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General Biology: Prokaryotes, Eukaryotes, and Animal Diversity

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이 집합의 용어 (29)

  • Define prokaryote

    A prokaryote is a unicellular organism without a nucleus or membrane-bound organelles, including Bacteria and Archaea.

  • List features that define prokaryotes

    Prokaryotes have no nucleus, circular DNA, lack membrane-bound organelles, have cell walls, reproduce asexually, and are typically smaller than eukaryotic cells.

  • Compare Bacteria and Archaea similarities

    Both are prokaryotes, unicellular, lack nuclei, have circular DNA, reproduce asexually, and have similar cell sizes and shapes.

  • Distinguishing features of Bacteria vs Archaea

    Bacteria have peptidoglycan in cell walls; Archaea have unique lipids in membranes and lack peptidoglycan. Archaea often live in extreme environments.

  • How do organisms' energy, electron, and carbon sources determine metabolism?

    Metabolic pathways depend on how organisms obtain energy (light or chemicals), electrons (organic or inorganic), and carbon (organic or CO2).

  • Importance of oxygenic photosynthesis in cyanobacteria

    Oxygenic photosynthesis evolved ~2.5 billion years ago, producing oxygen that enabled aerobic metabolism and changed Earth’s atmosphere.

  • Why did oxygen take time to accumulate in the atmosphere?

    Oxygen initially reacted with minerals and organic matter, delaying atmospheric accumulation despite photosynthesis.

  • Describe prokaryotic reproduction

    Prokaryotes reproduce mainly by binary fission, a form of asexual reproduction producing two identical cells.

  • Three mechanisms of lateral gene transfer in prokaryotes

    Transformation, transduction, and conjugation; these complicate phylogenies by transferring genes across lineages.

  • Explain nitrogen fixation and its importance

    Nitrogen fixation converts atmospheric N2 into ammonia, making nitrogen available to plants for growth.

  • Challenges and benefits of bioremediation by prokaryotes

    Benefits: degrade pollutants; Challenges: efficiency varies, potential toxin release, and environmental conditions affect success.

  • Examples of bacterial interactions with eukaryotes

    Symbiosis like gut microbiomes aiding digestion, nitrogen-fixing bacteria in plant roots, and pathogens causing disease.

  • How do microbiomes shape our lives?

    Microbiomes influence digestion, immunity, and health; threats include antibiotics, diet changes, and infections.

  • Major symptoms of bacterial diseases discussed

    Symptoms vary but include fever, diarrhea, respiratory issues; transmission often via contact, ingestion, or vectors.

  • Five major synapomorphies of Eukarya

    Nucleus, membrane-bound organelles, linear chromosomes, cytoskeleton, and mitosis/meiosis; each provides cellular complexity and regulation.

  • Explain the infolding hypothesis for the nucleus

    The nucleus evolved from infolded plasma membrane enclosing DNA; supported by membrane continuity and nuclear pores.

  • Three-Domain Hypothesis and recent updates

    Life divided into Bacteria, Archaea, and Eukarya; recent data suggest Eukarya evolved within Archaea, sister to Asgard Archaea.

  • Describe primary endosymbiosis

    Mitochondria and chloroplasts originated when a eukaryote engulfed bacteria; evidence includes double membranes and own DNA.

  • Evolutionary benefits of sexual reproduction

    Increases genetic diversity, enabling adaptation and survival in changing environments.

  • Define multicellularity and its evolutionary significance

    Multicellularity is organisms composed of multiple cells; it allows specialization and larger body size, evolving multiple times in eukaryotes.

  • Characteristics all animals share

    Multicellularity, heterotrophy, lack of cell walls, motility at some life stage, and specialized tissues.

  • Types of animal symmetry

    Asymmetry (no symmetry), radial (symmetry around a central axis), bilateral (left-right symmetry), pentaradial (five-part radial symmetry).

  • What is a coelom?

    A fluid-filled body cavity lined with mesoderm; distinguishes coelomates from acoelomates and pseudocoelomates.

  • Difference between complete and incomplete guts

    Complete gut has two openings (mouth and anus); incomplete gut has one opening serving both functions.

  • What is cephalization and why is it found in bilaterally symmetrical animals?

    Concentration of sensory organs and nervous tissue at the head; aids directional movement and processing.

  • Role of HOX gene complex in animal evolution

    HOX genes control body plan development; their evolution enabled complex body structures and diversification.

  • Key traits of Phylum Porifera

    Sponges lack true tissues, have porous bodies, and use choanocytes for filter feeding; sister group to all other animals.

  • How do ctenophores move and catch prey?

    Move using cilia rows; catch prey with sticky cells called colloblasts, unlike cnidarians' stinging cnidocytes.

  • Major body forms of cnidarians and their purposes

    Polyp (sessile, feeding/reproductive stage) and medusa (free-swimming, sexual reproduction stage).