Transcript Bacteria, virus, protist, fungi Unit

Bacteria: The Monera Kingdom
• Bacteria are classified into two
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groups: Eubacteria (true bacteria)
and Archaebacteria (Ancient
Bacteria).
They are autotrophic or heterotrophic
most numerous organisms on earth
simplest and smallest organisms.
they are now part of nearly every
environment on Earth.
found at the bottom of the oceanic
trenches and in Arctic and Antarctic
Regions.
about 2.5 Billion Years Old and
Modern Humans arose about 100,000
years ago.
organisms are classified as Bacteria
by having only one characteristic :
they lack a nucleus.
Bacterial Structure
Shape of Bacteria
• Cocci – sphere
• Bacilli – rods
• Spirilla - spirals
Bacilli
Cocci
Spirilla
Structures that help bacteria survive
in hostile environments
• capsules (slime
layers) - help evade
immune system,
adhere to surfaces
and prevents from
drying out.
• endospores -
bacteria become
dormant until
conditions become
favorable
Movement of Bacteria
• flagella - one or
more whip-like
structures that
beat their way
through the
water.
• Spiral their way
through the water
like a corkscrew.
Gram Stain
• Gram's Stain is a
method of staining
bacteria as an aid to
their identification. It
was originally
devised by Hans
Christian Joachim
Gram, a Danish
doctor.
• Gram Negative -light red or pink
color
• Gram Positive -dark purple
Gram Negative
Gram Positive
Reproduction
• Binary fission - one cell
splits into two cells,
• Conjugation - bacteria
exchange genetic information
before dividing, offspring
have new genes (and new
traits)
• Transformation - bacteria
incorporate genes from dead
bacteria
• Transduction - viruses
insert new genes into
bacterial cells.
Binary fission
Conjugation
Transformation
Transduction
Viruses
Some properties of viruses
• posses no membranes,
cytoplasm, ribosomes, or
other cellular components
• they cannot move or grow
• they can only reproduce
inside a host cell
• they consist of 2 major parts
- a protein coat, and
hereditary material (DNA or
RNA)
• they are extremely tiny,
much smaller than a cell and
only visible with advanced
electron microscopes.
Review the
structure of DNA
• Recall that DNA is a double helix
molecule. It is composed of
alternating sugars (deoxyribose)
and phosphates.
• The "rungs" of the ladder are made
of nucleotides: adenine, thymine,
guanine and cytosine.
• These nucleotides make up the
genetic code - or blueprint- for the
organism.
• Viruses are made of DNA and a
protein coat, since they do not
actually grow, reproduce (on their
own) or carry out other life
functions, they are not considered
to be living organisms
Host of Viruses
• Viruses are specific to
their hosts. They can
only attack specific
cells, and not all viruses
can pass between
different species
(though some can).
Rabies, for instance, can
be passed from animal
to human. HIV is a virus
that seems specific to
humans.
T-Even virus attacking a cell
Common Cold & HIV
• The common cold is a
virus that specifically
attacks cells of the
respiratory track
(hence the coughing
and sneezing and
sniffling).
• Other viruses attack
other types of cells.
HIV virus specifically
attacks white blood
cells.
Rhinovirus- common cold
Related to Viruses
• Viroids - even smaller than
viruses, consist of RNA
strands that lack a protein
coat. Viroids mainly cause plant
diseases.
• Prions - infectious agents
that are believed to be the
cause of Mad Cow Disease,
relatively new find and
This is your Brain
much is not known about
them. All diseases known to be this is your Brain on Beef
of prion related, occur in animals
• Bacteriophage - viruses
that infect bacteria.
Viral Replication
• Viruses multiply,
or replicate using
their own genetic
material and the
host cell's
machinery to
create more
viruses.
• Viruses cannot
reproduce on
their own, and
must infect a host
cell in order to
create more
viruses.
Retroviruses
• Retroviruses have RNA and the
enzyme reverse transcriptase instead of
DNA as their nucleic acid core.
• Once inside the host cell, reverse
transcription (making DNA from RNA)
is accomplished by the reverse
transcriptase, turning the singlestranded RNA into DNA.
• This new DNA is incorporated into the
host DNA, where it transcribes new
viral RNA genomes, as well as the
RNA to synthesize new reverse
transcriptase and protein capsules.
• The human immunodeficiency virus
(HIV), a retrovirus associated with
AIDS, replicates in this way.
Virus Replication Web Link
http://www.hivinfosource.org/animation.ht
ml
Protist
• eukaryotes that
include unicellular
and multicellular
organisms
• Include autotrophic,
heterotrophic, and
parasitic organisms.
• contains the
protozoa, algae, and
fungus-like protist.
Where does the kingdom name
"protista" come from?
• The Kingdom Protista was the third
kingdom named. At the time, the
other two kingdoms were for animals
or plants. Some scientists wanted to
include these organisms in the plant
kingdom and others protested and
wanted to place them in the animal
kingdom. Eventually, a compromise
was reached. They were all placed
into a third kingdom, the Protists.
Protozoa (animal-like)
• often microscopic (unicellular)
•Many relationships from - free
living, parasitic, saprophytic,
mutualistic
•Cannot make their own food
•Often classified by how they move
-Amoeba - moves with
Pseudopods (false feet)
-Paramecium - moves by cilia
-Flagellates - move by the
whipping flagella tails.
-Sporozoans – moves by the fluid
of the host they live inside of.
Amoeba
Paramecium
More Protozoans
• Phylum Sarcodina
– Pseudopods (false
feet) projections of
cytoplasm.
– Some surrounded by a
calcium "shell"
– Amoeba has no
definite shape
– feed by phagocytosis-they flow around their
prey (usually a smaller
cell) and engulf it.
