Download Bacteria QA File

Biology 2201
In-Class Questions
November 27th
Refer to “Mainly Microorganisms”, pp. 130-139
1.
What are the two kingdoms in which Bacteria
are classified?
The two kingdoms are Kingdom Archaea and Kingdom Eubacteria.
2.
Since all of the bacteria are in fact “Bacteria”, why are there two kingdoms?
There are two kingdoms because Archaea are as different from Eubacteria (genetically and biochemically) as they are
from Plants and Animals.
3.
What are the three shapes of bacteria in the Kingdom Eubacteria?
The three shapes seen in Eubacteria are (i) cocci (round), (ii) bacilli (rod-shaped) and (iii) spirilli (spiral shaped)
4.
Do members of the Kingdom Archaea have the same shapes (body form)?
Yes, Archaea do have the same three shapes as Eubacteria, but they also may have a square or triangle shape.
5.
What are two of the methods by which bacteria reproduce? Of these two, which one
occurs most often?
The two methods by which bacteria reproduce are binary fission (asexual reproduction) and conjugation (sexual
reproduction). Of these two, binary fission is the more common method, and occurs whenever a bacterium is in ideal
conditions.
6.
Are all bacteria pathogens? What exactly is a pathogen?
A pathogen is any disease causing organism. Many bacteria are not pathogens; quite a few of them actually make human
life better, such as the bacteria that aid in decomposition of dead and decaying matter, the bacteria that live within our
digestive systems, and the bacteria that allow us to make certain foods, such as yoghurt.
7.
Food poisoning may be caused by Clostridium botulinum. How would you prevent
growth of this organism?
To ensure that bacterial endospores are killed, food must be heated under high pressure at temperatures above the
boiling point of water.
8.
What good is an antibiotic?
Antibiotics are drugs designed to prevent bacteria from growing and reproducing. This prevents the bacteria from
spreading, and eventually will rid the bacteria from the body of the affected person.
9.
Why should your doctor make sure you have a bacterial infection before prescribing
any drugs?
This is important because antibiotics are only effective against bacteria. If you are sick as a result of any other type of
pathogen, the antibiotics will not be helpful. In fact, over-use of antibiotics can actually be dangerous to future use of
these drugs, because bacteria can develop a resistance to these drugs. When this happens, the bacteria will not be killed
by the use of antibiotics, and the diseases they cause will have no treatment.
10.
What characteristic of Archaea cell walls makes them able to withstand extremely
high or extremely low temperatures?
The cell walls of archaea have a different structure and chemical composition than those of bacteria; they do not contain
peptidoglycan. The cell walls of some archaea contain unusual lipids, which remain stable at very high temperatures.
Archaea that function at low temperatures have high contents of other fatty substances that remain fluid and functional at
cold temperatures.
11.
Explain what the following terms mean:
(i)
Methanogen - methane producing bacteria that live in oxygen-free environments
(ii)
Halophiles – salt-loving bacteria that live in extremely salty environments
(iii)
Thermoacidophiles – heat and acid loving bacteria that live in hot and acidic environments.