Antibiotics produced by microbes are regarded as one of the most significant discoveries of the twentieth century. Antibiotics are the chemical substances which are produced by some microbes and can kill or retard the growth of other (diseasecausing) microbes.
(a) Name the scientist who discovered the first antibiotic and the organism he was working on.
(b) Name the first antibiotic and its source organism.
(c) Name the scientists who established the potential of the above as an effective antibiotic.

Rivers like Ganga, Cauvery, Yamuna, etc. are considered sacred rivers. Just because of this reason, the load of pollution in these rivers is increased as people throw into them many things in the name
of puja. Many factories also let their effluents into the rivers.
(a) What has the government done to check pollution in these rivers?
(b) What does the BOD test measure in the water bodies?

Cowdung and water is mixed and the slurry is fed into biogas plant for digestion by microbes. The person performing the process shares that there is no need to provide any inoculum to it.
(a) Give reason why no inoculum is needed.
(b) What is the role of the microbes at the source?
(c) Mention the condition under which they will be most active and effective.

Read the following and answer any four questions from (i) to (v) given below:
Microorganisms include bacteria, viruses, fungi and protozoa. In our mind, we presume, most of the time, that microbes are always harmful. Microbes are, of course, the causal agents of many infections diseases of plants and animals including humans but they also have lots of beneficial role. Lactic acid bacteria (LAB) are one of this kind of useful group. These are Gram positive, non-sporulating, either rod shaped or spherical bacteria. They produce lactic acid in milk products as major metabolic end product of carbohydrate fermentation. LAB are considered as natural fermentors. Lactobacillus is a common LAB which converts lactose sugar of milk into lactic acid, that causes coagulation and partial digestion of milk protein casein. Milk is then changed into curd, yoghurt and cheese. Lactobacillus is also used in probiotics which have potentially beneficial effect on gut ecosystem of humans. Some other pro biotic strain used belong to the Genus Bifidobacterium.
(i) Which of the following is not considered as microorganisms?

(ii) Select the incorrect option regarding the characteristics oflactic acid bacteria.

(iii) Which of the following is not a lactic acid producing bacteria?

(iv) Probiotics are

(v) Assertion: Lactobacillus bacteria do not retain crystal violet stain while staining.
Reason: Lactobacillus have a very thin layer of peptidoglycan layer in their cell wall.
(a) Both assertion and reason are true and reason is the correct explanation of assertion.
(b) Both assertion and reason are true but reason is not the correct explanation of assertion.
(c) Assertion is true but reason is false.
(d) Both assertion and reason are false.

Read the following and answer any four questions from (i) to (v) given below:
Alcohols are important industrial solvents. Ethanol, methanol, propanol and butanol are produced commercially by fermentation activity of some fungi, majorly yeasts. During fermentation, yeast cells convert cereal derived sugars into ethanol and CO₂. At the same time hundreds of secondary metabolites that influence the aroma and taste of alcohol are produced. Sugar concentration affects the rate of fermentation reactions. Yeast cannot grow in very strong sugar solution. In case of complex carbohydrate containing nutrient media, 1% malt or Rhizopus is used along with yeasts. Hydrolysis of starch is carried out at high temperature for 30 mins. The crushed food mixed with hot water for obtaining malt in called mash. The nutrient medium prior to fermentation in called wort. Wort is cooled down to appropriate temperature and inoculated with strain of yeast.
(i) The rate of alcohol production is measured on the basis of

(ii) A number of chemicals are produced at the time of alcoholic fermentation with the change of nutrient media, pH and aeration. Select such by-product from the following.

(iii) During alcoholic fermentation of cereals and potato, the crushed food mixed with hot water for obtaining malt is called

(iv) Distilled alcohol with 95% ethanol content is called

(v) Assertion: Rhizopus or 1% malt is used in the nutrient medium when it contains complex carbohydrates.
Reason: Yeast does not possess sufficient diastase or amylase.
(a) Both assertion and reason are true and reason is the correct explanation of assertion.
(b) Both assertion and reason are true but reason is not the correct explanation of assertion.
(c) Assertion is true but reason is false.
(d) Both assertion and reason are false.