Microbiology Review

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22 Φεβ 2013 (πριν από 4 χρόνια και 4 μήνες)

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Microbiology Review

Taxonomy


Microbiology

-

is the study of micro
-
organisms




Microorganism

-

any living thing that is too small to be



seen
with
the
naked
eye.


found
in the air, water, on plants or animals, and on people




some can make you sick, but most are harmful, and a few are beneficial.




Prokayotic

-

a type of cell that does not have its



chromosomes
surrounded by
a
nuclear envelope




Eukaryotic

-

a type of cell that has a true nucleus, surrounded


by
a nuclear
envelope




Heterotroph

-

an organism that obtains energy by eating other


organisms




Autotroph

-

an organism that obtains energy directly from


light



Taxonomy


Scientists classify microorganisms
into 5 different groups:


Viruses (not considered “living”)


Kingdom
Eubacteria


Kingdom
Archaebacteria


Kingdom
Protista


Kingdom Fungi


Viruses


Viruses

are very small, lifeless particles that carry out no
metabolic functions (don’t breathe, no cellular respiration) and
cannot reproduce without assistance.




In order to be able to reproduce the virus must invade a living
cell
.



Viruses are more simple in structure than living organisms


Instead of a cell membrane like living cells, viruses have a
protein coat called a
capsid


Inside the
capsid

is the nucleic acid (DNA or RNA)




A unique type of virus is a
bacteriophage
, which only infect
bacterial cells.


Bacteria

1.

Kingdom
Eubacteria






prokaryotic

(simple organisms lacking nuclei


composed of 1 cell (single
-
celled organism)
that does not contain a cell nucleus


can be either
autotrophs

or
heterotrophs


reproduce by asexual reproduction


live nearly everywhere


can cause disease


e.g. Bacteria and Blue
-
green algae


Bacteria

2.
Kingdom
Archeabacteria




Prokaryotic


Heterotrophs

or
autotrophs


Live nearly anywhere including salt
lakes, hot springs, animal guts


Do not cause disease


Incude

methanogens
,
thermophiles
,
halophiles


Bacteria Shape

A)
Cocci



spherical
---


B)
bacilli


rod
-
shaped
---------------


C)
Spirilla



spiral


Bacteria Configuration

Fighting Disease


Review

the 3 levels of defense


External


Lymphatic System


Antibody Formation


Review

types of immunity


Passive


Active

Kingdom
Protista


Protozoa
-

Greek name meaning

first animal




Eukaryotic
-

membrane bound
organelles
and a
true nucleus



Most unicellular



Some autotrophic, some
heterotrophic,
some can
switch
between both types
depending upon
environmental conditions


3 Main Groups Protists

1.
Animal Like Protists


Protozoans


unicellular


most
are motile
-

living in
aquatic environments


heterotrophic


food broken
down in food vacuoles


reproduce
by binary or
multiple fission or conjugation


adaptations
to survive in a
variety of environments


Eyespot


Cyst


Contractile
Vacuole



Rhizopods


move
by pseudopodia
(
cytoplasmic

streaming)


engulf
food with pseudopodia


some
have mineral skeletons
(tests)




Ciliates


move by beating cilia


food is swept into cell’s gullet
by cilia


the most complex
protozoans


require two or more nuclei



Flagellates


move by beating flagella


most live within other
organisms



Sporozoans


do not move physically


spores form for reproduction


spores move from host to
host (parasitic)


2.
Plant Like Protists


mostly
autotrophic


live
in soil, on the bark
of trees, in fresh water,
and in
salt water


produce
most of the
atmospheric oxygen


form
the base of
aquatic food chains


reproduce
asexually
and sexually


unicellular
,
multicellular
,
or live in colonies


Examples:


Euglenoids


Dinoflagellates


Algae


Diatoms
(
Bacillariophyta
)


Golden Algae
(
Chrysophyta
)


Green Algae
(
Chlorophyta
)


Brown Algae
(
Phaephyta
)


Red Algae
(
Rhodophyta
)


3.
Fungus
-
Like Protists


heterotrophs
, they secrete digestive juices
and
then absorb
the organism

•have cell walls

•use spores from fruiting body to reproduce

•unlike fungus, they can move at some
points in
their life
cycle



Oomycota

(Water Moulds and Mildews)


Slime Moulds

Kingdom Fungi


Includes:


i.
Chytrids (water mould)

ii.
Common moulds (bread mould)

iii.
Yeast, morels & truffles

iv.
Mushrooms

v.
Club
-
shaped (parasitic fungi)


The parts designed for nutrient absorption are often
underground (called mycelium)


A mesh of microscopic filaments that branch out just
below the surface


Each filament in the mesh is called a hypha


The cell walls of hyphae are often reinforced with chitin


Some hyphae contain cross
-
walls


Microorganisms in
Ecosystems


There are three types of symbiotic
relationships:


Parasitism (+/
-
)


Commensalism (+/0)


Mutualism (+/+)

Microorganisms in
Biotechnology


Biotechnology

is the use of living organisms for
commercial applications


R
ecombinant DNA
-

used to insert DNA from other
organisms in to bacteria (see human insulin diagram)


Also used to improve plant crops


Resist pests


Improve taste


More nutrients


Longer shelf
-
life


Viral Vectors
-
this
method takes advantage of the
virus’ attack plan


Recall
that they ingest their DNA into the host cell to
“hijack” it.


Only works with cells that are dividing


Will not work with brain and spinal cord cells