A chemical substance produced by certain microorganisms that kills or inhibits the growth of disease-causing microorganisms is called an antibiotic.
Definitions [5]
Define the following term
Zymology
Zymology is an applied science which deals with the biochemical process of fermentation and its practical uses.
Define the following term
Antibiotics
Antibiotics are chemical substances produced by microorganisms which can kill or retard the growth of other disease causing microbes even in low concentration. Antibiotic means “against life”.
Define the following terms
Superbug
"Superbug" is a term used to describe strains of bacteria that are resistant to the majority of antibiotics commonly used today.
Define bioherbicides.
Bioherbicides are living creatures such as microbes, fungi, insects, or other pathogens that are employed to restrict the population of undesired plants in agricultural fields, ponds, lakes, and so on.
Definition: Antibiotic
Key Points
Key Points: Microbes in Household Products
| Product | Micro-organisms Used | Function |
|---|---|---|
| Curd | Lactobacillus (LAB) | Converts milk into curd, increases vitamin B₁₂ |
| Butter | Streptococcus cremoris, Leuconostoc dextranicum | Gives flavour and aroma |
| Yogurt | Lactobacillus bulgaricus, Streptococcus thermophilus | Ferments milk at 40°C |
| Cheese | Streptococcus lactis, Leuconostoc, fungi | Curdling and ripening of cheese |
| Swiss Cheese | Propionibacterium shermanii | Produces CO₂, forms holes |
| Roquefort Cheese | Penicillium roqueforti | Ripening and flavour |
| Camembert Cheese | Penicillium camemberti | Soft texture and taste |
Key Points: Microbes in Industries
- Micro-organisms are ideal for industries due to their fast growth, high metabolic activity, and enzyme diversity.
- They are grown in large vessels called fermenters for large-scale production.
- Microbes are used to produce medicines like steroids, vaccines, human insulin, and immunosuppressive drugs.
- Many important antibiotics such as penicillin, streptomycin, tetracycline, and erythromycin are obtained from microbes.
- Microbial fermentation is used to produce vitamins (B₁₂, riboflavin) and human proteins using recombinant DNA technology.
- Several organic acids (citric, lactic, acetic) and amino acids (lysine, glutamic acid) are industrially produced by microbes.
- Microbes produce enzymes used in detergents, food processing, textiles, medicines, and plastic industries.
- Yeasts are widely used for producing ethanol and fermented beverages like beer, wine, whisky, and rum.
Key Points: Types of Biocontrol Agents
| Category | Biocontrol Agent | Target / Use |
|---|---|---|
| Insects | Ladybird beetle | Controls aphids |
| Insects | Dragonfly | Controls mosquitoes |
| Viruses | Baculoviruses (NPV) | Control insect pests like bollworm |
| Bacteria | Bacillus thuringiensis | Controls insect pests and mosquito larvae |
| Bacteria | Agrobacterium radiobacter (K-84) | Controls crown gall disease |
| Bacteria | Pseudomonas sp. | Controls fungal disease (damping off) |
| Fungi | Trichoderma sp. | Controls many plant diseases |
| Fungi | Beauveria, Metarhizium, Verticillium | Control insect pests |
| Fungi | Aschersonia aleyrodis | Controls whiteflies |
Key Points: Microbes as Biofertilizers
- Biofertilizers are living micro-organisms that improve soil fertility by increasing the availability of nutrients to plants.
- They are eco-friendly alternatives to chemical fertilizers, which degrade soil quality and reduce microbial life.
- Nitrogen-fixing microbes such as Rhizobium, Azotobacter, Azospirillum, and Frankia convert atmospheric nitrogen into usable forms.
- Legume–Rhizobium symbiosis forms root nodules that fix large amounts of nitrogen and enrich the soil for subsequent crops.
- Azolla–Anabaena symbiosis and cyanobacteria are widely used in paddy fields and significantly increase rice yield.
- Mycorrhiza (fungus–root association) enhances absorption of phosphorus and other minerals and protects plants from pathogens.
- Phosphate-solubilizing bacteria and fungi convert insoluble phosphates into forms available to plants.
- Biofertilizers improve crop yield, reduce fertilizer requirement, and help in sustainable agriculture and soil conservation.
Key Points: Microbes in Production of Biogas
- Biogas is a fuel gas rich in methane, produced by anaerobic microbial activity on organic waste.
- Methanogens (e.g., Methanobacterium) anaerobically digest cellulosic material and produce methane, CO₂ and H₂.
- These microbes occur naturally in sewage sludge and in the rumen of cattle, aiding cellulose digestion; cattle dung is therefore used for biogas production.
- Biogas plants use dung slurry in anaerobic tanks to generate gas for cooking and lighting, while the leftover slurry serves as a good fertiliser.
Key Points: Microbes in Sewage Treatment
| Stage / Aspect | Process Involved | Role of Microbes | Result |
|---|---|---|---|
| Sewage | Municipal wastewater containing organic matter and pathogens | Naturally present microbes | Highly polluting if untreated |
| Primary Treatment | Physical removal by filtration and sedimentation | No active microbial role | Removes debris and forms primary sludge |
| Secondary Treatment | Aeration to promote microbial growth | Aerobic bacteria and fungi form flocs | Reduces BOD significantly |
| Activated Sludge | Settling of microbial flocs | Bacteria reused or digested | Part recycled, part sent to digesters |
| Anaerobic Digestion | Sludge broken down in digesters | Anaerobic bacteria | Produces biogas and treated effluent |
Important Questions [60]
- Name the Group of Bacteria Involved in Setting Milk into Curd. Explain the Process They Carry in Doing So. Write Another Beneficial Role of Such Bacteria.
