Good and Bad Bacteria - a good review
M2 Recap Blog Post at Sahm-I-Am
Kingdom Monera - bacteria
(1) p. 37-41, Bacteria
The organisms that make up kingdom Monera are all prokaryotic.
These prokaryotic cells are bacteria.
Bacteria is made up of organisms that are one tiny cell each. They are single-cellular. They can only be seen with a microscope.
So if you can actually see any living thing, you will know it is not made of only one cell, but is multi-cellular.
See these images of how prokaryotic cells may be drawn differently.
Image 1, Image 2, Image 3 (scroll down)
There may be more than one correct name of a certain part of a cell. DNA and nucleoid, for example.
Also notice fimbriae (sing. fimbria) and pili. (This is because of which job the fimbriae are doing -- bottom of p. 39)
But the main thing to know is that prokaryotic cells do not have organelles (little organs) like a eukaryotic cell does.
►See this image that compares the two kinds of cells.
--In the cytoplasm (also called cytosol) of a prokaryotic cell, there are ribosomes and DNA.
--In the cytoplasm of a eukaryotic cell, there are many organelles, each with their own job.
►Prokaryotic DNA is arranged in a winding, circular shape that connects end-to-end. There is only one replication origin (original DNA strand) when replication starts.
►By contrast, eukaryotic DNA is linear (in a line); it does not connect end to end to form a circle. The DNA in a eukaryotic cell is enclosed in a nucleus -- it is "membrane-bound." Other organelles are enclosed in membranes also, much like little water balloons of all shapes.
In eukaryotic cells, when the DNA is replicated, there are as many as 1000 replication origins.
Despite these differences, however, the underlying process of replication is the same for both prokaryotic and eukaryotic DNA.
(when used as an adjective, these words end in -ic)
The shapes of bacteria. There are three basic shapes of bacteria. (see image), source.
-Sperical (cocci), which is round.
-Rod-shaped (bacilli), which are longer.
-Helical (spirilla), which look like a spiral.
These three shapes of bacteria have variations and different groupings. (see image) source.
►Read about the size of bacteria, a single, prokaryotic cell of the kingdom Monera.
Shape and Movement of Bacteria You may not understand all this, so listen twice! (You will learn on p. 43 about anaerobic bacteria that do not need oxygen.)
Case for a Creator - Bacterial Flagellum
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(2) p. 41-44, The Eating Habits of Bacteria
A. Heterotrophic bacteria get food from other sources.
1. parisitic bacteria - parasites that feed off a living host.
2. saprophytic bacteria - feed from a non-living host; decomposes dead things for food. Saprophytes are therefore also called decomposers
B. Autotrohphic bacteria - manufactures their own food by either photosynthesis or chemosynthesis.
►Click to learn more.
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We learned about photosynthesis in Module 1.
Chemosynthetic bacteria use a different process to manufacture their food. The difference is their source of energy.
Photosynthesis uses energy from the sun.
Simply digesting food does not give us energy. In order to get energy from the food we eat, there is a complicated chemical process. That is why we breathe - so we get the oxygen needed to help perform this complicated process.
Since humans breathe, we are aerobic organisms.
However, some bacteria do not need oxygen to be able to convert their food into energy by chemosynthesis. They are anaerobic organisms. Typically they may live deep underground or in the bottom of a swamp. These bacteria help decompose dead organisms or convert useless chemicals into chemicals that can be used by other life forms. These bacteria are another essential part of God's Creation.
The growth of a population of bacteria
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(3) p. 47-50, Genetic Recombination in Bacteria
Genetic recombination in bacteria can occur in one of three ways.
- Conjugation - temporary union of 2 organisms to transfer DNA
- Transformation - transfer of DNA from a non-functional donor cell to a functional recipient cell
- Transduction - the process by which infection by a virus results in DNA being transferred from one bacterium to another
(this is the plasmid sending a strand from the donor to the recipient, not the DNA sending it)
Transformation:
Transduction:
Flu Attack! How a Virus Invades Your Body
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(4) p. 50b-51, Bacterial Colonies
Some images in your text on p. 51 are staphylococcus, streptobacillus, and streptococcus.
Staphylococcus aureus (genus and species) is the Latin name for Staph infection.
Streptococcus pharyngitis is the name for strep throat.
Others named were diplococcus, tetracoccus, and diplobacillus.
Remember bacteria can can have variations and different groupings. (see image) source.
The shape of the bacteria is in the name. Did you also notice the prefixes in the above names of bacteria? This indicates the number, and/or the way the bacteria is grouped in its colony.
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The first way we separate the organisms in Kingdom Monera is by their cell walls.
Using a Gram stain process (named after Hans Christian Gram) can tell what kind of cell wall an organism has by the the color of the cell wall after staining. (see image)
One type of cell wall will retain the dark purple stain, because it has a certain thick layer (peptidoglycan) on the outer layer of the cell.
This is called a gram-positive bacteria.
Other bacteria's cell walls have a thin layer of peptidoglycan further into the layers, and it does not retain the dark stain, and the last pinkish stain is retained.
This is a gram-negative bacteria.
►See the peptidoglycan layers in gram-positive and gram-negative bacteria. In this diagram, it is indicated by a brownish layer.
►Watch this animation of Gram stain procedure. Scroll down and read the steps on the left as the animation happens on the right. It is fast! So after you carefully read the steps, re-watch the animation of the steps. They play continuously.
Escherichia coli, commonly known as E. coli, is Gram-negative, while Streptococcus (Strep) is Gram-positive.
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(6) p. 54-56a, Classes in kingdom Monera
There are 4 phyla in kingdom Monera. The phyla are divided into classes for different reasons. Phylum Graciliacutes (Gram-negative) is further divided into classes by how they obtain food.
The phylum Firmicutes (Gram-positive) is further divided by shape. The other two phyla are not divided into classes because they each have only one class, but there is a reason they are different phyla than the first two I mentioned.
Study carefully before attempting the On Your Own 2.14.
Take notes similar to the table at the bottom of page 55.
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p. 60
Experiment 2.2, Pond Life, Part B. (Part A was preparation for this experiment.)
►At Julie's blog, see bacteria in the pond water her class collected.
►At Julie's blog, see videos of bacteria in pond water. (Experiment done in M3 - continued from M2)
►At Michelle's blog see A Microscopic World video of bacteria from their pond water.
►Michelle's class viewing bacteria in samples of pond water.
►Video -- The reaction of her class last year when they opened the stinky cultures!
We're not able to actually do the experiments, so here are some pictures of bacteria. See if you can find any names you recognize. There are two bacteria for Salmonella, but only one causes food poisoning. There are others I think you will recognize.
Here are also some videos of bacteria.
Microbiologia I
Bacteria Growth
White Blood Cell Chases Bacteria
Salmonella Cell
A video from TVschoolhouse.com. This is a great website!
►Click to watch a 10-minute video about good and bad bacteria.
In the video, he talks about 3 kinds of bacteria - parasites, saprophytes, and autotrophs.
Why doesn't he mention heterotrophs?
Because parasites and saprophytes are the two kinds of heterotrophs - bacteria which do not make their own food.
Bacteria grow best at around our body temperature or a little lower. So when you have a fever from white blood cells attacking the bacteria, that inhibits bacterial growth! God sure knows what he's doing!
Also learn about how bacteria take in food thru their cell walls.
Keep watching! =)
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