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Bacteria and Archaea - General Biology

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이 집합의 용어 (22)

  • What are the three domains of life?

    The three domains are Bacteria, Archaea, and Eukarya.

  • What distinguishes prokaryotes from eukaryotes?

    Prokaryotes lack a nucleus and membrane-enclosed organelles, and have a single circular DNA molecule in the nucleoid region.

  • What is the significance of stromatolites?

    Stromatolites are fossilized bacterial mats dating back 3.5 billion years, representing some of Earth's oldest known life forms.

  • What environments can prokaryotes inhabit?

    Prokaryotes live in diverse environments including acidic, salty, cold, and hot habitats, often where other organisms cannot survive.

  • What are extremophiles?

    Extremophiles are archaea that thrive in extreme conditions such as high salinity (halophiles) or high temperature (thermophiles).

  • What roles do bacteria and archaea play in ecosystems?

    They recycle chemicals, decompose organic matter, fix nitrogen, and increase soil nutrients for plants.

  • How do bacteria interact with humans?

    Bacteria can be pathogens or beneficial, aiding digestion and playing roles in agriculture, industry, and research.

  • What is the typical size range of prokaryotic cells?

    Most prokaryotic cells range from 0.5 to 5 micrometers, much smaller than eukaryotic cells.

  • What are the common shapes of prokaryotic cells?

    Prokaryotes commonly have spherical (cocci), rod-shaped (bacilli), or spiral shapes.

  • What is peptidoglycan and where is it found?

    Peptidoglycan is a polymer of sugars and peptides found in bacterial cell walls, providing structural support.

  • How do archaeal cell walls differ from bacterial cell walls?

    Archaeal cell walls lack peptidoglycan and instead contain glycoproteins.

  • What is the function of a prokaryotic capsule?

    The capsule stabilizes cells, helps form colonies, limits dehydration, and protects against host immune responses.

  • What are endospores?

    Endospores are metabolically inactive, highly resistant structures formed by some prokaryotes to survive harsh conditions.

  • What are fimbriae and their function?

    Fimbriae are hair-like structures that allow prokaryotes to attach to surfaces or other cells, aiding in colony formation.

  • What is chemotaxis in bacteria?

    Chemotaxis is the movement of bacteria toward or away from chemical stimuli.

  • How do bacterial flagella differ from eukaryotic flagella?

    Bacterial and archaeal flagella are made of different proteins than eukaryotic flagella, indicating independent evolutionary origins.

  • Describe the prokaryotic genome structure.

    Prokaryotes have a single circular chromosome and may have smaller DNA rings called plasmids.

  • What factors promote genetic diversity in prokaryotes?

    Rapid reproduction, mutation, and genetic recombination (transformation, transduction, conjugation) promote diversity.

  • What is horizontal gene transfer?

    Horizontal gene transfer is the movement of genes between individuals of different species.

  • What are the four major modes of prokaryotic nutrition?

    Phototrophs (light energy), chemotrophs (chemical energy), autotrophs (CO2 carbon source), and heterotrophs (organic carbon source).

  • What are obligate aerobes, obligate anaerobes, and facultative anaerobes?

    Obligate aerobes require oxygen, obligate anaerobes are poisoned by oxygen, facultative anaerobes can survive with or without oxygen.

  • What is nitrogen fixation?

    Nitrogen fixation is the conversion of atmospheric nitrogen (N2) to ammonia (NH3) by some prokaryotes, making nitrogen available to other organisms.