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Questions and Answers
Which of the following is NOT a type of microorganism?
What are the shapes of bacteria typically recognized?
Which microorganism is known to infect all life forms?
Who was the first to observe microorganisms using a microscope?
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Which of the following can be a result of the action of certain microorganisms?
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Which type of microorganism does NOT produce chlorophyll?
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Which microorganism is commonly found in soil and aquatic environments and is single-celled?
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What did Louis Pasteur conclude about microorganisms in the air?
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What is the typical temperature range in which most microorganisms thrive?
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Which of the following classifications correctly describes microorganisms that do not require oxygen for respiration?
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What role do fungi and bacteria play in enhancing soil fertility?
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Which type of microorganisms live in root nodules of legumes and assist in nitrogen fixation?
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What is the main requirement for microbial growth in terms of moisture?
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Which type of microorganisms perform photosynthesis?
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What is one of the primary consequences of the decay and decomposition performed by saprophytic microorganisms?
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In which type of environment do many microorganisms thrive?
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Which form of nitrogen can plants directly use for their growth?
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What is the primary role of nitrifying bacteria in the nitrogen cycle?
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During which process are ammonium and nitrate compounds released back into the soil for use by plants?
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What do nitrogen-fixing bacteria convert atmospheric nitrogen to?
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How do plants primarily obtain nitrates from the soil?
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What happens to nitrogen compounds when plants and animals die?
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Which environmental processes contribute to the formation of nitrates in the soil?
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What is the effect of denitrifying bacteria in the nitrogen cycle?
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Study Notes
Microorganisms
- Microorganisms are tiny, single-celled living organisms that can be seen only with a microscope
- They include bacteria, viruses, protozoa, fungi and algae.
- They are found in a wide variety of environments, including inside other organisms.
Bacteria
- Bacteria were among the first living things to appear on Earth.
- They have different shapes: spherical (cocci), spiral (spirilla) and rod-shaped (bacilli).
- Examples include Streptococcus and Lactobacillus.
Viruses
- Viruses infect all life forms.
- They come in various shapes and sizes.
- Examples include the papillomavirus (can cause cancer) and the varicella zoster virus (chickenpox virus).
Protozoa
- Protozoa are single-celled organisms that thrive in soil and aquatic environments.
- Examples include Amoeba and Euglena.
Fungi
- Fungi are plant-like organisms that do not contain chlorophyll.
- Examples include mushrooms and yeast.
Algae
- Algae include single-celled and multicellular organisms.
- They are simple plant-like organisms found in water bodies, rocks and snow.
- Examples include Spirogyra and Chlorella.
Milestones in Microorganism Discovery
- Antonie van Leeuwenhoek (1632-1723) first observed microorganisms with the help of his microscope.
- Louis Pasteur (1822-1895) discovered that microorganisms in the air spoil food and are the cause of fermentation and decay, as well as diseases.
- Robert Koch (1843-1910) developed techniques for handling bacteria to study anthrax and prove it was caused by specific microorganisms.
- Joseph Lister (1827-1912) was the first to eliminate bacteria from operating theatres by using carbolic acid, a disinfectant.
Where are Microorganisms Found?
- Microorganisms are found in almost every kind of environment, including inside other organisms.
- A single gram of soil can contain a vast number of bacteria.
- The air you breathe, your skin, fingernails, and intestines all harbor microorganisms.
Conditions for Microorganism Growth
- Different microorganisms have different needs and grow in a wide range of conditions.
- Oxygen: Some require oxygen (aerobic) while others do not (anaerobic).
- Water: Moisture is essential for most microorganisms to thrive.
- Temperature: Some microorganisms can tolerate extreme temperatures, but most thrive between 25 °C and 38 °C.
- Darkness: Many microorganisms thrive in dark places, but photosynthetic microorganisms need light.
- Food Supply: Microorganisms live and feed on a wide range of materials, including dead organisms (saprophytes), tissues of host organisms (parasites), and through photosynthesis.
Useful Microorganisms
- Microorganisms are important for increasing soil fertility.
- Bacteria and fungi decompose dead organisms and organic matter, releasing nutrients back into the soil.
- Nitrogen-fixing bacteria, like Rhizobium, convert nitrogen to ammonia in legume root nodules, increasing soil fertility.
Nitrogen Cycle - A circular pathway of nitrogen in nature
- Nitrogen is the most abundant element in Earth's atmosphere, but most organisms cannot use it directly.
- Nitrogen-fixing bacteria convert atmospheric nitrogen into ammonia.
- Nitrifying bacteria convert ammonia into nitrites and then nitrates.
- Plants take in nitrates, and animals obtain nitrogen through consuming plants or other animals.
- Decomposers break down dead organisms and release ammonia back into the soil, restarting the cycle.
- Denitrifying bacteria convert nitrates back into atmospheric nitrogen.
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Description
Test your knowledge on various microorganisms including bacteria, viruses, protozoa, fungi, and algae. This quiz covers their characteristics, examples, and environments. Perfect for biology students learning about these fundamental organisms.
