May 25, 2013

Senior Inter Botany Important Questions and Answers

Short answer type questions (4 marks)

1. Explain the importance of Microbiology.
Importance of microbiology:
A large number of micro organisms are useful to man in many
ways.
Saprophytic bacteria and fungi cause decomposition of organic
wastes and help in the process of humification and mineralization
which are important to the nutrient cycles.
Many fungi and bacteria are used for production of antibiotics,
alcohols, enzymes and hormones on industrial scale.
Bacterial plasmids are used as tools in genetic engineering and bio
technology.
LAB is used for conversion of milk into curds. Bacteria are also
used in sewage treatment.
Some bacteria like Methano coccus and Methano bacillus are
useful in production of bio gas.
Bacteria are also used as bio control agents in pest and diseases
control in agriculture. Bacteria like Rhizobium, Azospirillum,
Azotobater are used as bio fertilizers.
Micro organisms like Nostoc and Anabaena are used as nitrogen
fixers in agriculture.
Microbes are presently used in bio-mining for extraction of metals
like uranium.
Bacterial DNA components are used as Biosensors to detect toxic
pollutants.
They are also used in medical diagnostics, food and fermentation
operations.
Bacteria are the real tools in genetic engineering.

2. How are bacteria classified on the basis of morphology?
Bacteria are classified into the following types based on the morphology and
shapes:
Cocci – spherical
Bacilli – Rod shaped
Spirillum – helical rods (more than one complete twist)
Vibrios – comma shaped (less than one complete twist)
Pleomorphic – bacteria change their shape depending on the type of
environment or available nutrients.
Spirochaets – flexible spiral bacteria (slender long an cork-screw
shaped)
Filamentous – long thread like or filament like chains
Bacteria cells may be single or in groups like
Monococcus – single spherical cell
Diplococcus – a pair of spherical cells
Tetra coccus – a group of four spherical cells
Streptococcus – linear chain of spherical cells
Staphylococcus – bunches of spherical cells
Sarcinae – eight spherical cells arranged as a cube
Monobacillus – single rod shaped cell
Diplobacillus – a pair of rod shaped cells
Streptobacillus – chains of bacilli appearing like straws

3. How are bacteria classified on the basis of number and distribution of
flagella?
Based on the number and distribution of flagella bacteria may be classified
into the following types:
Monotrichous – bacterium with a single polar flagellum
Amphitrichous –bacterium with single flagellum at each end
Lophotrichous – bacterium two or more flagella at one pole
Peritrichous – bacterium with flagella distributed all over the cell.

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