Download Kingdoms Eubacteria and Archaebacteria

Kingdoms Eubacteria and Archaebacteria - Answers
1. Archaebacteria, commonly called ancient bacteria lives and thrives in
environments that are normally not conducive to life and often do not contain
oxygen. They can be found in swamps and habitats with high salt contents such
as the Dead Sea. They also live in habitats with high temperatures and high
acidity such as near underwater thermal vents and sulfur springs.
2. The three main groups of archaebacteria are methanogens, extreme
thermophiles, and extreme halophiles. The methanogens are bacteria that
produce methane gas. The thermophiles live in environments with extremely hot
temperatures (up to 110°C). The halophiles live in environments that have a high
salt content.
3. Although they are now classified into separate kingdoms archaebacteria and
eubacteria still share many common characteristics. All bacteria are prokaryotic
and are single celled organisms. They are lacking membrane bound organelles
such as mitochondria and nuclei. They have a single chromosome and they
reproduce asexually by binary fission.
4. Eubacteria are classified based on three basic shapes. There is spherical
(plural: cocci; singular: coccus), rod-shaped (plural: bacilli; singular: bacillus) and
spiral (plural: spirilla; singular: spirillum)
5. Bacteria reproduce by dividing into two new bacteria (binary fission) and will
often remain together in groups or clusters however some will remain as
individual cells.
6. Generalized structure of a bacterium:
7. Bacteria in the kingdom Eubacteria are often classified according to their modes
of respiration and nutrition. In terms of respiration they are classified based on
whether or not they use oxygen. In terms of nutrition they are classified based
on how they obtain energy (autotrophs or heterotrophs).
8. Obligate aerobes are bacteria that respire in the presence of oxygen. Obligate
anaerobes grow and respire in the absence of oxygen and can be found in deep
soils, and marine and fresh water sediments.
9. A facultative aerobe is a bacterium that can perform respiration either with or
without oxygen. This advantage allows them to adjust to a variety of
environments.
10. During fermentation bacteria produce carbon dioxide and alcohol. Some groups
of bacteria will also produce ethyl alcohol, lactic acid, acetone, and acetic acid.
11. Heterotrophic bacteria obtain their nutrients from other organisms and are often
grouped as parasites or saprophytes. Parasitic bacteria obtain nutrients from a
host and do not contribute to the health of the host. In other words, parasitic
bacteria feed off of their host often causing damage. Many parasitic bacteria are
also pathogenic. Saprophytic bacteria obtain their nutrients from dead and
decaying organic matter and play a vital role in recycling organic matter. They
can be used in the treatment of sewage.
12. Autotrophic bacteria produce their own food using either energy from the sun or
energy from chemical reactions. Photosynthetic bacteria use energy from the
sun to convert inorganic (carbon dioxide and water) materials into organic
materials (glucose). Chemosynthetic bacteria perform the same conversion but it
is driven by energy that is trapped during the breakdown of chemicals.
13. Binary fission is asexual reproduction in bacteria. The single strand of bacterial
DNA replicates (copies) and the result is a copy for each new cell. After the
replication a cross wall begins to form and divides the bacterium into two
separate bacteria. They may separate or remain
attached.
14. Although sexual reproduction (combination of gametes) does not occur often in
bacteria, conjugation can occur in some intestinal bacteria such as E.coli. A
donor bacterium and a recipient bacterium make cell-to-cell contact and a
cytoplasmic bridge forms between the two cells. Pieces of DNA known as
plasmids can be transferred from the donor to the recipient. A change has now
been made in the set of characteristics (DNA) for the recipient. The two bacteria
will separate once the exchange has occurred.
15. Some bacillus type bacteria have been able to survive very harsh conditions
because of its ability to form an endospore. A thick wall will form around the
genetic material and a small amount of cytoplasm. The rest of the cell
disintegrates and the heat resistant endospore remains dormant until conditions
become favorable again.
16. The following are benefits of bacteria:
Type of Bacteria
Clostridia
Acetobacter
Intestinal bacteria
Lactobacilli
Aztobacter, nitrobacter
Streptococci, lactobacilli
Streptomyces
Beneficial Effects
Production of butanol and acetone from molasses
Production of vinegar from alcohol
Food digestion; synthesizing of vitamins in human
Production of lactic acid from sugar
Fixation of nitrogen in soils
Production of dairy products (cheese, yogurt)
Source of antibiotics (streptomycin and
erythromycin)
17. The bacteria dismantle complex toxic penta molecules, leaving nontoxic carbon
dioxide, water and harmless chlorides & they work cheaply requiring only oxygen &
nutrients normally found in the soil. They are also much cheaper to use and once the
toxic chemical is gone, they die.
18. Three types of bacteria are used to eliminate three components of gasoline so they
can be used to help clean up gasoline spills.
19. Antibiotic resistance develops from variations within a bacterial population. When
first exposed, the weaker strains of bacteria are killed. Others with slight variations in
their genetic material may allow them to survive the antibiotic. These bacteria then
survive and pass their resistance on to the next generation.