Find the best tutors and institutes for Class 12 Tuition
Q10:
Microbes can be used to decrease the use of chemical fertilisers and pesticides. Explain how this can be accomplished.
Solution :
1. The Theoretical Framework: Biofertilizers and Biopesticides
The transition from synthetic chemical agriculture to sustainable, microbe-mediated agriculture relies on the application of Biofertilizers (organisms that enrich the nutrient quality of soil) and Biopesticides (organisms or biological derivatives that manage pests). This methodology circumvents the environmental degradation caused by chemical runoff, such as eutrophication and biomagnification [Per Principles of Sustainable Ecology].
2. Mechanism of Biofertilizers: Nutrient Augmentation
Biofertilizers function primarily through nitrogen fixation, phosphorus solubilization, and the synthesis of growth-promoting substances.
- Nitrogen Fixation: Bacteria like Rhizobium establish symbiotic relationships with leguminous plants, converting atmospheric $N_2$ into ammonia ($NH_3$) via the nitrogenase enzyme complex. Free-living bacteria like Azospirillum and Azotobacter also contribute by fixing nitrogen in the rhizosphere.
- Phosphorus Solubilization: Many soil microbes, such as Bacillus megaterium, produce organic acids that solubilize rock phosphate, making $PO_4^{3-}$ ions bioavailable for plant uptake.
- Mycorrhiza: Fungi, specifically of the genus Glomus, form symbiotic associations with roots, extending the root surface area for efficient absorption of phosphorus and water, while providing resistance to soil-borne pathogens.
3. Mechanism of Biopesticides: Biological Control
Biological control leverages the natural predator-prey or parasite-host dynamics to reduce the population of harmful agricultural pests without the toxicity associated with synthetic pesticides.
| Agent Type | Organism | Mechanism of Action |
|---|---|---|
| Bacterial | Bacillus thuringiensis | Produces crystal (cry) proteins that are toxic to specific insect larvae upon ingestion, causing gut paralysis. |
| Fungal | Trichoderma | Free-living fungi that act as biocontrol agents for several plant pathogens through hyperparasitism and competition. |
| Baculovirus | Nucleopolyhedrovirus | Genus Baculovirus; highly species-specific, narrow-spectrum insecticidal agents with no negative impact on non-target organisms. |
4. Visualizing the Microbial Rhizosphere Integration
5. Analytical Conclusion
By integrating these microbial agents, agricultural systems achieve a "Circular Nutrient Economy." Rhizobium and other fixers replace synthetic urea ($CO(NH_2)_2$), while Bacillus thuringiensis (Bt) provides targeted insect resistance, eliminating the need for organophosphate pesticides. This shift preserves the soil microbiome diversity and prevents the chemical pollution of groundwater aquifers [Per The Biological Control Act].
Final Solution: The application of microbes as biofertilizers (e.g., Rhizobium, Glomus) reduces dependency on chemical nitrogen/phosphorus fertilizers by enhancing nutrient bioavailability, while biopesticides (e.g., Bacillus thuringiensis, Baculoviruses) provide species-specific pest control, thereby eliminating the toxicity and environmental damage associated with synthetic chemical pesticides.
More Questions from Class 12 Biology Microbes in Human Welfare EXERCISES
- Q1: Bacteria cannot be seen with the naked eyes, but these can be seen with the help of a microscope. If you have to carry a sample from your home to your biology laboratory to demonstrate the presence of microbes with the help of a microscope, which sample would you carry and why?
- Q1: Bacteria cannot be seen with the naked eyes, but these can be seen with the help of a microscope. If you have to carry a sample from your home to your biology laboratory to demonstrate the presence of microbes with the help of a microscope, which sample would you carry and why?
- Q2: Give examples to prove that microbes release gases during metabolism.
- Q2: Give examples to prove that microbes release gases during metabolism.
- Q3: In which food would you find lactic acid bacteria? Mention some of their useful applications.
- Q3: In which food would you find lactic acid bacteria? Mention some of their useful applications.
- Q4: Name some traditional Indian foods made of wheat, rice and Bengal gram (or their products) which involve use of microbes.
- Q4: Name some traditional Indian foods made of wheat, rice and Bengal gram (or their products) which involve use of microbes.
- Q5: In which way have microbes played a major role in controlling diseases caused by harmful bacteria?
- Q5: In which way have microbes played a major role in controlling diseases caused by harmful bacteria?
- Q6: Name any two species of fungus, which are used in the production of the antibiotics.
- Q6: Name any two species of fungus, which are used in the production of the antibiotics.
- Q7: What is sewage? In which way can sewage be harmful to us?
- Q7: What is sewage? In which way can sewage be harmful to us?
- Q8: What is the key difference between primary and secondary sewage treatment?
- Q8: What is the key difference between primary and secondary sewage treatment?
- Q9: Do you think microbes can also be used as source of energy? If yes, how?
- Q9: Do you think microbes can also be used as source of energy? If yes, how?
- Q10: Microbes can be used to decrease the use of chemical fertilisers and pesticides. Explain how this can be accomplished.
- Q11: Three water samples namely river water, untreated sewage water and secondary effluent discharged from a sewage treatment plant were subjected to BOD test. The samples were labelled \(A\), \(B\) and \(C\); but the laboratory attendant did not note which was which. The BOD values of the three samples \(A\), \(B\) and \(C\) were recorded as 20mg/L, 8mg/L and 400mg/L, respectively. Which sample of the water is most polluted? Can you assign the correct label to each assuming the river water is relatively clean?
- Q11: Three water samples namely river water, untreated sewage water and secondary effluent discharged from a sewage treatment plant were subjected to BOD test. The samples were labelled (A), (B) and (C); but the laboratory attendant did not note which was which. The BOD values of the three samples (A), (B) and (C) were recorded as (20mg/L), (8mg/L) and (400mg/L), respectively. Which sample of the water is most polluted? Can you assign the correct label to each assuming the river water is relatively clean?
