Transcript Viruses

Unit 8: Classification
and Kingdoms
Viruses, Kingdom
Archaebacteria, &
Kingdom Eubacteria
Can cold water clean dishes?
This is for all the germ conscious folks that worry about
using cold water to clean.
John went to visit his 90 year old grandfather in a very
secluded, rural area of Georgia.
After spending a great evening chatting the night away,
John's grandfather prepared breakfast of bacon, eggs and
toast. However, John noticed a film like substance on his
plate, and questioned his grandfather asking, "Are these
plates clean?"
His grandfather replied, "They're as clean as cold water
can get them. Just you go ahead and finish your meal,
Sonny!"
For lunch the old man made hamburgers. Again, John
was concerned about the plates as his appeared to have
tiny specks around the edge that looked like dried egg and
asked, "Are you sure these plates are clean?"
Without looking up the old man said, "I told you before,
Sonny, those dishes are as clean as cold water can get
them. Now don't you fret, I don't want to hear another
word about it!"
Later that afternoon, John was on his way to a nearby
town and as he was leaving, his grandfather's dog started
to growl, and wouldn't let him pass. John yelled and said,
"Grandfather, your dog won't let me get to my car".
Without diverting his attention from the football game he
was watching on TV, the old man shouted ...
"COLDWATER,
GO LAY
DOWN!!!!"
Meet
Coldwater...........
.
I.



Viruses
A. Definition
Viruses: infectious particles made up of nucleic
acid, protein, and sometimes lipids
Nucleic Acid can either be DNA or RNA
Nucleic Acid is protected by a surrounding
protein capsid. (shapes on pg. 491)
Viral Structure (Polyhedral
Virus) - papilloma – warts/
cold virus
Viral Structure (Helical Virus)
-tobacco mosaic virus
Glycoprotein Enveloped
Virus – flu and AIDS



They bind to specific membrane proteins on
host.
They are much smaller (1/100 – ½) than
bacteria and can pass through filters.
No nucleus or membrane bound organelles
B. Viral Life Cycles

1. Lytic Cycle:
Viral Life Cycles (cont.)

2. Lysogenic Cycle:
C. Virus Dangers







Viruses cause polio, AIDS, influenza, &
the common cold
You cannot “cure” a viral infection; you
can only treat symptoms and prevent it
with vaccines.
Retrovirus: uses RNA; must copy genetic
info backwards (ex: AIDS)
Prions: protein infectious particles
similar to viruses only without nucleic
acids (might cause Mad Cow Disease)
Viruses do not carry out respiration
Viruses can crystallize
Viruses are obligate parasites (can not
live without a host)
II. Kingdom Archaebacteria:
Ancient Bacteria

A. Definition

a.k.a. Domain Archaea
Prokaryotes
Live in extreme conditions
Have cells walls with no peptidoglycan
Thought to be “Eukaryotic Ancestors”




B. 3 Types of Archaebacteria:
1)
2)
3)
Methanogens – produce
methane gas and live in
animal digestive tracts or
thick mud
Halophiles – means “saltloving”; live in salty
environments (like the Great
Salt Lake or Dead Sea)
Thermophiles – means
“heat-loving”; live in places
like hot springs
The 3 Types of
Archaebacteria
III. Kingdom Eubacteria





A. Definition:
A.k.a. Domain Bacteria
Prokaryotes
Live almost anywhere (very diverse)
Have cell walls containing peptidoglycan Unlike plant cells walls, Eubacteria cell walls are
made of PEPTIDOGLYCAN. Peptidoglycan is
composed of short chains of Amino Acids, or
Peptides, and Carbohydrates .
B. Prokaryote Classification
Prokaryotes are classified based
on SHAPE, CELL WALLS,
movement, and how they
obtain/release ENERGY.
 1. Shapes

– Cocci: round
– Bacilli: rod-shaped
– Spirilli: spiral-shaped

2. Cell Walls
– Types are detected using Gram Staining
– Purple = Gram positive  has peptidoglycan
– GRAM-POSITIVE BACTERIA
HAVE A THICKER LAYER OF
PEPTIDOGLYCAN IN THEIR
CELL WALLS, MADE OF A
PROTEIN-SUGAR COMPLEX
THAT TAKES ON THE PURPLE
COLOR DURING GRAM
STAINING
– Can be treated with antibiotics
– Pink = Gram negative  has 2nd outer layer
that absorbs only red stain
– GRAM-NEGATIVE BACTERIA
HAVE AN EXTRA LAYER OF
LIPID ON THE OUTSIDE OF
THE CELL WALL AND APPEAR
PINK AFTER GRAM STAINING
– Likely to resist antibiotics

3. Movement

MOVEMENT STRUCTURES
1. Many Bacteria use FLAGELLA, WHIPLIKE
STRUCTURES, FOR MOVEMENT. These are
usually used to move bacteria cells through
water.
2. Myxobacteria produce a Layer of Slime and
then Glide through.
3. Some Spiral-shaped bacteria move by a
Corkscrew-Like Rotation. These organisms
have Flexible Cell Walls and filaments within
the Cell Walls that, when Contracted, cause the
bacterium to turn and move ahead.




1)
2)
3)
4)
4. Energy Obtaining – 4
ways…
Photoautotroph – uses light
energy to produce own food
Chemoautotroph – uses
inorganic molecules to
produce own food
Photoheterotroph – needs
sunlight AND inorganic
compounds to obtain food
Chemoheterotroph – uses
products of chemical reactions
to obtain nutrition

1)
2)
3)
5. Energy Releasing –
Prokaryotes can either be…
Obligate Aerobes – requiring
oxygen
Obligate Anaerobes –
requiring NO oxygen (ex:
bacteria causing Botulism)
Facultative Anaerobes – can
function in the presence of
oxygen
C. Bacterial Reproduction


Grow and divide VERY rapidly
1. Asexually by Binary Fission
– Splitting to make 2 identical copies;
no genetic variation

2. Sexually by Conjugation
– Cytoplasm “bridge” forms between 2
bacteria allowing passage of nucleic acid;
produces genetic variation

Inunfavorable
unfavorablecondition,
condition,bacteria
bacteriacan
canform
form
3.3.In
Endospores
(resistant
internal
walls
that
allow
Endospores
(resistant
internal
walls
that
allow
them
to be
dormant
long
time
periods)
them
to be
dormant
forfor
long
time
periods)
D. What do Bacteria do?





Decompose and Recycle nutrients
Nitrogen Fixation (N2  NH3 for plant
use)
Cause Disease (Pathogens = diseasecausing organisms)
Used in the Dairy industry, in digesting
petroleum (for oil spills), for mining
minerals, and for producing drugs
Antibiotics: compounds used to kill bacteria
by destroying their cell walls