All living cells have certain features in common. They all are enclosed by a plasma membrane with cytoplasm held inside. They all contain nucleic acids, ribosomes and membrane transport mechanisms. Even though all of these things are in common between prokaryotes and eukaryotes, there are differences. Eukaryotes have their multiple chromosomes stored in a special…
The white blood cells that first ingest the TB bacteria are macrophages, which kill invading particles (be they cells or bits of cells, or even dead parts of your own cells) by ingesting them into a vacuole and then breaking them down. The TB gets ingested fine, but once inside the cell, it stops the cell from breaking it down. That means that you now have a white…
Bacteria and archaea are the only prokaryotes. All other life forms are Eukaryotes (you-carry-oats), creatures whose cells have nuclei. (Note: viruses are not considered true cells, so they don t fit into either of these categories.) What Difference Does It Make? Does a bacterium’s cell wall, shape, way of moving, and environment really matter? Yes! The more we know…
Structure and Function of Bacterial Cells (page 4) (This chapter has 10 pages) © Kenneth Todar, PhD The Cell Envelope: capsules, cell walls and cell membranes The cell envelope is a descriptive term for the several layers of material that envelope or enclose the protoplasm of the cell. The cell protoplasm ( cytoplasm ) is surrounded by the plasma membrane, a cell…
We compulsively wash our hands, spray our countertops and grimace when someone sneezes near us—in fact, we do everything we can to avoid unnecessary encounters with the germ world. But the truth is we are practically walking petri dishes, rife with bacterial colonies from our skin to the deepest recesses of our guts. All the bacteria living inside you would fill a…
Our Challenge: Name at least three places microbes live. Can you think of any places that microbes might not live? Microbiologists have found microbes living just about everywhere: in the soil, water and air; in animals, plants, rocks and even us! Your body is home to trillions of microbes. Run your tongue over your teeth—you re licking thousands of microbes that…
Archaeal swimming motility is driven by rotary motors called archaella. The structure of these motors, and particularly how they are anchored in the absence of a peptidoglycan cell wall, is unknown. Here, we use electron cryotomography to visualize the archaellar motor in vivo in Thermococcus kodakaraensis. Compared to the homologous bacterial type IV pilus (T4P)…
The mysterious and diverse world of bacteria just got its very own expansion pack. A total of 35 new groups, or phyla, of bacteria have been discovered in groundwater in Rifle, Colorado. The finding will likely add a bunch of new species to the tree of life — species that are quite different from other bacteria, scientists note. But here s what s really remarkable:…
At Linnaeus University Centre for Ecology and Evolution in Microbial Model Systems (EEMiS) seven research groups investigates how microorganisms interact with each other and with other organisms in their environment. Seminars Time and Place: 13.00 in A137 (if not otherwise stated) 1-2 February EEMiS Workshop 21 February Room B221 March 7 Marielle van Toor (postdoc)…
Concentrated deposits of certain substances which are presented/located in the cytoplasm of certain bacteria are known as cytoplasmic granules or inclusion bodies.They serves as storage areas for nutrients, e.g. volutin granules are reserve of high energy stored in the form of polymerized metaphosphate. The number and nature of the inclusions vary depending on the…
History of life on earth An approximate history of life on earth is shown in the table below, based on information in Encyclopaedia Britannica (1986). There may be more up-to-date information, but the major points would still apply. The evidence is fragmentary, and is obtained from three major sources: the fossil record, consisting of the preserved remains of organisms…
Organisms Present in Ballast Water Ballast water is one of the major vectors for aquatic species invasions. On any given day, it is estimated that more than 5, species of freshwater, brackish and marine organisms may be transported in the ballast water of ocean-going vessels around the world. Many studies have documented the great diversity of organisms present in…
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Asymptomatic bacteriuria means you have bacteria in your urine but you have no symptoms of infection. If you are healthy, this condition is usually not a problem and not something that your healthcare provider needs to check for. However, it can cause complications if you are pregnant, have had a kidney transplant, or have certain other medical conditions. If you…
