(a) (i) List two diseases each of plants and animals caused by bacteria.
(ii) State three ways in which bacteria are useful.
(b) State three methods by which mosquitoes can be controlled and state the reason for each method
(c) Describe an experiment to demostrate the presence of bacteria under the finger nails
Explanation
(a)(i) Diseases of plants caused by bacteria are:
(i) Soft roots
(ii) fire blight, wilts, crown gall. Disease of animals caused by bacteria are tuberculosis, cholera, leprosy , gonorrhoea, syphilis, diptheria, tetanus
(ii) Ways in which bacteria are useful are:
(1) Some bacteria are used in the preparation of cheese, butter and vinegar.
(2) Some are used in the production of antibiotics, enzymes, vitamins and amino acids for commercial purposes.
(3) In leguminous plants, bacteria such as Rhizobium found in the root nodules convert atmospheric nitrogen to soil nitrogen thus enhancing the nitrogen content of the soil.
(4) Some bacteria help in the digestion of cellulose
(5) Some bacteria help in the fermentation of alcohol and beverages.
(6) Certain bacteria known as sewage bacteria assist in the decomposition of sewage into harmless substances that could be used as manure.
(b) Mosquitoes can be controlled in the following ways:
(1) Bush around the surrounding should be cleared to prevent breeding grounds for mosquitoes.
(2) Mosquito net should be provided or fitted to our windows to prevent mosquitoes from coming within to suck human blood.
(3) Apply insecticides to kill mosquito or pour kerosine or oil on stagnant water around the house to prevent breeding.
(c) Aim: To show the presence of bacteria under the finger nails.
Apparatus: Incubator, innoculating loop, nail cutter, petridish, blood agar, microscope and cover slip.
Procedure: Cut the finger nails and place them in a petridish which have the blood agar. Then incubate at 37°C for two days.
Observation: It was discovered that colonies of bacteria were growing on the blood agar. On gram staining, one saw clusters of cocci bacteria. Conclusion: The growth of cocci bacteria indicates that bacteria grow on finger nails.