
Can’t be used directly because of the triple bond
be “fixed” to ammonia
grows in nodules of in the roots of soybeans and other legumes. It is a Mutual relationship where the
plant provides nutrients for bacteria and the bacteria converts nitrogen
for the plant.
Bacteria and disease:
Pathogens (disease causing agent)
tissue or the infected area (ex. Tuberculosis bacteria break down lung
toxins that harm (Streptococcus: strept throat cause a rash or e-coli food
poisoning is caused by toxins released)
stimulate the immune system to fight bacterial infection.
and tetracycline block the growth and reproduction of bacteria.
Human Uses of Bacteria
- Make cheese,
yogurt, buttermilk, sourcream, pickles, sauerkraut and vinegar.
petroleum in spills
drugs (insulin, hemoglobin)
stable enzymes in bacteria from Yellowstone hot springs
frying, steaming, microwave
word for poison
are not living things because they are not able to reproduce independently
Protein coat (capsid, that surrounds a core of DNA or RNA)
Lytic cycle- virus enters the cell, make copies of itself
and causes the cell to burst.
Lysogenic cycle- a virus imbeds its DNA into the DNA or the host cell and
is replicated along with the host cell’s DNA.
Bacterial DNA called prophage.
Virus and Disease
Polio, AIDS, measles, mumps, yellow fever, colds flu
stimulates the immune system providing immunity to killed viruses or viral
proteins injected. The body makes
viruses; disrupt normal controls on cell growth causing cancer
Usually RNA is copied from DNA but in retroviruses DNA is copied from the
viral RNA. AIDs is a retrovirus
Cow and Scrapies are prion diseases.
There are no DNA or RNA, just proteins.
- TSE Transgenic
Spongiform encephalitis is the human form of Mad Cow. Proteins that come in contact with the
prion unwind. This makes holes in
the brain so the brain looks like a sponge.