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Questions and Answers
What is the approximate size range of bacteria?
What is the approximate size range of bacteria?
Which type of bacteria occur in pairs after cell division in one plane?
Which type of bacteria occur in pairs after cell division in one plane?
Which type of movement is characteristic of motile bacteria with flagella?
Which type of movement is characteristic of motile bacteria with flagella?
Which morphology of bacteria is characterized by multiple flagella at one end?
Which morphology of bacteria is characterized by multiple flagella at one end?
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In what environments can bacteria be found thriving?
In what environments can bacteria be found thriving?
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What type of filamentous bacteria resembles fungi?
What type of filamentous bacteria resembles fungi?
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Which category of bacteria is primarily non-motile?
Which category of bacteria is primarily non-motile?
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What group of bacteria occurs in clusters after cell division in multiple planes?
What group of bacteria occurs in clusters after cell division in multiple planes?
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What is one characteristic that distinguishes photoautotrophic bacteria from green plants?
What is one characteristic that distinguishes photoautotrophic bacteria from green plants?
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Which type of bacteria derive energy by oxidizing hydrogen sulfide?
Which type of bacteria derive energy by oxidizing hydrogen sulfide?
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Which of the following are classified as heterotrophic bacteria?
Which of the following are classified as heterotrophic bacteria?
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What term describes bacteria that can manufacture their own organic food from inorganic substances?
What term describes bacteria that can manufacture their own organic food from inorganic substances?
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What do nitrifying bacteria primarily oxidize to derive energy?
What do nitrifying bacteria primarily oxidize to derive energy?
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Which of the following is a key feature of parasitic bacteria?
Which of the following is a key feature of parasitic bacteria?
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What is the primary method of reproduction in bacteria known for its speed and simplicity?
What is the primary method of reproduction in bacteria known for its speed and simplicity?
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What is the primary role of fimbriae in bacterial cells?
What is the primary role of fimbriae in bacterial cells?
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Which type of bacteria is known for living off of dead organic matter?
Which type of bacteria is known for living off of dead organic matter?
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Which type of bacteria derives energy from the oxidation of ferrous ions?
Which type of bacteria derives energy from the oxidation of ferrous ions?
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What is the process called when bacteria transfer part of their nuclear material to form mutant cells?
What is the process called when bacteria transfer part of their nuclear material to form mutant cells?
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Which of the following processes is NOT part of the nitrogen cycle?
Which of the following processes is NOT part of the nitrogen cycle?
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What process helps in the decomposition of organic material and returns carbon to the atmosphere?
What process helps in the decomposition of organic material and returns carbon to the atmosphere?
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Which of the following best describes endospores?
Which of the following best describes endospores?
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What role do bacteria play in the carbon cycle?
What role do bacteria play in the carbon cycle?
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In what condition is asexual reproduction in bacteria more likely to occur?
In what condition is asexual reproduction in bacteria more likely to occur?
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What process converts ammonium ions to nitrite?
What process converts ammonium ions to nitrite?
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Which bacterium is commonly used for biological control of insect pests?
Which bacterium is commonly used for biological control of insect pests?
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What is the final nitrogenous product released into the atmosphere during denitrification?
What is the final nitrogenous product released into the atmosphere during denitrification?
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What is bioremediation primarily used for?
What is bioremediation primarily used for?
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Which compound is broken down by anaerobic bacteria during sewage treatment?
Which compound is broken down by anaerobic bacteria during sewage treatment?
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Which of the following is NOT a product of dairy fermentation?
Which of the following is NOT a product of dairy fermentation?
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What microorganism is specifically mentioned for decomposing toxic waste in bioremediation?
What microorganism is specifically mentioned for decomposing toxic waste in bioremediation?
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What type of respiration do bacteria perform during denitrification?
What type of respiration do bacteria perform during denitrification?
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Study Notes
Bacteria: Tiny but Mighty
- Bacteria are single-celled organisms belonging to the prokaryotic domain.
- They are incredibly diverse and can be found in a wide range of environments, including extreme conditions like hot springs, high salt concentrations, and even within the human stomach.
- Bacteria range in size from 1 to 15 microns.
- Bacteria play a crucial role in various ecological processes and are essential for life on Earth.
Bacterial Shapes
- Four main shapes: Spherical, Rod-shaped, Spiral-shaped, Filamentous.
- Spherical bacteria: Micrococci, Diplococci, Tetracocci, Sarcinae, Streptococci, Staphyllococci.
- Rod-shaped bacteria: Bacilli, Diplobacilli, Streptobacilli.
- Spiral-shaped bacteria: Vibriones, Spirilla, Spirochaetes.
- Filamentous bacteria: Actinomycetes, resemble fungi.
