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Kingdom Monera - Bacteria Reproduction and Ecological Roles. www.onacd.ca. Bacterial Reproduction. Asexual reproduction: BINARY FISSION BUDDING. Binary Fission. 3. The cell membrane grows inward and separates the cells. The cells are genetically identical to one another .
3. The cell membrane grows inward and separates the cells. The cells are genetically identical to one another.
1. A single bacterial cell begins to make copies of its genetic material
2. The cell membrane begins to elongate and pulls the genetic material in two different directions
Most bacterial cells will grow to a fixed size and will then reproduce by binary fission
Note: equal division of cytoplasm and genetic material
Conjugation – Sexual Reproduction A primitive form of sexual reproduction where there is exchange of chromosome (red) material (genetic material) between two bacterial cells through a structure called a pili.
Examples of bacteria that are known to undergo conjugation include: E. coli, Salmonella
-plants obtain an easily absorbable form of nitrogen needed for growth.
-aid in cleaning up oil spills
symbionts in humans and other organisms.
over 1000 types of bacteria in the average
human stomach and intestines that
-immunity, vitamin absorption
and synthesis, nutrient conversion and
fermentation. (probiotic supplements contain
many of these bacteria..)
- ie. Botulism
- ie. Penicillin (a fungus) makes antibiotics
4. antiseptic – to kill most bacteria on the body surface
Penicillium fungi : produces the antibiotic penicillin
Definition: a substance produced by a microorganism that restricts the growth of another microorganism
Antibiotics that target a wide range of bacteria are termed broad spectrum. Those that target a narrow range are termed narrow spectrum.
Some antibiotics actually destroy bacteria (inhibit cell processes) whereas others keep the bacterial cell from reproducing (inhibit binary fission)
Above: Wafers containing antibiotics are placed on an agar plate of bacteria. The cloudy areas show bacterial growth. Circles of poor bacterial growth show that bacteria will not grow in the presence of that antibiotic.
Improper usage and dosaging of antibiotics also contributes to the appearance of resistant bacteria.
As close as possible to 100% of harmful bacteria must be killed off when taking a round of antibiotics. If not, the surviving bacteria will most likely carry genes that are resistant to the initial antibiotic and will then begin to multiply.
Failure to take entire prescribed dosages of antibiotics can lead to the growth of antibiotic resistant bacteria.
When antibiotics are administered when they are not needed we are exposing more bacteria to selection for resistance.
NOTE: Remember as well that the genes for antibiotic resistance can also be transferred to other normal bacteria through the conjugation.
Skin infections caused by these bacteria were treated successfully in the 1940’s and 50’s with penicillin. Presently, almost all strains are resistant to penicillin which leaves only a small section of drugs (vancomycin) to treat it.
The picture to the left shows a new form of S.aureous that is beginning to show resistance to vancomycin.
Alcohol (surgical alcohol)
Definition: antimicrobial agents applied to non-living objects that destroy microorganisms (including bacteria)
Oxidizing Agents (ex. Chlorine, peroxide, iodine…)