Download Monerans / Bacteria

Monerans / Bacteria
Smallest and simplest living organisms.
IRP INFO
Characteristics of Bacteria
Kingdom Monera is now classified as Bacteria.
They are the simplest forms of undisputed living organisms.
Metabolically active, nutritional requirements, produce wastes,
reproduce, can be killed.
All Bacteria are classified as PROKARYOTIC.
Do you remember what the characteristics of Prokaryotic cells
are? Ask a friend.
The characteristics are….
Prokaryotic Characteristics
and Cell Structure.
Unicellular
Lack organelles with membranes (What’s an organelle
again?)
No true nucleus. Do contain chromosomes and Plasmid.
Smallest cells we know of
Cell structures include: cell wall, cell membrane, nucleiod
region, ribosomes, flagella, cytoplasm.
Basic Bacteria Diagram.
Features in detail
Biochemical structure of their cell walls is one of the
differences which separates many of the bacteria.
Walls are made of protein and carbohydrates and
sometimes lipids.
We use Gram’s Stain to identify these characteristics
microscopically.
Gram’s Stain is made of a purple and red dye.
Protein/Carb will be coloured purple (Gram Positive)
Lipid layers will be coloured red (Gram Negative)
Continued.
Many bacteria will also secrete a sticky material around
their cell walls
This provides some protection and holds them together
to form colonies. How is a colony different than a multicelluar organism?
PILI: surface chemicals that allow bacteria to join
together to conduct processes.
FLAGELLA: long thin protein filaments which are
rotated to provide movement.
This motility allows bacterial to move towards or away
from stimuli.
Basic Shapes.
Spherical called coccus
Streptococcus (strep throat) Pneumococcus (pneumonia)
Rod called bacillus
Escherichai Colio (E. coli)
Sprial shaped called spirillus
Treponema pallidium (Syphilis)
Caption: colony
of bacteria,
Salmonella
enteritidis,
cause of a severe
outbreak of food
poisoning in
Britain in 1988.
The outbreak
was traced to
chicken eggs
containing the
bacteria.
Caption: Serratia marcescens showing long flagella and numerous but less
prominent pili. Serratia marcescens is a rod-shaped, bacterium associated
with nosocomial or hospital related infections. Serratia marcescens colonize
in the respiratory and urinary tracts of adults causing nosocomial
bactermia, catheter-associated bacteremia, urinary tract infections and
wound infections. The bacteria can also be found in the damp environment
of bathrooms as a pink, slimy film that can be killed with bleach.
Magnification: 30,000x
Distinguishing Bacteria
Three basic divisions based on their requirement of the
presence or absence of oxygen.
AEROBIC: Require oxygen for cellular respiration.
Most bacteria fall under this category.
ANAEROBIC: Thrive without Oxygen
Facultative anaerobes: Typically aerobic, but have the
ability to function in the absence of oxygen as well.
a few notes on Aerobic and Anaerobic
Cellular Respiration, (remember, the process where
our cells get energy by breaking bonds in the food we
eat) is considered an aerobic process.
We can still metabolize nutrients in an aerobic
environment though.
Our muscles still work even when they don’t get enough
O2, however its much less efficient.
The bi-product is lactic acid which makes your muscles
sore until they get enough O2 to break it down.
Anaerobic process around you.
There are several common processes that happen
without oxygen that you are probably familiar with.
1. Our own muscles creating lactic acid but still
function with an oxygen deficit.
2.Anaerobic respiration is referred to as Fermentation
Used in cooking and producing alcohol.
Yeast (which is actually a Fungi) are used.
Additional Distinctions
Once again we look at how an organism gets in
nutrients.
There are two divisions which we have discussed with
respect to the other kingdoms.
They are:
Autotrophic
Photosynthetic and chemosynthetic.
Heterotrophic
Most bacteria get their energy from the environment
around them.
Thinking Break
From what you already know about bacteria, would you
say most bacteria is positive or negative to the world
around us? Is it harmful or beneficial to humans?
Environmentally Helpful
The vast majority of bacteria are helpful. Disease is caused
by only a few of them. Water, food, and air carry bacteria
from one person to another.
Beneficial bacteria have also found their uses in other
places. In today’s world, the environment and its related
issues are steadily gaining a lot of importance. It has been
seen that helpful bacteria are useful in dissolving organic
sludge from water, breaking down the growth of algae,
reducing the various noxious odors such as hydrogen sulfide
odors, reducing ammonia levels, promoting faster growth of
fish in the water body, and also defeating unhealthy
bacterial growth in the water body.
Personally Helpful
Helpful bacteria
Certain types of bacteria live in the intestines of human beings. They help in digestion and in
destroying the harmful organisms. Intestinal bacteria also produce some vitamins required by the
human body.
Certain bacteria help break down lactose in the digestive tract.
It is observed that Infants who were administered the bacteria Lactobacillus reuteri or
Bifidobacterium had fewer and shorter episodes of diarrhea.
Fermented milk containing the live bacteria Lactobacillus casei helps in eradicating harmful
bacteria Helicobacter pylori in children.
