8/14/2019 BioD exp 2 & 3
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EXPERIMENT 2 : EUBACTERIA
EubacteriaEubacteria are prokaryotes that include most bacteria
and cyanobacteria.
Autotroph
Autotroph is an organism that is capable of synthesizing its own
organic substances frominorganic compounds, i.e., carbon dioxide.
Organisms that use light energy to synthesizeorganic compounds are
called photoautotrophs, i.e., cyanobacteria.
HeterotrophHeterotroph is an organism that requires organic
substrates, such as glucose , as energy sourcefor growth and
development. All animals are heterotrophic. Fungi and many bacteria
that lack chloroplast are also heterotrophic.
CyanobacteriaCyanobacteria, or blue-green algae, are one of the
largest and most important eubacteria. Theyare aquatic and
photosynthetic, serving as primary producers in many areas of the
ocean.For example, Oscillatoria sp., which is a filamentous
cynobacteria, can be found in a diverserange of conditions, in
stagnant water, damp soil, freshwater, and sea.
The Shapes of BacteriaCoccus1. Cocci are microorganisms with
spherical shapes.2. They occur in several basic forms:(i) coccus
(single) (iii) Streptococcus (bead-like chain)(ii) Diplococcus
(pair) (iv) Staphlylococcus (grape-like cluster)3. An example is
Staphlylococcus aureus , which causes a wide range of diseases from
minor skin infections to pneumonia.
Bacillus1. Bacilli are rod-shaped bacteria.2. An example is
Bacillus subtilis , which is a model organism.3. A model organism
is a species that has been studied extensively and often its entire
genomehas been sequenced.
Spirillum1. Spiral-shaped bacteria of the family Spirillaceae
are classified under the genus Spirillum.
2. An example is Spirillum minus , which causes rat-bite fever
in human.3. Rat-bite fever is caused by bacteria that pass from
rodent to human via the rodent's urine or mucous secretions. Its
symptoms include inflammation of the site of bite, recurring
fever,headache, and muscle ache. It is often treated with
antibiotic penicillin or tetracyclines.
Gram Stain ingThe Gram staining technique is used to group
bacteria on the basis of their forms, sizes, andGram reactions.
Gram staining permits the separation of all bacteria into two large
groups:Gram-positive and Gram-negative. Gram-positive bacteria
(e.g., Streptococcus spp.) have athick peptidoglygan wall outside
the cell membrane and retain the primary dye, that is,
crystalviolet, in the staining procedure. This is because
decolorizing the cell with alcohol causes the
thick peptidoglycan wall to dehydrate and to shrink, hence
closing the pores in the cell walland preventing the primary stain
from exiting the cell. In contrast, Gram-negative bacteria
http://en.wikipedia.org/wiki/Organic_compoundhttp://www.bio-medicine.org/Biology-Dictionary/glucose/http://en.wikipedia.org/wiki/Animalhttp://en.wikipedia.org/wiki/Fungihttp://en.wikipedia.org/wiki/Bacteriumhttp://en.wikipedia.org/wiki/Organic_compoundhttp://www.bio-medicine.org/Biology-Dictionary/glucose/http://en.wikipedia.org/wiki/Animalhttp://en.wikipedia.org/wiki/Fungihttp://en.wikipedia.org/wiki/Bacterium
