Characteristics of Monera
All organisms that fall into the Moneran kingdom are considered prokaryotes. They are the simplest and earliest life forms on the planet. Bacteria are part of the Moneran kingdom. All members of the kingdom Monera have no nuclei in their cells. All genetic material in these cell floats around in the cytoplasm. They have plasmid DNA. Monerans reproduce both sexually and asexually. digest their food outside of the cell and then absorb the nutrients. Some of them generate their own food by making it. Others need to feed off of other organic matter, such as decaying material. Some monerans are parasites that feed off of a host and others create a symbiotic relationship with another organism. Monerans reproduce both sexually and asexually.
Gram Stain
Gram Stain is the staining of bacteria with a dye, usually crystal violet, which stains all bacteria purple. Scientists use iodine on the bacteria for about 1 minute and this will act to fix the dye onto the bacteria. Next the slide the bacteria is one is flooded with a solution of alcohol and acetone for 30 seconds. What this does is all of the dye in the Gram negative cell walls have been washed away by the alcohol, acetone, or even 95% ethanol can be used. This is because the gram negative cell wall, while it does have a layer of peptidoglycan it is significantly thinner than gram positive bacteria. The final step is to stain the bacteria again using safranin which is a red dye. This will stain the Gram negative bacteria pink, and since the Gram positive has not lost their purple dye, the lighter red color shouldn't change with the Gram positive bacteria's color. So basically the stain works by coloring both bacteria, the thick peptidoglycan sucks up the purple dye and keeps it while the thinner peptidoglycan cells lose the purple dye and then retain the red dye. These tests are extremely important to doctors because it helps them as a first identifier to bacterial diseases.
Reproduction
Transformation - is a form of genetic recombination in which a DNA fragment from a dead, degraded bacterium enters a competent recipient bacterium and is exchanged for a piece of DNA of the recipient. When a bacterial cell dies, it can break open, releasing its DNA which can be picked up by a similarly related species, and incorporated into their genomes.
Transduction - is when a bacteriophage would attach onto a bacteria. It inserts its DNA into the bacteria. However, in transduction instead of the virus replacing the DNA is combines with it. So, when the viruses grow from inside the cell and burst out, the new viruses will carry the combined DNA from the original bacteria to the new bacteria.
Conjugation - In conjugation, a bacterial cell will transfer genetic information directly into another bacterial cell. One cell grows a pilus, or tube, which connects another bacteria. A plasmid then passes through the pilus into the other cell. The plasmid is then incorporated into the recipient cell.
Binary Fission - During binary fission, the single DNA molecule replicates and the original cell is divided into two identical cells. Binary fission begins with the single DNA molecule replicating and both copies attaching to the cell membrane. Next, the cell membrane begins to grow between the two DNA molecules. Once the bacterium just about doubles its original size, the cell membrane begins to pinch inward. A cell wall then forms between the two DNA molecules dividing the original cell into two identical daughter cells.
Transduction - is when a bacteriophage would attach onto a bacteria. It inserts its DNA into the bacteria. However, in transduction instead of the virus replacing the DNA is combines with it. So, when the viruses grow from inside the cell and burst out, the new viruses will carry the combined DNA from the original bacteria to the new bacteria.
Conjugation - In conjugation, a bacterial cell will transfer genetic information directly into another bacterial cell. One cell grows a pilus, or tube, which connects another bacteria. A plasmid then passes through the pilus into the other cell. The plasmid is then incorporated into the recipient cell.
Binary Fission - During binary fission, the single DNA molecule replicates and the original cell is divided into two identical cells. Binary fission begins with the single DNA molecule replicating and both copies attaching to the cell membrane. Next, the cell membrane begins to grow between the two DNA molecules. Once the bacterium just about doubles its original size, the cell membrane begins to pinch inward. A cell wall then forms between the two DNA molecules dividing the original cell into two identical daughter cells.
Harmful Bacteria Examples
Streptococcus pyogenes
Streptococcus pyogenes causes strep throat and tonsillitis
Streptococcus pneumoniae
Streptococcus pneumoniae causes pneumonia
Mycobacterium tuberculosis
Mycobacterium tuberculosis causes tuberculosis
Useful Bacteria Examples
Escherichia coli
E. Coli is found in the intestines of humans and aids them in digestion.
Streptomyces
Streptomyces is used in making antibiotics
Lactobacillis Acidophilus
Lactobacillis Acidophilus is found in yogurt. It helps support a healthy digestive system.
Antibiotics
Most bacteria produce a cell wall that is composed partly of a molecule called peptidoglycan. Peptidoglycan is made up of amino acids, sugars and short peptides. Human cells do not make or need peptidoglycan. Penicillin, one of the first antibiotics, prevents the making of peptidogyclan. Without the macromolecule there is no cell wall, so cell becomes very fragile and will bursts, killing the bacterium. No harm comes to the human host because penicillin does not inhibit any biochemical process that goes on within us.
Structure of Bacteria
- Average bacteria 0.5 - 2.0 um in diameter.
- Volume is ~4 um
- Due to its small size food can enter through the cell membrane quickly to reach all parts of bacteria
- Eukaroytes need structures & organelles
- Parts - flagellum (moves the bacteria), plasmid (has DNA), cell membrane (surrounds the cell and regulates what goes in and out), cell wall (protects the bacteria), chromosome (coiled up DNA molecules), pilus (hair like surface, acts like a whisker), ribosome (makes protein), inclusion(storage vessels), capsule (helps protect, and digest)
- Eukaryotes are similar to prokaryotic because they both have DNA as their genetic material, they are both membrane bound, they both have ribosomes, they have similar basic metabolism and they are both amazingly diverse.
Basic shapes
Coccus
Coccus
Bacillus
Bacillus
Spirillum
Spirillum
Three Domain Systems of Classification
The three-domain system adds a level of classification above the kingdoms present in the five-or-six-kingdom systems. The current system has the following kingdoms in the three domains: Archaea, Bacteria and Eukarya. The 5 kingdom system has the following: Monera, Protista, Fungi, Plantae, Animalia. They both each classify due to how many cells are there, and how the cell is structured. However, The 5 Kingdom system is more specific to physical characteristics.The 3 domain system allows one to go back further and recognize a common ancestor. It is based on modern molecular evidence.