Amoeba
Ciliates
• Phylum Ciliophora
– Moves using cilia short hairs lining cell
– use cilia to sweep
food down into their
central channel or
gullet.
• Other Ciliophora
– Stentor
– Vorticella
– Spinostomium
Paramecium
Stentor
Flagellates
• Phylum Mastigophora
– Moves by long whip-like
hairs.
– Often have more than one
flagellum
– The organism which causes
African sleeping sickness carried by the testie fly
– Some live in the digestive
tracts of termites and assist
in the digestion of
cellulose.
Trypanosoma blood parasite
Causes African sleeping sickness
Trichonympha (in termite guts)
Sporozoans
• Phylum Sporozoa
– No means of movement
– can be transmitted through fluids
from one host to another.
– Most sporozoan are sporeforming parasitic (Harmful)
protozoans.
• Plasmodium
– Causes malaria, its life cycle
include stages in both the
mosquito and humans
Algae (plant-like protist)
• All algae contain
chlorophyll and carry
out photosynthesis
• Vary in color and often
named by its color.
• Most live in water,
some on damp surfaces
• Make up a large part of
the plankton of the
oceans
Euglena
• Phylum Euglenoids
– Most are unicellular
– Possess movement
like animals
– Move by using whip
like tail called
flagellum (one only)
– Reproduces asexually
– Has eyespot to detect
sunlight.
Diatoms (golden algae)
• Phylum Chrysophyta
– Two part shell of
silicon (glass)
– Food stored as oil
– Responsible for most
oil consumed today
– Forms the
diatomaceous earth.
These deposits are
mined commercially as
abrasives and filtering
aids
Dinoflagellates (fire algae)
• Phylum Pyrrophyta
– Surrounded with
"plates"
– Has two flagella
– bioluminescent
algae
– Responsible for "red
tides"
– Contains toxins
Other algae or plant-like protist
• Chlorophyta
– Green algae
– Mostly freshwater
– Multicellular (some unicellular
– Seen as algae bloom in ponds
• Phaeophyta
– Brown algae
– Multicellular
– Marine protist
– Seaweed (giant kelp)
• Rhodophyta
– Red algae (produces agar)
– Multicellular
– Marine protist
Green algae
Spirogyra
Brown algae (giant kelp)
Red algae
Fungus-like Protist
• Slime Molds
– Live in moist soil and
on decaying plants and
trees
– Very colorful
– blob of protoplasm
– really nothing but a
large amoeba and
feeds much the same
way, by engulfing its
food (mostly bacteria)
with pseudopodia.
the dog vomit slime mold
Fungi
Mycology - Study of fungi
• multicellular organisms, some
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unicellular(yeast)
get their food through the
absorption of organic nutrients
Saprophytes - organisms that
lives on dead organisms and
decompose them
Parasites - feed on living
things
together with bacteria, they
allow the recycling of dead
organisms into the
environment
mushrooms, molds and yeast
are common examples of
fungi.
Basic Fungus Groups
• Zygomycota
– Common molds
• Ascomycota
– Sac fungi
• Basidiomycota
– Club fungi
• Deuteromycota
– Imperfect fungi
• Oomycota
– Water molds
Zygomycota
• Common Molds
– Black bread mold
– filamentous fungi which
are terrestrial growing on
moist, dead organic matter.
– body is called a mycelium;
it is made up of
interwoven, thread-like
structures called hyphae.
– Reproduces both asexually
and sexually.
Common Mold
Bread mold
Ascomycota
• Sac Fungi
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cup fungi
yeast (unicellular)
cup fungi
morals
truffles
most reproduces
sexually, yeast
reproduce asexually by
budding
yeast
morals
Basidiomycota
• Club Fungi
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Mushrooms
puffballs,
Bracket fungi
Wheat rusts
Reproduces mostly
sexually.
bracket fungi
puffballs
Amanita Fly
(poisonous)
Deuteromycota
• Imperfect Fungi
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Penicillium
Aspergillus
Ringworm
Athlete’s foot fungus
reproduces asexully
only(this is why it is
called imperfect)
Ringworm
Athlete’s foot fungus
Oomycota
• Water molds
– Downy mildew
– Potato blight fungus
– Reproduces both sexually
and asexually.
Common water mold
Potato blight fungus
Fungus Economic Importance
– yeast is used widely by brewers and bakers to
prepare alcohol and in raising bread.
– some mushrooms are used as food for their
delicacy and high nutritive value.
– the fungus Penicillium is used for the
production of antibiotic penicillin.
– few species are used to give flavor and texture
to cheese.
Fungus Ecological Significance
– If it was not for the actions of decomposers,
nutrients would get locked up in the dead
matter of organisms.
– Life on earth without these organisms
eventually would become impossible.
Lichens
– It is an association between
an alga and a fungus, which
together form a closely
integrated unit.
– The body of a lichen is
composed of branching
hyphae of a fungus, which
harbor algal cells.
– The fungus gets food
by the alga and the alga in
return gets shelter, moisture
and minerals absorbed by the
fungal partner.
- Found on rocks, tree trunks
and walls
Lichens Economic Importance
– Some lichens are valuable source of food to
wild animals like reindeer.
– Some lichens are fried and given to cattle as
food and to some extent to human beings.
– Some are used in medicines and other are for
preparation of dyes.
– Litmus is prepared from certain lichens and
some are also used in the preparations of
cosmetics and perfumes.
Lichens Ecological Significance
– Lichens growing on rocks disintegrate them to
form soil, preparing the ground for mosses and
subsequently for higher plants. Thus, they help
in the succession of plant communities.
– Acts as pollution indicators.