Xam Idea Class 12 Biology Chapter 10 Solutions: Microbes In Human Welfare

Xam Idea Class 12 Biology Solutions Chapter 10 ‘Microbes in Human Welfare’ describes the role microbes play in our lives and how they are beneficial to us. They cannot be seen with naked eyes, some of the microbes are fungi, bacteria, etc. Our Xam Idea solutions explain how these microbes maintain the ecosystem balance and what are some of the good and bad microbes. You will also learn their various uses in industries, energy production, household, and sewage treatment. How microbes act like biofertilizers and biocontrol agents and their use in antibiotics production is also discussed in our Xam Idea Solutions for Class 12 Microbes in Human Welfare.

Xam Idea Class 12 Biology Solutions for Microbes in Human Welfare have a total of 143 questions divided into 8 sets. Xam idea explores the entire chapter fully so that you get maximum benefit by going through our solutions to them. The exercises include HOTS (Higher-order thinking) questions to stimulate high order thinking in you. There are short and long type questions, assertion-reason types, and MCQs. All the questions are based on the CBSE pattern so that you get a feel of how the question would be in your board exams or any competitive exams.

At Instasolv, we have a team of experts in every subject who do extensive research before formulating any solution for Xam Idea Class 12 Microbes in Human Welfare. That is why they cater to your needs of clarifying the root concepts apart from merely knowing how to solve the problems. By following our solutions a good grade is guaranteed in your CBSE Class 12 exams and you would also gain confidence for sitting in any medical or engineering competitive exams such as NEET.

Important Topics for Xam Idea Class 12 Biology Solutions Chapter 10: Microbes in Human Welfare

Microbes occupy every part around us, form air to water to soil and any other inhabitable place. They are diverse; fungi, Protozoa, bacteria, viroid, and also prions are all microbes. They can cause disease but at the same time be useful for humans. We will see some of their properties and varieties here:

Microbes – They are microscopic bodies which cannot be seen by naked eyes and pervade the air, soil, water, and also exist inside bodies of living organisms. They can survive even in extreme conditions like an acidic environment, under the snow, thermal vents, and deep inside soil.

Microbes in Household Products –

Curd – A microbe called Lactobacillus or LAB (Lacto acid bacteria) is present in the curd starter which multiples at a suitable temperature converting milk to curd. The milk protein, casein, is partially digested when acid is released by LAB during the processing of curdling. This helps in increasing the nutritional value of the milk.

Dough – Bread and dough used in making dosas and idlis are fermented by bacteria. A common bacteria used in this is Saccharomyces cerevisiae or baker’s yeast. The puffiness to food comes by the CO2 released by the bacteria.

Microbes in Industrial Purposes – Fermenters are used for large scale production of many compounds in industries. Some beverages and antibiotics need bacteria for their development.

Fermented beverages – Saccharomyces cerevisiae or brewer’s yeast is used to ferment malted cereals and fruit juices to produce ethanol. The type of alcoholic drink produced depends on the processing:

  • Wine and beer are produced without distillation
  • Brandy and rum are produced by distillation.

Antibiotics – They are used to kill or slow down the growth of harmful bacteria. Penicillin was the first antibiotic to be discovered by Fleming when he was working on Staphylococcus bacteria. Many diseases like diphtheria, plague, and whooping cough can be cured by antibiotics.

Microbes in Sewage Treatment – Sewage is huge quantities of water waste mainly having human excreta in it. They have a lot of pathogenic microbes and organic matter which needs to be made less polluting before eliminating them in large bodies of water. STP or sewage treatment plan is carried out for this activity. STP consists of 2 parts:

In part 1 debris and sediments are removed physically. First, sewage is passed through a mesh to remove floating debris and then kept in tankers so that grit; like soil and small pebbles form sediment. The sediment is the primary sludge and the supernatant is the effluent.

In part 2, the supernatant is passed through mechanical agitation and air supply in aeration tanks. This results in the rapid growth of aerobic bacteria called flocs which then consumes organic matter to reduce BOD (biological oxygen demand). This sludge is then passed through settling tanks and then large anaerobic sludge digesters where heterotrophic microbes digest the bacteria and fungi in the sludge along with the release of biogas which is a mixture of gases like H2S and CO2. After this, the effluent is released into rivers and streams.

BOD – Biological oxygen demand refers to the rate of oxygen uptake of organic matter in water. A higher BOD represents a high polluting material.

Microbes as Biocontrol Agents – Biocontrol is the process of controlling pests and plant disease by biological methods. Earlier insecticides and pesticides were used for this but they are chemical toxins that are harmful to humans and animals and they also pollute the environment. Organic farmers now use a holistic approach by keeping checks and balances so that pests are at a manageable level, rather than totally eradicating them. This is done by familiarizing themselves with the many life-forms inhabiting the field and about their pattern of feeding and life cycles. Some forms of Biocontrol include:

  • Bacillus thuringiens is a bacteria used to control butterfly caterpillars.
  • Ladybirds can get rid of aphids
  • Dragonflies can kill mosquitoes.
  • Trichoderma SPS are free-living fungi in the root ecosystem and act against many plant pathogens.

Discussion of Exercises of Xam Idea Class 12 Biology Solutions Chapter 10

  • There are 15 questions in the first set which are taken from the NCERT textbook. The questions touch topics like metabolism of microbes, useful applications of bacteria, use of bacteria in Indian food, etc. You must remember the names of some important bacteria and their functions to answer these questions.
  • The 2nd set has 20 multiple-choice questions. You have to apply your knowledge of how curd is made from bacteria, sewage treatment, bacteria and their commercial products, usage of bacteria in beverages; to answer these questions.
  • In the 3rd set, there is 1 assertion-reason type question. It has 10 statements for which the correct combination of assertion and reason has to be chosen. The topics in these cover Biogas, aerobic and anaerobic process, bacteria in curd, and sewage treatment.
  • The 4th set has 23 questions that need very short answers. Questions are based on types of viruses and bacteria, curd and its benefits, doughing method, names of microbes used in beverages, etc.
  • You have 43 questions in the 5th set which require short answers. You get to answer questions on LAB and curd formation method, names and application of microbes as a food supplement, antibiotics, and biocontrol agents.
  • In the 6th set, you need to give short answers to its 21 questions. Some of the highlights of the questions are:
  1. A table of organisms, bioactive elements and their uses are given with some parts unfilled. You need to fill in the blanks
  2. The sequence of events in a Biogas plant
  3. The functions of anaerobic sludge digester in STP
  • The 7th set has 8 questions which are long answer types. Few topics in this set are biofertilizers, the role of baculoviruses, baculoviruses, and Nucleopolyhedrovirus as biocontrol agents.
  • The 8th and last set is a self-assessment part with 12 questions. Questions are a mix of MCQs, assertion-reason, short and long answer types that brush your knowledge on the entire chapter.

Why Use Xam Idea Class 12 Biology Solutions Chapter 10: Microbes in Human Welfare by Instasolv?

  • Biology is an important subject for anyone who wants to get into the medical field or do well in CBSE board exams. 
  • Our Xam Idea solutions are meant to empower you with deep knowledge on this subject with clear and lucid explanations of every question. 
  • The solutions will act as a quick revision of the entire chapter and it is written in an easy to understand way so that you can quickly go through them. 
  • These solutions are free of cost and available online for ease of access anytime, anywhere.