Page 119 - Biology_F5
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Biology for Advanced Level Secondary Schools
photosynthesis and supply it to fungi, (b) In farm animals, some diseases such as
while fungi provide support and protection anthrax in cattle, avian tuberculosis in
from dehydration to cyanobacteria. Some poultry, and black leg in sheep, goat and
non-pathogenic bacteria live on human cattle are caused by bacteria including
skin and are important in destroying Bacillus anthracis, Mycobacterium
harmful or pathogenic bacteria that live avium, and Clostridium chauvoel,
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in symbiotic association with human. respectively.
For example, Staphylococcus is among
skin microbiota (skin flora) that live (c) Some bacteria cause diseases in
symbiotically with human skin, protecting plants, resulting into crop destruction.
the host from pathogenic bacteria. In For example, corky root in lettuce,
addition, Ruminococcus bacteria that halo blight in beans, and bacterial
live symbiotically with ruminants, pith necrosis in tomatoes are
breakdown the plant fibres (cellulose) into caused by bacteria Rhizomonas
monosaccharides, and E.coli in human suberifaciens, Pseudomonas syringae
intestines synthesises vitamin K. pv. phaseolicola, and Pseudomonas
corrugata, respectively.
m) Biological control (d) Foods with high protein content are
Bacteria are potentially used in several often decomposed by bacteria, leading
biological control methods in agriculture to food spoilage. For example, the
and public health programs as bio smell coming from rotten eggs or any
pesticides. For example, some bacteria are other protein-containing foods results
soil dwelling Gram-positive, commonly from decomposition of protein by
used as biological pesticides. They proteolytic bacteria.
infect and kill the destructive organisms,
including caterpillar of some butterflies (e) During the process of bioleaching,
and larvae of some insects. An example of some bacteria, such as Thiobacillus
a soil dwelling Gram-positive bacterium oxidise sulphides to form sulphuric
+
is Bacillus thuringiensis. acid and hydrogen ions (H ), which
can leak into the ground and turn
Disadvantages of monerans surface and ground water into acidic
(a) Pathogenic bacteria cause diseases in water, hence water pollution.
humans. For instance; Vibrio cholerae (f) Bacteria called Clostridium botulinum
cause cholera, Treponema pallidum can release toxin into imperfectly
causes syphilis, Shigella dysenteriae canned foods.
cause shigellosis, Salmonella typhi cause
typhoid fever, Entamoeba histolytica cause
dysentery, Mycobacterium tuberculosis
causes tuberculosis, and Escherichia coli
causes Urinary Tract Infection (UTI).
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