Every question from this NCERT chapter, with a detailed explanation.
With reference to microorganisms, consider the following statements: 1. They are classified into four major groups: bacteria, fungi, protozoa, and algae. 2. They can survive only in moderate climates and die in ice-cold or hot spring environments. 3. Some microorganisms are unicellular, while others are multicellular. Which of the statements given above is/are correct?
Which one of the following characteristics distinguishes viruses from other microorganisms?
Consider the following statements regarding the habitat of microorganisms: 1. They are found in air, water, and soil but not inside the bodies of animals. 2. They can exist freely as well as grow on other organisms. 3. They are capable of surviving in deserts and marshy lands. Which of the statements given above is/are correct?
Which one of the following human diseases is caused by a protozoan pathogen?
Consider the following pairs of microorganisms and their classification: 1. Aspergillus : Algae 2. Paramecium : Protozoa 3. Penicillium : Fungi 4. Spirogyra : Bacteria How many of the above pairs are correctly matched?
With reference to the classification of diseases, consider the following statements: 1. Typhoid and Tuberculosis (TB) are bacterial diseases. 2. Polio and Chicken pox are bacterial diseases. 3. Dysentery is caused by a virus. Which of the statements given above is/are correct?
The bacterium Lactobacillus plays a primary role in which one of the following processes?
Consider the following statements regarding the use of yeast: 1. It is used in the baking industry because it produces carbon dioxide during respiration. 2. It is used to prevent the fermentation of rice and fruit juices. 3. It acts on natural sugars present in grains to produce alcohol. Which of the statements given above is/are correct?
The metabolic process of converting sugar into alcohol by microbial action is known as:
With reference to the commercial use of microorganisms, consider the following statements: 1. Yeast is used for the large-scale production of acetic acid (vinegar). 2. Antibiotics are manufactured by growing specific microorganisms. 3. Bacteria are involved in the making of cheese and pickles. Which of the statements given above is/are correct?
What is the scientific basis for adding yeast to the dough in the preparation of bread?
With reference to antibiotics, consider the following statements: 1. They are medicines produced from microorganisms that kill or stop the growth of disease-causing microbes. 2. Penicillin was the first antibiotic discovered from a bacterial culture of E. coli. 3. Antibiotics are highly effective against viral diseases like cold and flu. Which of the statements given above is/are correct?
Which of the following are common antibiotics produced from bacteria and fungi? 1. Streptomycin 2. Aspirin 3. Erythromycin Select the correct answer using the code given below:
Consider the following statements regarding the discovery of Penicillin: 1. It was discovered by Louis Pasteur in 1929. 2. It was discovered while working on a culture of disease-causing bacteria. 3. The source of Penicillin was a mould (fungus). Which of the statements given above is/are correct?
What is the mechanism of action of a typical vaccine in the human body?
Which of the following diseases can be prevented by vaccination? 1. Cholera 2. Tuberculosis 3. Smallpox 4. Hepatitis Select the correct answer using the code given below:
Who among the following is credited with the discovery of the vaccine for smallpox in 1798?
With reference to the use of antibiotics in agriculture and animal husbandry, consider the following statements: 1. Antibiotics are mixed with the feed of livestock to check microbial infection. 2. They are ineffective in controlling any plant diseases. 3. Unnecessary use of antibiotics enhances the population of beneficial bacteria in the body. Which of the statements given above is/are correct?
The "Pulse Polio Programme" in India is primarily aimed at:
Consider the following statements regarding soil fertility: 1. Some bacteria and blue-green algae are able to fix nitrogen from the atmosphere. 2. These microbes deplete the soil of nitrogen and reduce its fertility. 3. These microbes are commonly called biological nitrogen fixers. Which of the statements given above is/are correct?
In what way do microorganisms primarily contribute to environmental sanitation?
Which of the following items can be converted into manure by the action of microbes? 1. Vegetable peels 2. Polythene bags 3. Broken plastic toys 4. Dry leaves Select the correct answer using the code given below:
The nitrogen-fixing bacterium Rhizobium forms a symbiotic association with:
With reference to "pathogens", consider the following statements: 1. Pathogens are beneficial microorganisms that protect humans from diseases. 2. They can enter the human body through air, water, or food. 3. Some pathogens require a vector like a mosquito to transmit disease. Which of the statements given above is/are correct?
Diseases that are transmissible from an infected individual to a healthy individual through vectors, air, or water are termed as:
Consider the following statements regarding disease carriers: 1. The housefly acts as a carrier by transferring pathogens from garbage to uncovered food. 2. The female Anopheles mosquito is the carrier of the dengue virus. 3. The female Aedes mosquito acts as a carrier of the malaria parasite. Which of the statements given above is/are correct?
Which one of the following is the most effective preventive measure against vector-borne diseases like malaria and dengue?
Match List I with List II and select the correct answer using the code given below: List I | List II A. Tuberculosis | 1. Virus B. Measles | 2. Bacteria C. Malaria | 3. Protozoa D. Cholera | 4. Bacteria
Consider the following statements regarding the transmission of Tuberculosis (TB): 1. It is caused by bacteria. 2. It is transmitted through water. 3. The patient should be kept in complete isolation. Which of the statements given above is/are correct?