- Q12: Find out the name of the microbes from which Cyclosporin \(A\) (an immunosuppressive drug) and Statins (blood cholesterol lowering agents) are obtained.
- Q12: Find out the name of the microbes from which Cyclosporin (A) (an immunosuppressive drug) and Statins (blood cholesterol lowering agents) are obtained.
- Q13(a): Find out the role of microbes in the following and discuss it with your teacher. (a) Single cell protein (SCP)
- Q13(a): Find out the role of microbes in the following and discuss it with your teacher. (a) Single cell protein (SCP)
- Q13(b): Find out the role of microbes in the following and discuss it with your teacher. (b) Soil
- Q13(b): Find out the role of microbes in the following and discuss it with your teacher. (b) Soil
- Q14: Arrange the following in the decreasing order (most important first) of their importance, for the welfare of human society. Give reasons for your answer. Biogas, Citric acid, Penicillin and Curd
- Q14: Arrange the following in the decreasing order (most important first) of their importance, for the welfare of human society. Give reasons for your answer. Biogas, Citric acid, Penicillin and Curd
- Q15: How do biofertilisers enrich the fertility of the soil?
- Q15: How do biofertilisers enrich the fertility of the soil?
CBSE Solutions for Class 12 Biology Microbes in Human Welfare
Chapters in CBSE - Class 12 Biology
- Reproduction in Organisms
- Human Reproduction
- Reproductive Health
- Principles of Inheritance and Variation
- Molecular Basis of Inheritance
- Evolution
- Human Health and Disease
- Strategies for Enhancement in Food Production
- Biotechnology: Principles and Processes
- Biotechnology and Its Applications
- Organisms and Populations
- Ecosystem
- Biodiversity and Conservation
- Environmental Issues
Top Tutors who teach Microbes in Human Welfare
Super Tutor
Sector 59 E Block, Noida
6 yrs of
Exp
104 students
4770 hrs of classes completed
300
per hour
Online Classes
In my role as a teacher for Class 12, I've had the privilege of fostering a dynamic and engaging learning environment. Utilizing a combination of traditional teaching methods and modern technology, I've been able to ensure that students remain both interested and challenged. I've consistently strived to create a classroom atmosphere that promotes curiosity and encourages students to ask questions, facilitating a deeper understanding of the subject matter. As a Class 12th mentor, my goal has been to equip students not only with academic knowledge but also with the skills necessary for their future endeavors.
Very good teacher, the explanation was nice, i was able to understand all the little concepts that too in a short span of time.
Top Tutor
Banaswadi, Bangalore
5 yrs of
Exp
6 students
157 hrs of classes completed
400
per hour
Online Classes
I did MSc on Organic chemistry and qualified APSET and i have experience in teaching from 9th to 12th class students. and i am teaching effective, simple and understandable manner.
Alamganj, Patna
10 yrs of
Exp
Online Classes
I am an experienced English language and literature faculty. I completed my masters in MA from Patna University in the year 2016 and currently pursuing a PhD in English Literature. I am working as a Speaking Examiner with Cambridge Assessment English, UK. I have 10 years of experience in teaching Spoken English, BCom, BCA, BSc, BTech and Class X-XII selected subjects for ISC/ICSE, State and CBSE Board students. I have taught students of different age groups and demography. My classes are interactive and learner-oriented. I follow various aspects of training with special Emphasis on Pronunciation.
Top Tutor
HSR Layout 1st Sector, Bangalore
11 yrs of
Exp
25 students
2027 hrs of classes completed
400
per hour
Student's Home
I am a B.TECH. graduate from computer science.I am completely dedicated in teaching .I have experience of 10 years in teaching field. In that 10 years, I have taught 180 students(1 on 1)as a tutor.I have experience of teaching all types of boards like (CBSE,ICSE,IGCSE, ISC,STATE BOARD,IB) .My specialisation is in mathematics subject.I teach mathematics from 7th grade to 12th grade.I keep patience while teaching to the students,I try my best to clear the concepts regarding that chapter either in maths.Student can ask their doubts many times until their concepts is not clear.I have given good results to the students and also generated confidence in them specially in mathematics. I am the best for teaching maths subject. I first try to understand the student ( weakness and strength) and then I plan how to make any student best in math. I teach with full dedication and create interest for maths subject in my students. Thanks.
I wanted to express my gratitude for your exceptional guidance in math tuition. Your teaching style is not only informative but also engaging, making complex concepts seem much simpler. Your patience and willingness to go the extra mile to ensure I understand each topic are truly commendable. Thanks to your support, my confidence in math has soared, and my grades have improved significantly. Your dedication to your students' success is inspiring. I'm truly fortunate to have you as my math tutor, and I look forward to continuing to learn from you. Thank you for making math enjoyable!
Top Tutor
Karolan Ka Barh, Jaipur
10 yrs of
Exp
2 students
66 hrs of classes completed
700
per hour
Online Classes
Tutor's home
With 12 years of dedicated teaching experience, I have consistently aimed to deliver high-quality education in the field of Commerce and related subjects. Holding a B.Com, M.Com, and B.Ed, along with being UGC NET qualified, I have taught at various academic levels, ensuring conceptual clarity and practical understanding for students. My teaching approach emphasizes student engagement, real-life applications of theoretical knowledge, and consistent academic growth. I have successfully prepared students for board exams and competitive assessments, fostering both academic excellence and confidence. Throughout my career, I have remained committed to continuous learning and adapting to modern teaching methodologies.
Make complex topics easy to grasp and encourage the students and help in learning with such patient.
