8
Useful and Harmful Microbes
IMPORTANT POINTS:
The organisms which cannot be seen with our naked eyes, are called microbes. They seen with the help of microscope. Many microbes are prokaryotes. ▸ Some microbes are useful for us while some are harmful. Some of the useful microbes are (i) Lactobacilli - These are rod shaped bacteria. The anaerobic i.e. they do not require oxygen for their respiration. They convert milk into yoghur (ii) Rhizobium - These are symbiotic bacteria and are found in the root nodules of leg plants. They do the nitrogen fixation. (ii) Yeast - It is unicellular and eukaryote. Yeast is the process of fermentation process. e.g. in making of bread as well as alcohol. Yeasts repo by the process of budding. ▸ Antibiotics - These are the carbon compounds obtained from some bacteria and fung destroy or prevent the growth of harmful micro-organisms. ▸ The antibiotics which destroy only specific bacteria are called narrow-spectrum antibiotic those which destroy a wide variety of bacteria are called broad-spectrum antibiotics.
SPECIMEN QUESTIONS
(1) Yeast reproduces by the method of
(1) Cell division
(2) Spore formation
(3) Budding
(4) Fragmentation
Explanation: Yeast reproduces by budding. Option 3 is correct.
(2) Leguminous plants produce more proteins because of the presence of
(1) Lactobacilli
(2) Chlorophyll
(3) Rhizobium
(4) Clostridium
Explanation: The nodules on the roots of leguminous plants have bacteria Rhizobium in them. They do the nitrogen fixation i.e. convert the nitrogen from the atmosphere into nitrogen compounds. These nitrogen compounds are used in the production of proteins.
Option 3 is correct.
QUESTIONS FOR PRACTICE
(1)The poisonous chemicals released by fung are called___
(1) alcohols
(2) mycotoxins
(3) hormones
(4) antibiotics
Answers-(2) mycotoxin
________________________
(2)In butter milk-______ are present.
(1) Lactobacilli
(2) Mycobacterium
(3) Clostridium
(4) Penicillium
Answers-(1) Lactobacilli
_________________________
(3)the formation of yoghurt from milk, the - of proteins takes place.
(1) decomposition
(2) reduction
(3) oxidation
(4) coagulation
Answers-(4) coagulation
__________________________
(4)Penicillin is obtained from
(1) Staphylococci
(2) Clostridia
(3) Penicillium
(4) Streptococci
Answers-(3) Penicillium
__________________________
(5)The cooked food is spoiled by bacteria-
(1) Bacillus
(2) Clostridium
(3) Typhus
(4) Escherichia coli
Answers- (2) Clostridium
___________________________
(6) In the production of___yeast is notrequired.
(1) bread
(2) beer
(3) yoghurt
(4) wine
Answers-(3) yoghurt
______________________
(7)In the fermentation process, - gas is produced.
(1) ammonia
(2) carbon dioxide
(3) oxygen
(4) nitrogen
Answers-(2) carbon dioxide
__________________________
(8) ___is a narrow spectrum antibiotic.
(1) ampicillin
(2) gentamycin
(3) amoxicillin
(4) tetracycline
Answers - (2) gentamycin
_________________________
(9) The patients of disease-should not go to the crowded places. of in
(1) arthritis
(2) swine flu
(3) cancer
(4) diabetes
Answers- (2) swine flu
______________________
(10) Yeast-absorbs the pollutant arsenic.
(1) Yarrowialipolytica
(2) Alcanivorax
(3) Saccharomyces cerevisiae
(4) Lactobacilli
Answers -(3) Saccharomyces cerevisiae
______________________
(11) There is no cure for disease
(1) Typhoid
(2) AIDS
(3) Tuberculosis
(4) Malaria
Answers - (2) AIDS
____________________
(12)__ is a disease caused by bacteria.
(1) Measles
(2) Hepatitis
(3) Swine flu
(4) Pneumonia
Answers -(4) Pneumonia
____________________
(13) is a broad spectrum antibiotic.
(1) Penicillin
(2) Gentamycin
(3) Erythromycin n re
(4) Tetracycline
Answers - (4) Tetracycline
_____________________
(14) Yeast is used to absorb the toxins released during the production of palm oil.
(1) Yarrowialipolytica
(2) Salmonella
(3) Mycobacterium
(4) Alcanivorax
Answers - (1) Yarrowialipolytica
_________________
(15) The disease is caused by protozoa.
(1) Cholera
(2) Measles
(3) AIDS
(4) Malaria
Answers -(4) Malaria
_____________
(16) is a viral disease.
(1) Leprosy
(2) Malaria
(3) Influenza
(4) Pneumonia
Answers- (3) Influenza
___________________
(17) Meat gets spoiled due to
(1) Clostridium botulinum
(2) Penicillium
(3) Lactobacilli
(4) Staphylococcus
Answers - (1) Clostridium botulinum
__________________
(18) Lactobacilli the pH of the milk.
(1) decreases
(2) increases
(3) do not affect
(4) doubles
Answers -(1) decreases
________________
(19) Find the odd man out.
(1) Pneumonia
(2) Leprosy
(3) Chicken pox
(4) Cholera
Answers - (3) Chicken pox
_______________
(20) Which of the following diseases is communicable?
(1) Arthritis
(2) Diabetes
(3) Cancer
(4) Pneumonia
Answers- (4) Pneumonia
________________
Hints for difficult questions)
19) Chicken pox is caused by virus, others are caused by bacteria.
..Option 3 is correct.
कोणत्याही टिप्पण्या नाहीत:
टिप्पणी पोस्ट करा