Some bacteria present on the skin protect us from the spread of certain fungus.
It was found that DNA damage was significantly reduced by all six strains of lactic acid producing
helpful bacteria tested with the exception of Streptococcus thermophilus.
Continued.
There are many types of bacteria that live inside the mouth, nose,
throat, and intestines of humans and animals. These bacteria get a
place to live and feed while keeping other harmful microbes from
taking up residence.
Certain stomach bacteria may work harmoniously with our
immune system. There are billions of stomach bacteria, which are
friendly or beneficial bacteria.
There are some friendly bacteria such as intestinal flora or micro
flora which are good for human health. These healthy stomach
bacteria are helpful to release many useful vitamins such as
vitamin B and vitamin K, etc. The most important task that
stomach bacteria do is to maintain normal pH level or acid level
of human stomach.
Bacterial Reproduction
We discussed the unique life cycle of a virus.
Lytic and Lysogenic cycles. Review with a partner.
Dependant on host cell: Debate around living organism.
Most Bacteria reproduce through a process call BINARY
FISSION:
Specialized type of mitosis where unicellular organisms divide
inorder to reproduce.
Multicelled organisms use mitosis for regular growth and meiosis
for sexual reproduction.
Bacteria can divide as often as every 20 minutes.
Do the math. How many bacteria would you have after 8
hours?
Exponential Growth.
This constant doubling of a population can lead to
exponential growth of a bacteria.
Remember exponential growth?
In 1 hour there would be 8
2 hours 64
3 hours 512
4 hours 4096
5 hours 32,768
Conjugation
When things are great around a bacteria and binary
fission isn’t the best option, Bacteria maybe prompted
to reproduce in a type of “sexual” reproduction* called
CONJUGATION: DNA is replicated and transferred
into another bacterial cell. The host cell can then
incorporate the new genetic material into its own
chromosomes.
Take a minute and compare and contrast the benefits
conjugation vs binary fission?
*the cells will still divide in order to reproduce asexually.
When times get real tough…
If things get really bad for bacteria they have a last
resort.
Bacteria can produce an “inner cell” called an
ENDOSPORE.
Endospores contain a replica of the cells genetic
material and stores it in a very durable cell wall.
The parent cell may die, but when things get good
again, the endospore may become active again and
produce a new copy of the bacteria.
A little bit of science history
For the last several decades we have become
germaphobes. Is it a chicken / Egg situation do you
think?
Although bacteria has been extremely beneficial to
humans, some strains have of course been quiet
harmful.
Science has worked dilligently to create new ways to kill
bacteria both inside our bodies and outside as well.
Terminology
You have heard the following terms used with respect
to health and sterile environments but perhaps never
realized their distinctions.
Antibiotics
Antiseptic
Disinfectants
All three terms are generally used interms of killing
bacteria.
ANTIBIOTICS: Kill bacteria inside the body.
ANTISEPTICS: Kill bacteria on the surface of the body
DISINFECTANTS: Kill bacterial on non-living surfaces
Continued.
Because bacteria are relatively simple organisms who
multiply quickly and often, the chance for a mutation
to happen and spread is very common.
These MUTATIONS or genetic typos create new
strains of the bacteria. This is very evident with respect
to the medical community and you may have heard the
term Antibiotic resistant bacteria.
One season Antibiotics may be very effective against a
bacterium, however not all are killed. Those possessing
genetics which allow them to survive an antibiotic or
which have mutated so antibiotics are no longer
effective may now reproduce and new antibiotics must
be created.
Ecological Roles of Bacteria
ECOLOGICAL ROLE: how bacteria affect or interact with
other organisms.
As we have discussed not all bacteria is bad, even some of
the ones we think of as harmful serve an important purpose.
E. coli as a symbiotic relationship… Hog wash!
What is our current perception of E. colio?
When E. coli remain in the large intestines where they
belong they actually produce vitamin K and minerals for
mammals to absorb as they break down fecal matter. BiWinning!
Loose Ends
Not all bacteria depend on another living organisms.
Some are FREE-LIVING.
Bacteria can be DECOMPOSERS like fungi and
worms and serve an extremely important role in freeing
the locked up chemical elements and nutrients of
organic remains and organisms.
NITRIFYING BACTERIA actually take Nitrogen out
of the air and put it into a usable state for plants so
that it can be put back into the food chain.
Nitrogen is required by all living organisms to create
proteins and nucleic acids.
A quick note on Biotechnology
Because of bacteria’s unique properties:
Simple, asexual reproduction, basic genetic material and
ability to produce proteins (unlike viruses)
Science is becoming increasing aware of the benefits that
bacteria can serve.
Through a processes called RECOMBINANT DNA
scientists can insert desired DNA into a bacteria in
order to turn them into mini factories! Insulin is
produced in this fashion.
Videos….finally.
Oil Eating Bacteria?
http://video.foxnews.com/v/4273359/oil-eatingmicrobes
http://www.youtube.com/watch?v=mDkCqmv2GVU
&feature=related