Which one of the following diseases is primarily transmitted through contaminated water?
Which one of the following is a primary preventive measure against the spread of Cholera?
Hepatitis A is a viral disease primarily transmitted through:
Anthrax, a disease affecting both humans and livestock, is caused by a:
Who among the following scientists is credited with the discovery of the bacterium Bacillus anthracis?
Foot-and-mouth disease in cattle is caused by a:
Consider the following pairs of plant diseases and their causative microorganisms: 1. Citrus canker : Bacteria 2. Rust of wheat : Fungi 3. Yellow vein mosaic of bhindi : Virus How many of the above pairs are correctly matched?
The plant disease "Citrus canker" is primarily transmitted through:
Which one of the following plant diseases is transmitted by an insect vector?
Consider the following statements regarding the harmful effects of microorganisms on plants: 1. Microorganisms are incapable of causing diseases in crops like wheat and rice. 2. These diseases reduce the yield of crops. 3. These diseases can be controlled by using chemicals that kill the microbes. Which of the statements given above is/are correct?
With reference to food poisoning, consider the following statements: 1. It is caused by the consumption of food spoilt by microorganisms. 2. Microorganisms growing on food neutralize toxic substances. 3. Food poisoning can cause serious illness but is never fatal. Which of the statements given above is/are correct?
Which of the following chemicals are commonly used as preservatives in jams and squashes? 1. Sodium benzoate 2. Sulphuric acid 3. Sugar Select the correct answer using the code given below:
What is the mechanism by which common salt preserves meat and fish?
Sugar acts as a preservative in jams and jellies primarily by:
Consider the following statements regarding Pasteurization: 1. It involves boiling milk at 100°C for at least one hour. 2. After heating, the milk is suddenly chilled and stored. 3. This process prevents the growth of microbes. Which of the statements given above is/are correct?
With reference to the Nitrogen Cycle, consider the following statements: 1. The amount of nitrogen in the atmosphere remains more or less constant. 2. Plants and animals can take atmospheric nitrogen directly. 3. Viruses are the primary agents that convert atmospheric nitrogen into nitrogenous compounds. Which of the statements given above is/are correct?
Which one of the following is NOT a natural method of nitrogen fixation in the soil?
In the nitrogen cycle, what is the fate of nitrogenous wastes from dead plants and animals?
Consider the following statements regarding the role of bacteria in the nitrogen cycle: 1. Some bacteria fix atmospheric nitrogen into soil compounds. 2. Bacteria convert nitrogenous compounds in the soil into solid carbon. 3. Blue-green algae are also involved in fixing atmospheric nitrogen. Which of the statements given above is/are correct?
The symbiotic nitrogen-fixing relationship of Rhizobium is specific to which group of plants?
Consider the following statements about the "Carrier" of a disease: 1. A carrier is an organism that always dies immediately upon contracting a pathogen. 2. The housefly is a carrier because pathogens stick to its body. 3. Mosquitoes are carriers because they breed in water. Which of the statements given above is/are correct?
Salting is applied to raw mangoes and tamarind primarily to:
Consider the following statements about the Nitrogen Cycle: 1. Nitrogen gas constitutes 78% of our atmosphere. 2. Nitrogen is completely absent in proteins and vitamins. 3. The cycle ensures that the percentage of nitrogen in the atmosphere constantly increases. Which of the statements given above is/are correct?
Which one of the following is a viral disease affecting plants?
Consider the following statements regarding the preservation of food by heat and cold: 1. Boiling kills many microorganisms. 2. Low temperature in a refrigerator accelerates the growth of microbes. 3. Pasteurization combines both heating and sudden chilling. Which of the statements given above is/are correct?
In the context of immunology, what are "antibodies"?
Which one of the following groups of microorganisms is responsible for the plant disease known as "Rust of wheat"?
In the context of baking and fermentation, which one of the following statements best describes the activity of yeast?
Consider the following statements regarding the environment: 1. Manure is formed by the accumulation of non-biodegradable plastic waste. 2. Recycling is a better alternative to burning for managing plastic waste. 3. Microorganisms degrade harmful and smelly substances. Which of the statements given above is/are correct?
Which one of the following diseases is classified as a "communicable disease"?
With reference to the Nitrogen Cycle, what is the role of lightning?
Which of the following statements is correct regarding the use of microorganisms in medicine?
Consider the following statements about Rhizobium bacteria: 1. They live in the root nodules of leguminous plants. 2. They have a parasitic relationship where they harm the plant. 3. They convert atmospheric oxygen into liquid nitrogen. Which of the statements given above is/are correct?
The metabolic process by which yeast converts sugar into alcohol is primarily utilised in the production of:
With reference to the prevention of Dengue, which mosquito acts as the carrier of the dengue virus?
Which one of the following statements regarding microorganisms is NOT correct?