Bacterial Movement
- Bacteria can be motile or non-motile.
- Motility is achieved through flagella or creeping movements.
- Flagella can be arranged in various patterns: Monotrichous, Lophotrichous, Amphitrichous, Peritrichous.
Bacterial Cell Structure
- The bacterial cell consists of several key structures:
- Capsule: Outer layer, provides protection.
- Cell wall: Rigid structure, maintaining cell shape.
- Cytoplasmic membrane: Controls movement of substances in and out of the cell.
- Cytoplasm: Contains the cell's genetic material and organelles.
- Flagellum: For movement.
- Fimbriae: Hair-like structures for attachment.
- Nuclear material: Genetic material, not enclosed in a nucleus.
Bacterial Metabolism
- Two main metabolic types: Autotrophic and Heterotrophic.
Autotrophic Bacteria
- Produce their own food from inorganic substances.
- Use carbon dioxide as a carbon source and hydrogen sulfide, ammonia, or hydrogen as a hydrogen source.
- Two types: Photoautotrophic and Chemosynthetic.
Photoautotrophic Bacteria
- Utilize light energy for photosynthesis, similar to plants.
- Contain pigments in membrane-bound lamellae (thylakoids) for capturing light energy.
- Their photosynthesis is different from plant photosynthesis, as water is not used as a hydrogen donor, and no oxygen is released.
Chemosynthetic Bacteria
- Synthesize organic molecules using energy derived from the oxidation of inorganic substances.
- Examples:
- Nitrifying bacteria: Oxidize ammonia into nitrates (Nitrosomonas, Nitrobacter).
- Sulphur bacteria: Oxidize hydrogen sulfide to sulphur (Thiobacillus, Beggiatoa).
- Iron bacteria: Oxidize ferrous ions into ferric form (Ferrobacillus, Gallionella).
Heterotrophic Bacteria
- Unable to produce their own food.
- Rely on external sources of organic compounds.
- Three main types: Symbiotic, Parasitic, Saprophytic.
Symbiotic Bacteria
- Live in mutually beneficial relationships with other organisms.
- Provide essential nutrients to their host, often benefiting the host in return.
- Example: Nitrogen-fixing bacteria (Rhizobium, Pseudomonas) in root nodules of leguminous plants.
Parasitic Bacteria
- Live within the bodies of plant or animal hosts, obtaining nutrients from their host.
- Many are pathogenic, causing diseases by exploiting the host or releasing toxins.
Saprophytic Bacteria
- Decompose dead organic matter for their nutrition.
- Play a crucial role in recycling nutrients in ecosystems.
Bacterial Reproduction
-
Three main methods:
- Vegetative reproduction: Rapid binary fission, dividing into two daughter cells.
- Asexual reproduction: Occurs under unfavorable conditions.
- Conidia formation: Specialized, resistant cells released by some bacteria.
- Endospores: Highly resistant, dormant structures produced by certain bacteria, able to survive extreme conditions.
- Sexual reproduction: Less common, involving the transfer of genetic material between cells.
Bacteria in the Living World
- Critical roles in various cycles:
- Carbon cycle:
- Photosynthetic bacteria fix carbon dioxide into organic molecules.
- Decomposers break down organic molecules, releasing carbon dioxide back into the atmosphere.
- Carbon is stored in rocks and fossil fuels.
- Nitrogen cycle:
- Nitrogen-fixing bacteria convert atmospheric nitrogen into usable forms.
- Nitrifying bacteria convert ammonia to nitrates.
- Denitrifying bacteria convert nitrates back to atmospheric nitrogen.
- Carbon cycle:
Biological Control
- Utilizing microorganisms (including bacteria) to control insect pests of crops.
- Microbial insecticides target insect digestive systems, causing disease.
- Examples: Bacillus thuringiensis for pest control, bacteria for controlling mosquito-borne diseases (Malaria).
Bioremediation
- Using organisms to remove or neutralize pollutants.
- Bioremediators break down toxic waste into harmless substances.
- Example: Pseudomonas cepacia for decomposing toxic waste.
Anaerobic Sewage Treatment
- Breaking down complex organic matter in sewage into simpler substances using anaerobic bacteria.
- Produces methane and other gases.
- Example: Colistridium spp.
Dairy Products
- Bacteria are used in the production of various dairy products:
- Buttermilk
- Yogurt
- Sour cream
- Cheese
Bacteria in Medicine
- Pathogenic bacteria cause various human diseases.
- Some bacteria are used in the production of antibiotics and other medical treatments.
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Description
Explore the fascinating world of bacteria, their diverse shapes, and their vital ecological roles. This quiz covers the characteristics of bacteria, including their sizes, movements, and the significance they hold in various environments. Test your knowledge on these tiny but mighty organisms!
