The Class 10 is an important year in a student’s life and Maharashtra State Board Science 2 is one of the subjects that require dedication, hard work, and practice. It’s a subject where you can score well if you are well-versed with the concepts, remember the important formulas and solving methods, and have done an ample amount of practice. Worry not! Home Revise is here to make your Class 10 journey even easier. It’s essential for students to have the right study material and notes to prepare for their board examinations, and through Home Revise, you can cover all the fundamental topics in the subject and the complete Maharashtra State Board Class 10 Science 2 Book syllabus.
1. Write about probiotics.
Answer: Milk products containing active bacteria, such as Lactobacillus, Acidophilus, Lactobacillus casei, Bifidobacterium bifidum and so on are probiotics. These microbes maintain the balance of intestinal microorganisms. That is, with the increase in the population of microbes helping the digestion, there is also a decrease in the population of harmful microbes (ex. Clostridium). Probiotic products are available as yoghurt, kefir, sauerkraut (pickle of cabbage), dark chocolate, miso soup, pickles, oils, corn syrup, artificial sweeteners, microalgae (Seafood like Spirulina, Chlorella, Blue green algae, etc.). These products produce the colonies of useful microbes in the alimentary canal and control other microbes and their metabolic activities, thus improving resistance and lowering the ill-effects of harmful substances that are generated during metabolic activities. Useful microbes that have become inactive due to antibiotics are made active again with the help of probiotics. Nowadays, probiotics are used for treatment of diarrhoea and treatment of poultry also.
2. Which fuels can be obtained by microbial processes? Why is it necessary to increase the use of such fuels?
Answer: Some of the gases obtained by microbial process are given below:
1. Ethanol is a byproduct formed during the fermentation process of molasses by Saccharomyces . It is a type of alcohol and a clean (smokeless) fuel mixed with petrol and diesel to prevent vehicular emission
2. Methane is a gaseous fuel that is obtained by microbial anaerobic decomposition of urban agricultural and industrial waste
3. Hydrogen fuel, released during bio-photolysis of water, in which bacteria perform photoreduction. It is considered as the fuel of the future as it is non-polluting and an efficient fuel
Fuels obtained from fossil fuels are nonrenewable and also polluting. Meanwhile, these fuels such as hydrogen, ethanol, and methane are the future fuels, because they burn cleaner with the same efficiency and are renewable
3. Explain cheese production.
Answer: Cheese is produced abundantly worldwide on a large scale from cow’s milk. First step to it is to perform chemical and microbiological tests of milk and then add colours and microbes like Lactobacillus lactis, Lactobacillus cremoris, and Streptococcus thermophilus. This gives it a sour taste. Then to get the dense texture, the whey or water in the yoghurt is removed. For this, an enzyme, rennet that was obtained from the alimentary canal of cattle was being traditionally used earlier. However, currently, an enzyme protease obtained from fungi is used to manufacture vegetarian cheese. Whey, separated from yoghurt has some other uses. Then, the production of cheese is started through steps such as cutting the solid yoghurt into pieces, washing, rubbing, salting, and mixing of essential microbes, pigments and flavours. Then, cheese is pressed and cut into pieces and stored for ripening.
4. How is soya sauce produced?
Answer: Soya sauce is made by fermenting the mixture of flour of wheat or rice and soybean with the help of the fungus Aspergillus oryzae.
5. What is the xanthan gum that imparts thickness to your favourite ice creams, puddings, chocolates, milk shakes, chocolate drinks, instant soups, etc.?
Answer: This gum is obtained by fermenting starch and molasses with the help of Xanthomonas species. This gum has properties such as solubility in hot and cold water, high density and so on. It is also used for production of pigments, fertilizers, weedicides, textile pigments, toothpastes, high quality paper and more.
6. What are the uses of Citric, Malic and Lactic acid that are obtained by microbial processing?
Answer: Citric, Malic and Lactic acid are substances obtained by microbial processing. They are used for imparting acidity.
7. What are biofuels?
Answer: One of the important renewable source of good energy, biofuel is available in solid (coal, dung, crop residue), liquid (vegetable oils, alcohol) and gas (gobar gas, coal gas) forms. Easily available, these fuels can be found in plenty of quantity. Hence, these are reliable fuels of the future.
8. How are the sewage generated in cities or villages disposed off?
Answer: Domestic sewage, in villages is disposed off, either in nearby soil or in biogas plants. Alternatively, the sewage in cities needs to be carried to processing units and acted upon by microbial processes.
9. Explain sewage management.
Answer : Sewage is mixed with microbes that can decompose any compound as well as destroy the pathogens of cholera, typhoid and so on. Then, they generate methane and CO2 by decomposing the carbon compounds found in the sewage. Phenol oxidizing bacteria will also decompose the xenobiotic chemicals in sewage. Afterwards, the sludge that settles down in this process is again used as fertilizer. Water released following the microbial treatment is environmentally safe and the microbes are used for bioremediation of environment polluted due to sewage.
10. Name the bacteria used to remove oil spills. How is it done?
Answer: Petroleum oil may spill into the ocean because of several reasons and this may prove fatal and toxic to aquatic organisms. It is not that easy to remove the oil layer from the surface of water using mechanical methods. However, bacteria like Pseudomonas spp. and Alcanovorax borkumensis have the ability to destroy the pyridines and other chemicals. So, this bacteria called hydrocarbonoclastic bacteria (HCB) is used to clear the oil spills. HCB decomposes the hydrocarbons and causes the reaction of carbon with oxygen forming CO2 and water in this process.