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Notes & Study Guide - Bacteria
There are more bacteria on this planet then everything else combined! There are more individual bacterial
cells in your mouth right now than there are mammals on the entire planet.
All bacteria are single-celled organisms that are _________________. Prokaryotic means that they do NOT
have a ______________ and they do NOT have membrane bound organelles (________________,
_________________, etc.). Bacteria are single-celled organisms that fall into two kingdoms.
Kingdom Archaebacteria – “____________ bacteria”; these are thought to resemble the first _________
__________ on Earth from a time when the Earth’s environment was very different from today. However, we
now know that these bacteria are not truly the ancient ones, but probably evolved from Eubacteria. They are
different from Eubacteria because: 1) their cell walls lack ___________________; and 2) their DNA contains
something called ____________, which are “non-coding” regions of DNA.
Most of these bacteria are thought to like __________________ environments and are classified by where
they can be ____________:
Methanogens – live in areas that are low in _____________. They produce ________________ (aka
swamp gas). They are also found in the intestines of __________.
Thermoacidophiles – These like really high ____________________ (60 – 250 C) and areas of high
_____________ (pH 2 – 4). They are found in ___________ ______________ like Yellowstone
National Park.
Chemosynthesizers – These use __________________ compounds and convert them to energy. They
are found near deep ____________ vents. They convert _____________ to energy.
Extreme Halophiles – These live in extremely ___________ conditions, where other things could not
exist. They can grow in areas up to 10 times saltier than normal _________ ____________. (Dead
Sea, Great Salt Lake)
Kingdom Eubacteria – these bacteria are different in 3 ways: 1) their cell walls contain ________________ 2)
their plasma membranes contain different __________ (fats) 3) their __________ is different.
Eubacteria are classified by several methods:
1)
Shape – rod-shaped (
); circular (
); and spiral-shaped (
)
2) Cell Wall Composition – determined by ____________ staining procedure.
Gram Positive – stain purple
Gram Negative – stain red
3) Motility – how and if they ____________ (flagella – a whiplike __________)
4) Appearance of the Colony – groups of bacteria form colonies. They can form a variety of
_____________, shapes, and _____________.
5) Respiration – Aerobic – These require ______________.
Anaerobic – Do not require ________________.
6) Metabolism – source of _______________
autotrophs
heterotrophs
chemotrophs
Bacterial Reproduction – occurs it many different ways
1. Binary Fission – ______________; produces _____________ cells. The chromosome replicates and
the cell divides. Most bacteria can double every _____ minutes.
2. Conjugation – the cell to cell ______________ of genetic material. This is a type of _________
reproduction. Two bacteria will connect using structures called ________ and genetic material is
exchanged through a _________________ bridge.
3. Transformation - This occurs when living bacteria pick up DNA from ___________ bacterial cells.
4. Transduction – This is when a __________ is used to transport bacterial DNA from one cell to
another cell.
5. Endospores – Some species develop these when conditions become ________________ for the
bacteria. Later, when conditions improve, the spore dissolves and the bacterial cell reactivates.
Treating Bacterial Infections:
Typically, bacterial infections are treated with ___________________. The word antibiotic literally means
“against living things”. These drugs usually work by disrupting the _________________ of the bacterial cell.
They can also inhibit normal protein synthesis in bacterial cells. Recently there have become cases of
______________ _______________ in which bacterial cells have acquired an immunity to the drugs that
previously killed them. This has occurred as a result of the improper use of antibiotics. Some bacterial
infections can be ______________ through the use of vaccines, in a way that is similar to viral vaccines.
The following are list of bacterial infections which have or can affected humans: