Chpt 26 Beneficial Use Of Microorganisms Flashcards
- Which of the following is NOT a way that microorganisms benefit agriculture a) Increasing nutrient availability b) Promoting plant growth c) Causing plant diseases d) Controlling pests
Answer c) Causing plant diseases Explanation Microorganisms play numerous beneficial roles in agriculture including increasing nutrient availability promoting plant growth and controlling pests However some microorganisms can be detrimental to plant health by causing diseases
- What is the rhizosphere a) The layer of soil directly surrounding plant roots b) The internal tissues of plant roots c) The atmosphere surrounding a plant d) The water table below a plant
Answer a) The layer of soil directly surrounding plant roots Explanation The rhizosphere is a specific zone of soil directly influenced by plant roots It is a rich and diverse microbial habitat where plant-microorganism interactions significantly impact plant health and nutrient uptake
- Which of these describes a symbiotic relationship between bacteria and plants a) Bacteria living independently in the soil b) Bacteria living within plant tissues without causing harm c) Bacteria forming nodules on legume roots to fix nitrogen d) Bacteria decomposing organic matter in the soil
Answer c) Bacteria forming nodules on legume roots to fix nitrogen Explanation A symbiotic relationship implies a mutually beneficial interaction between two organisms In this case rhizobia bacteria form nodules on the roots of leguminous plants providing fixed nitrogen to the plant in exchange for nutrients and a protected environment
- How do phosphorus-solubilizing bacteria (PSB) benefit plants a) They convert atmospheric nitrogen into a usable form for plants b) They produce hormones that stimulate plant growth c) They break down insoluble phosphates making them available for plant uptake d) They protect plants from pathogenic fungi
Answer c) They break down insoluble phosphates making them available for plant uptake Explanation Phosphorus is an essential nutrient for plant growth but a significant portion of it exists in the soil in insoluble forms PSB have the ability to convert these insoluble phosphates into soluble forms that can be readily absorbed by plants This reduces the reliance on chemical fertilizers which can have negative environmental impacts
- Which of the following is an example of a free-living nitrogen-fixing bacterium a) Rhizobium b) Azotobacter c) Bradyrhizobium d) Sinorhizobium
Answer b) Azotobacter Explanation Azotobacter is an example of a free-living nitrogen-fixing bacterium It can convert atmospheric nitrogen into ammonia without forming a symbiotic relationship with plants In contrast Rhizobium Bradyrhizobium and Sinorhizobium are all symbiotic nitrogen-fixers that form nodules on legume roots
- What is the role of PGPR in phytohormone production a) They inhibit the production of plant hormones leading to dwarfism b) They synthesize and release plant hormones promoting growth and development c) They break down excess plant hormones regulating their levels in plants d) They have no role in plant hormone production
Answer b) They synthesize and release plant hormones promoting growth and development Explanation PGPR contribute significantly to plant growth by producing various phytohormones including auxins cytokinins gibberellins ethylene and abscisic acid These hormones regulate essential plant processes such as cell division elongation root development flowering and stress responses
- Which of the following is a commonly used microbial bio-insecticide a) Pseudomonas fluorescens b) Bacillus thuringiensis c) Escherichia coli d) Saccharomyces cerevisiae
Answer b) Bacillus thuringiensis Explanation Bacillus thuringiensis (BT) is a bacterium that produces a crystalline protein toxic to many insect pests BT-based bio-insecticides are widely used as a sustainable alternative to chemical pesticides offering a more environmentally friendly approach to pest control
- How do microorganisms contribute to soil fertility a) By absorbing nutrients from the atmosphere b) By releasing toxic substances that kill beneficial soil organisms c) By decomposing organic matter and releasing nutrients d) By compacting the soil making it harder for plant roots to grow
Answer c) By decomposing organic matter and releasing nutrients Explanation Microorganisms play a crucial role in the breakdown of complex organic matter in the soil This process releases essential nutrients such as nitrogen phosphorus and potassium back into the soil making them available for plant uptake
- Which of the following is an example of a fermented food product made using microorganisms a) Bread b) Yogurt c) Cheese d) All of the above
Answer d) All of the above Explanation Microorganisms particularly bacteria and yeasts are essential for the production of various fermented food products Yeast is used in bread making to leaven the dough while bacteria are crucial for the fermentation of yogurt and cheese giving them their characteristic flavors and textures
- What is the definition of microbial biotechnology a) The study of microorganisms in their natural habitats b) The use of microorganisms to produce commercially valuable products c) The development of vaccines against microbial diseases d) The genetic modification of microorganisms for research purposes
Answer b) The use of microorganisms to produce commercially valuable products Explanation Microbial biotechnology encompasses the exploitation of microorganisms for industrial purposes It involves using their metabolic processes to produce a wide range of products including pharmaceuticals enzymes biofuels and food additives
- What is the meaning of “fermentation” in the context of microbial biotechnologya) The process of boiling fruit or grain to extract juicesb) The growth of microorganisms under anaerobic conditionsc) The production of alcoholic beverages using yeastd) The preservation of food by adding salt or sugar
Answer: b) The growth of microorganisms under anaerobic conditionsExplanation: In microbial biotechnology fermentation refers to the controlled cultivation of microorganisms often under anaerobic oxygen-limited conditions to produce desired products this process harnesses the metabolic capabilities of microorganisms to convert raw materials into valuable compounds
- What are the two main objectives of microbial biotechnologya) Producing microorganisms and preventing their growthb) Preventing microorganism growth and enhancing product formationc) Producing a desired product and preventing microorganism contaminationd) Preventing microorganism contamination and enhancing product quality
Answer: c) Producing a desired product and preventing microorganism contaminationExplanation: Microbial biotechnology aims to harness the metabolic capabilities of microorganisms to produce valuable products while simultaneously controlling the growth of unwanted or contaminating microorganisms
- Which of the following is a criterion for selecting industrially important microorganismsa) The organism must be pathogenic to humansb) The organism must be difficult to grow in large quantitiesc) The organism must be genetically stable and amenable to manipulationd) The organism must produce toxic by-products
Answer: c) The organism must be genetically stable and amenable to manipulationExplanation: For industrial applications microorganisms must possess certain characteristics including genetic stability ease of cultivation and the ability to be genetically modified if needed these traits ensure consistent production and allow for optimization of the desired product yield
- What is single-cell protein SCPa) A protein extracted from a single bacterial cellb) Microbial biomass produced for use as a food or feed supplementc) A protein synthesized using recombinant DNA technologyd) A protein found only in unicellular algae
Answer: b) Microbial biomass produced for use as afood or feed supplementExplanation: Single-cell protein SCP refers to the dried biomass of microorganisms such as bacteria yeast or algae it is a rich source of protein and can be used as a food supplement for humans or as animal feed
- Which of the following is an example of a productmade through recombinant DNA technologya) Insulinb) Ethanolc) Citric acidd) Yogurt
Answer: a) InsulinExplanation: Recombinant DNA technology allows for the insertion of genes from one organism into another enabling the production of valuable proteins in a host organism insulin used to treat diabetes is an example of a product produced through this technology
