bài giảng viruses của đại học SAS

Viruses &
Viruses &
Bacteria
Bacteria
Chapter 17
Chapter 17
Biology 11
Biology 11
Presentation put together by Mandie
Presentation put together by Mandie
Lynn Walls
Lynn Walls

What are Viruses
A virus is a non-cellular particle made
up of genetic material and protein
that can invade living cells.




T4 Bacteriophage
T4 Bacteriophage

Herpes Virus
Herpes Virus




Escherichia Coli Bacterium
Escherichia Coli Bacterium
E. coli is a bacterium. That is a crude cell, it is not a virus
E. coli is a bacterium. That is a crude cell, it is not a virus
because viruses are protein containers with DNA cores or
because viruses are protein containers with DNA cores or
RNA cores.
RNA cores.


E. Coli and the
E. Coli and the
Bacteriophage
Bacteriophage
What it looks like in real life
What it looks like in real life




The Structure Of a Virus
The Structure Of a Virus

Viruses are composed

Viruses are composed
of a core of nucleic
of a core of nucleic
acid
acid

The Nucleic acid core
The Nucleic acid core
is surrounded by a
is surrounded by a
protein coat called a
protein coat called a
capsid
capsid

The Nucleic core is
The Nucleic core is
either made up of
either made up of
DNA or RNA but never
DNA or RNA but never
both
both




Cycle of Lytic and Lysogenic
Cycle of Lytic and Lysogenic

Vaccines
Vaccines
►
Viruses grown on chicken embryos are
Viruses grown on chicken embryos are
attenuated vaccines
attenuated vaccines
►
Another type of vaccine is made by heat
Another type of vaccine is made by heat
killing the virus
killing the virus


Retrovirus

Change DNA
into RNA.

Example of a
Retrovirus is
HIV


A typical, "minimal"
retrovirus consists of:
•
an outer envelope which

was derived from the plasma
membrane of its host
•
many copies of an envelope
protein embedded in the lipid
bilayer of its envelope
•
a capsid; a protein shell
containing
•
two molecules of RNA and
•
molecules of the enzyme
reverse transcriptase

Bacteria Cell


Prokaryotes

Cells that do not have a
nucleus

Exist almost every where on
earth

Grow in numbers so great you
can see them with the unaided
eye


Are placed in either the
Eubacteria or the
Archebacteria Kingdoms

Make up the smaller of the two
kingdoms






Eubacteria
Eubacteria
Make up the larger of
Make up the larger of
the two prokaryote
the two prokaryote
kingdoms
kingdoms
Generally are
Generally are
surrounded by a cell
surrounded by a cell
wall composed of
wall composed of
complex
complex
carbohydrates
carbohydrates

Cyanobacteria
Cyanobacteria

Photosynthetic
Photosynthetic
bacterium
bacterium

Bluish-greenish color
Bluish-greenish color

Contain membranes
Contain membranes
that carry out the
that carry out the
process of
process of
photosynthesis
photosynthesis

Do not contain the
Do not contain the
same type of
same type of
chloroplasts as plants
chloroplasts as plants

do
do

This bluish-greenish
This bluish-greenish
algae can be found
algae can be found
nearly everywhere on
nearly everywhere on
earth.
earth.

Can survive in
Can survive in
extremely hot
extremely hot
environments and even
environments and even
extremely cold
extremely cold
environment
environment




Archaebacteria
Archaebacteria

Lack important

Lack important
carbohydrate found
carbohydrate found
in cell walls
in cell walls

Have different lipids
Have different lipids
in their cell
in their cell
membrane
membrane

Different types of
Different types of
ribosomes
ribosomes

Very different gene
Very different gene
sequences
sequences

Archaebacteria can
Archaebacteria can
live in extremely
live in extremely
harsh environments
harsh environments


They do not require
They do not require
oxygen and can live
oxygen and can live
in extremely salty
in extremely salty
environments as well
environments as well
as extremely hot
as extremely hot
environments.
environments.




Identifying Prokaryotes
Identifying Prokaryotes
Cell Shape
Cell Shape
Cell Wall
Cell Wall
Movement
Movement


Bacterium Shapes

Cocci~ Sphere shaped
bacteria


Bacillus~ Rod shaped bacteria

Spirrillium ~ Spiral shaped
bacteria

Flagella~ Leg-like structures
that help to propel the
bacterium.




Gram + and Gram – Bacterium
Gram + and Gram – Bacterium
Cell Walls
Cell Walls




Cellular Walls
Cellular Walls

Chemical nature of a cell wall can be determined
Chemical nature of a cell wall can be determined
by Gram Staining
by Gram Staining

By finding out what color the cell produces when

By finding out what color the cell produces when
it is gram stained you can figure out the type of
it is gram stained you can figure out the type of
carbohydrates in the cell wall
carbohydrates in the cell wall

Movement
•
Flagella ~ Tail like structure
the whips around to propel the
bacterium
•
Cillia ~ Miniature flagella
surround the cell that help to
“swim”
•
Non motile ~ Sticky cillia like
structures that keep the
bacterium from moving




Flagella
Flagella

Bacteria and their
Bacteria and their
energy
energy

Autotrophs
Autotrophs

Chemotrophs
Chemotrophs

Heterotrophs
Heterotrophs