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Questions and Answers
What do nitrifying bacteria convert ammonium into?
What do nitrifying bacteria convert ammonium into?
What do nitrogen-fixing bacteria provide to leguminous plants?
What do nitrogen-fixing bacteria provide to leguminous plants?
What essential function do gut bacteria perform in humans?
What essential function do gut bacteria perform in humans?
What is the final step in the nitrogen cycle?
What is the final step in the nitrogen cycle?
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Which of the following vitamins do gut bacteria help produce?
Which of the following vitamins do gut bacteria help produce?
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What is the primary structure that allows prokaryotic cells to move?
What is the primary structure that allows prokaryotic cells to move?
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Which of the following describes plasmids?
Which of the following describes plasmids?
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Which process allows prokaryotes to reproduce asexually?
Which process allows prokaryotes to reproduce asexually?
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What type of prokaryote requires oxygen for respiration?
What type of prokaryote requires oxygen for respiration?
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What distinguishes Gram-positive bacteria from Gram-negative bacteria?
What distinguishes Gram-positive bacteria from Gram-negative bacteria?
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What is a defining characteristic of prokaryotic cells?
What is a defining characteristic of prokaryotic cells?
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Why are nitrogen-fixing bacteria important for plants?
Why are nitrogen-fixing bacteria important for plants?
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Which of the following statements is true about Archaea?
Which of the following statements is true about Archaea?
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Which of the following structures are found in most prokaryotic cells?
Which of the following structures are found in most prokaryotic cells?
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What process involves the uptake of DNA from the environment by prokaryotic cells?
What process involves the uptake of DNA from the environment by prokaryotic cells?
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What are the two major domains of prokaryotes?
What are the two major domains of prokaryotes?
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Which feature distinguishes bacterial cell walls from archaeal cell walls?
Which feature distinguishes bacterial cell walls from archaeal cell walls?
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Which type of prokaryote thrives in very salty environments?
Which type of prokaryote thrives in very salty environments?
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What role do prokaryotes play in the ecosystem as decomposers?
What role do prokaryotes play in the ecosystem as decomposers?
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Where is the genetic material located in prokaryotic cells?
Where is the genetic material located in prokaryotic cells?
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What is the function of ribosomes in prokaryotic cells?
What is the function of ribosomes in prokaryotic cells?
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Which of the following is a term used for the jelly-like substance inside prokaryotic cells?
Which of the following is a term used for the jelly-like substance inside prokaryotic cells?
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Study Notes
Prokaryote Overview
- Prokaryotes are ancient, single-celled organisms lacking a nucleus and membrane-bound organelles.
- They are classified into two domains: Bacteria and Archaea.
- Prokaryotes are incredibly diverse and thrive in various environments.
Prokaryotic Cell Structure
- No Nucleus: Genetic material (DNA) is located in the nucleoid region, not enclosed by a membrane.
- Plasma Membrane: Controls what enters and exits the cell.
- Cell Wall: Provides support and protection, composed of peptidoglycan in bacteria and different substances in archaea.
- Cytoplasm: Jelly-like substance where cellular activities occur.
- Ribosomes: Smaller than eukaryotic ribosomes, responsible for protein synthesis.
- Flagella and Pili: Flagella are whip-like structures for movement, pili are hair-like structures for attachment.
Prokaryotic Genetics
- DNA is usually a single, circular chromosome.
- Many prokaryotes also have plasmids, small circular DNA molecules carrying advantageous genes.
- Plasmids can be transferred through conjugation, spreading beneficial traits.
Prokaryotic Reproduction
- Reproduction is primarily asexual through binary fission, a rapid process of cell division.
- Prokaryotes also engage in genetic exchange through transformation (uptake of environmental DNA), transduction (transfer via virus), and conjugation (direct DNA transfer).
Prokaryotic Metabolism
- Autotrophs: Produce their own food from inorganic substances (photoautotrophs use light, chemoautotrophs use chemical reactions).
- Heterotrophs: Obtain energy by consuming organic matter.
The Domain Bacteria
- Gram-Positive Bacteria: Thick peptidoglycan layer retains purple dye in Gram staining.
- Gram-Negative Bacteria: Thinner peptidoglycan layer with an outer membrane, appearing pink after counterstaining.
- Beneficial Bacteria: Play essential roles in digestion, nutrient cycling, and symbiotic relationships.
- Pathogenic Bacteria: Cause diseases by producing toxins, invading tissues, and triggering immune responses.
The Domain Archaea
- Distinct from Bacteria: Have different cell wall composition and membrane lipids.
- Extremophiles: Thrive in extreme environments (thermophiles in hot springs, halophiles in salty environments, methanogens in anaerobic conditions).
- Methanogenesis: Unique metabolic process producing methane as a byproduct.
Importance of Prokaryotes
- Decomposers and Nutrient Cycling: Break down dead organic matter and recycle nutrients, essential for ecosystem health.
- Symbiotic Relationships: Form beneficial partnerships with other organisms, impacting digestion, immune function, and plant growth.
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Description
Explore the fascinating world of prokaryotes, the ancient single-celled organisms that lack a nucleus. This quiz covers their unique cell structures, such as the plasma membrane and cell wall, as well as their genetic makeup. Test your knowledge on Bacteria and Archaea and how these organisms thrive in diverse environments.