- Name the Microbes that Help the Production of the Following Product Commercially: Citric Acid
- Answer the Following Question: Why Does 'Swiss Cheese' Develop Large Holes?
- Name the source of streptokinase. How does this bioreactor molecule function in our body?
- Name the Microbes that Help the Production of the Following Product Commercially: Statin
- Given below are the list of the commercially important products and their source organisms. Select the option that gives the correct matches. List A List B S No. Bioactive Products
- Answer the following question based on Meselson and Stahl's experiment on E. coli : Write the name of the chemical substance used as the only source of nitrogen in the experiment.
- State the most important contribution of the following microbes for human welfare: Monascus purpureus
- State the medicinal value and the bioactive molecules produced by Trichoderma polysporum.
- State the medicinal value and the bioactive molecules produced by Monascus purpureus.
- State the medicinal value and the bioactive molecules produced by Penicillium notatum, Monascus purpureus and Trichoderma polysporum.
- Why are the fruit juices bought from market clearer as compared to those made at home?
- Name the Microbes that Help the Production of the Following Product Commercially: Penicillin
- State the most important contribution of the following microbes for human welfare: Trichoderma Polysporum
- Name the drug a patient who has undergone a successful organ transplant, has to take all his/her life.
- Distinguish Between the Roles of Flocs and Anaerobic Sludge Digesters in Sewage Treatments.
- Explain the Process of Secondary Treatment Given to the Primary Effluent up to the Point It Shows Significant Change in the Level of Biological Oxygen Demand (Bod) It
- Study the given diagram of the Sewage treatment Plant (S.T.P.) and answer the question that follows:
- What are flocs with respect to sewage treatment?
- Explain the Function of “Anaerobic Sludge Digester” in a Sewage Treatment Plant.
- Explain the Different Steps Involved During Primary Treatment Phase of Sewage.
- Answer the Following Question. What Are 'Flocs', Formed During Secondary Treatment of Sewage?
- Explain the process of sewage water treatment before it can be discharged into natural water bodies.
- Describe how do 'flocs' and 'activated sludge' help in Sewage Treatment.
- Answer the Following Question. Secondary Treatment of the Sewage is Also Called Biological Treatment. Justify this Statement and Explain the Process.
- Answer the Following Question. What Are ‘Flocs’, Formed During Secondary Treatment of Sewage?
- How Do Methanogens Help to Generate Biogas?
- What Are Methanogens?
- Name the Animals in Which Methanogens Occur and the Role They Play There.
- Answer the Following Question. Write Any Two Places Where Methanogens Can Be Found.
- Answer the Following Question. Write Any Two Places Where Methanogens Can Be Found.
- Can we use slurry of human excreta instead of cowdung slurry to produce biogas in a typical biogas plant? Support your answer giving reasons.
- How do organic farmers control pests? Give two examples.
- Name the Bioactive Molecules Produced by Trichoderma Polysporum and Monascus Purpureus.
- State the Medicinal Value and the Bioactive Molecules Produced by Streptococcus, Monascus and Trichoderma.
- Name and explain the type of interaction that exists in mycorrhizae and between cattle egret and cattle.
- Many members of genus Glomus form a mycorrhizal association with plants. Elaborate how is this association beneficial to the plants.
- Organic farmer use Trichoderma as biological control agents. Explain.
- Organic farmer use Baculovirus as biological control agents. Explain.
- Give an example of a bacterium, a fungus and an insect that are used as biocontrol agents.
- Organic Farmers Prefer the Biological Control of Diseases and Pests to the Use of Chemicals for the Same Purpose. Justify
- State the difference in organic farmers approach from that of conventional pest control methods.
- Give an example of a genus of virus used as narrow spectrum insecticidal biocontrol agent. How does its use serve as an aid in overall integrated pest management programme?
- How Does the Activity of Each One of the Following Help in Organic Farming? Mycorrhiza
- Name a genus of baculovirus.
- Name a genus of fungi that forms a mycorrhizal association with plants.
- Why are baculoviruses considered good biocontrol agents?
- Explain the significant role of the genus Nucleopolyhedrovirus in an ecological sensitive area.
- Name the type of association that the genus Glomus exhibits with higher plants.
- Mention One Advantage and One Disadvantage to a Farmer Who Uses Them.
- Given below is a list of six micro-organisms. State their usefulness to humans. (a) Nucleopolyhedrovirus (b) Saccharomyces cerevisiae (c) Monascus purpureus (d) Trichoderma polysporum
- How Do Mycorrhizae Act as Biofertilizers? Explain.
- Your Advice is Sought to Improve the Nitrogen Content of the Soil to Be Used for Cultivation of a Non-leguminous Terrestrial Crop. (a) Recommend Two Microbes that Can Enrich the Soil with Nitrogen.
- How does the application of cyanobacteria help improve agricultural output?
- How does the application of the fungal genus, Glomus, to the agricultural farm increase the farm output?
- Give an example of a genus of fungi that forms mycorhizal association with plants. How does the plant derive benefits from this association?
- How Does the Activity of Each One of the Following Help in Organic Farming? Cyanobacteria
- Farmers are often suggested to use the following organism in their crop land so as to improve the soil fertility. Explain. Anabaena
- Explain the Interrelationship Between Organic Farming and Biofertilizers, with the Help of Any Three Suitable Examples.
- Farmers are often suggested to use the following organism in their crop land so as to improve the soil fertility. Explain. Rhizobium
