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Questions and Answers
What is the primary mode of reproduction for bacteria?
What is the primary mode of reproduction for bacteria?
What condition can cause bacteria to reproduce every 20 minutes?
What condition can cause bacteria to reproduce every 20 minutes?
Which structure allows bacteria to survive extreme conditions?
Which structure allows bacteria to survive extreme conditions?
During which process do bacteria transfer genetic material to increase genetic diversity?
During which process do bacteria transfer genetic material to increase genetic diversity?
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How do bacteria typically divide during binary fission?
How do bacteria typically divide during binary fission?
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What is the relationship between the parent cell and bacteria produced by fission?
What is the relationship between the parent cell and bacteria produced by fission?
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What is the main component of the cytoplasm in bacterial cells?
What is the main component of the cytoplasm in bacterial cells?
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How does bacterial reproduction time vary?
How does bacterial reproduction time vary?
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Which type of bacteria exclusively feeds on dead materials?
Which type of bacteria exclusively feeds on dead materials?
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What structure allows Bacillus subtilis to survive extreme conditions?
What structure allows Bacillus subtilis to survive extreme conditions?
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Which method is NOT a way that diseases can be communicated?
Which method is NOT a way that diseases can be communicated?
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Which of the following is a harmful effect of bacteria?
Which of the following is a harmful effect of bacteria?
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Which of the following bacteria is important for nutrient recycling in soil?
Which of the following bacteria is important for nutrient recycling in soil?
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What is the primary role of bacteria in the digestive systems of cows?
What is the primary role of bacteria in the digestive systems of cows?
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Which of the following is not a common shape of bacteria?
Which of the following is not a common shape of bacteria?
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How do decomposer bacteria benefit the environment?
How do decomposer bacteria benefit the environment?
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What defines bacteria as prokaryotes?
What defines bacteria as prokaryotes?
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Which of the following correctly describes the capsule structure of a bacteria cell?
Which of the following correctly describes the capsule structure of a bacteria cell?
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Bacteria are classified into which of the following shapes?
Bacteria are classified into which of the following shapes?
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What is the primary function of ribosomes in bacteria?
What is the primary function of ribosomes in bacteria?
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Which part of the bacterial cell is responsible for locomotion?
Which part of the bacterial cell is responsible for locomotion?
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Among the structures listed, which one is a thick outer covering that maintains the shape of the bacterial cell?
Among the structures listed, which one is a thick outer covering that maintains the shape of the bacterial cell?
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Which feature allows bacteria to adhere to other cells?
Which feature allows bacteria to adhere to other cells?
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What is the composition of the nucleoid in a bacterial cell?
What is the composition of the nucleoid in a bacterial cell?
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What characteristic environment do bacteria thrive in?
What characteristic environment do bacteria thrive in?
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Which type of bacteria are known to produce their own food?
Which type of bacteria are known to produce their own food?
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Study Notes
Lesson 7.1 What are Bacteria?
- Bacteria are unicellular, microscopic prokaryotes.
- Prokaryotes lack a nucleus and membrane-bound organelles.
- Bacteria are found almost everywhere on Earth – in water, soil, air, food, skin, and inside the body.
- Bacteria prefer warm, dark, and moist environments.
- Bacteria are classified into three main shapes:
- Spiral (spirilla)
- Rod-shaped (bacilli)
- Round (cocci)
Types of Bacteria
- Bacteria- get food from an outside source
- Blue-green bacteria - make their own food
Bacterial Cell Structures
- Capsule: Protects the cell from drying out and helps it adhere to surfaces (food or other cells)
- Cell wall: A thick outer layer that maintains the overall shape of the bacterial cell.
- Ribosomes: The site of protein synthesis; they give the cytoplasm a granular appearance in electron micrographs.
- Nucleoid: A ring of DNA.
- Flagella: Whip-like tails for locomotion in some bacteria.
- Pili: Hollow hair-like structures made of protein. Allow bacteria to attach to other cells.
- Cytoplasm: Clear jelly-like material filling most of the cell.
Bacterial Reproduction
- Binary Fission: The process of one organism dividing into two organisms. It is a type of asexual reproduction.
- During fission, the circular main chromosome makes a copy of itself, and then divides into two.
- Reproduction time depends on conditions. Reproduction is more rapid in warm, dark and moist conditions, sometimes every 20 minutes. A single bacterium can become millions in a matter of hours.
- New organisms are not produced during conjugation; so this is not considered reproduction.
Bacterial Conjugation and Recombination
- Bacteria produced by binary fission are identical to the parent cell.
- Conjugation results in the transfer of DNA between two bacteria of the same species.
- Genetic variation increases due to a new combination of genes, increasing genetic diversity in a species.
Bacterial Survival
- Endospore: A thick-walled structure that forms inside the cell. Allows bacteria to survive harsh conditions, such as boiling, freezing and extremely dry conditions. It has the nuclear materials and cytoplasm inside.
- Endospores are highly resistant and can withstand radiation, UV light, and boiling at 120°C for 15 minutes.
- Endospores are a major cause of food poisoning.
- Bacteria can survive months or even centuries in their endospore form.
Bacteria: Food Sources
- Parasites: Bacteria that feed on living things.
- Saprophytes: Bacteria that use dead matter for food. They are exclusively saprophytes.
- Decomposers: Bacteria that break down dead matter into simple chemicals, releasing minerals and nutrients back into the soil. This is beneficial to the environment and other organisms that need these minerals.
Harmful Bacteria
- Some bacteria cause diseases.
- Animals can spread diseases to humans.
- Communicable disease: A disease passed from one organism to another; possible transmission through the air, touching infected objects (clothing, food, silverware, toothbrushes), or drinking water containing bacteria.
- Harmful bacteria can accumulate as plaque on teeth.
Helpful Bacteria
- Decomposers recycle nutrients into the soil.
- Some bacteria assist in digestion (e.g., in cows' stomachs)
- Used to produce antibiotics and industrial chemicals.
- Used to make foods like yogurt, cottage cheese, Swiss cheese, sour cream, and buttermilk.
- Used to treat sewage.
Bacteria Shapes Quiz Questions:
- Which is not a common bacterial shape? - Square
Bacterial Processes Quiz Questions:
- Which process increases genetic diversity in bacteria?: Transfer of plasmid strand
Bacteria Characteristics Quiz Question:
- Which is not a characteristic of bacteria? - They have a membrane-bound organelle
Bacterial Structure Function Quiz Question:
- What is the function of the structure labeled A in the bacterium image?: Attach to surfaces.
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Description
Explore the fascinating world of bacteria in this quiz. Learn about their classifications, cell structures, and the environments they thrive in. Discover the differences between various types of bacteria and their unique characteristics.
