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Microbiology Exam 1 Key Concepts

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  • Cell theory

    Cell theory states that all living organisms are composed of cells, and all cells arise from pre-existing cells.

  • Germ theory of disease

    Germ theory proposes that microorganisms are the cause of many diseases.

  • Koch’s Postulates

    Koch’s Postulates are criteria to establish a causative relationship between a microbe and a disease.

  • 5 Basic types of microbes

    The five basic types of microbes are bacteria, archaea, fungi, protozoa, and viruses.

  • Eukaryote vs. prokaryote cell plans

    Eukaryotes have membrane-bound organelles and a nucleus; prokaryotes lack these structures.

  • How each cell type takes in nutrients

    Prokaryotes use passive diffusion, facilitated diffusion, active transport; eukaryotes use endocytosis and membrane transport.

  • Nuclear information of each cell type

    Prokaryotes have a nucleoid with circular DNA; eukaryotes have a membrane-bound nucleus with linear chromosomes.

  • Sterols vs. hopanoids

    Sterols stabilize eukaryotic membranes; hopanoids perform a similar role in bacterial membranes.

  • Cytoplasmic structures in each cell type

    Eukaryotes have organelles like mitochondria and ER; prokaryotes have ribosomes and sometimes inclusions but no membrane-bound organelles.

  • Cell division

    Prokaryotes divide by binary fission; eukaryotes divide by mitosis or meiosis.

  • Location of Electron Transport Chains

    In prokaryotes, ETCs are in the cytoplasmic membrane; in eukaryotes, they are in the inner mitochondrial membrane.

  • Major components of cell walls for each microbe type

    Bacterial walls contain peptidoglycan; fungi have chitin; algae have cellulose or other polysaccharides.

  • Flagella arrangements for prokaryotes vs. eukaryotes

    Prokaryotic flagella rotate; eukaryotic flagella have a 9+2 microtubule structure and whip back and forth.

  • 3 Domain Classification scheme

    The three domains are Bacteria, Archaea, and Eukarya, classified by rRNA sequences and cell structure.

  • Basic shapes of bacteria

    Bacteria shapes include cocci (spherical), bacilli (rod-shaped), and spirilla (spiral-shaped).

  • Cocci arrangements

    Cocci can be arranged as singles, pairs (diplococci), chains (streptococci), or clusters (staphylococci).

  • Passive diffusion, osmosis, facilitated diffusion, active transport

    Passive diffusion moves molecules down concentration gradients; osmosis is water diffusion; facilitated diffusion uses transport proteins; active transport requires energy.

  • Role of aquaporins

    Aquaporins are membrane proteins that facilitate rapid water transport across cell membranes.

  • Energy sources for active transport

    Active transport uses energy from ATP hydrolysis or proton motive force to move substances against gradients.

  • Uniporter, symporter, antiporter, ABC cassette

    Uniporters transport one molecule; symporters transport two molecules in the same direction; antiporters transport molecules in opposite directions; ABC transporters use ATP to transport substances.

  • Group translocation

    Group translocation chemically modifies a molecule during transport into the cell, commonly seen in bacteria.

  • Functions of cytoplasmic membrane

    The cytoplasmic membrane controls transport, energy generation, and acts as a barrier.

  • Binary fission and geometric progression

    Binary fission is bacterial cell division; populations grow exponentially following geometric progression.

  • Ways antibiotics affect bacteria

    Antibiotics target cell wall synthesis, protein synthesis, DNA replication, or metabolic pathways in bacteria.

  • Gram positive, gram negative, acid-fast

    Gram positive bacteria have thick peptidoglycan walls; gram negative have thin walls and outer membranes; acid-fast bacteria have waxy mycolic acids.

  • What is an endospore?

    An endospore is a dormant, resistant structure formed by some bacteria for survival under harsh conditions.

  • Organelles used in bacterial photosynthesis

    Bacteria use thylakoid membranes for photosynthesis; oxygenic photosynthesis produces oxygen, anoxygenic does not.

  • What is conjugation?

    Conjugation is bacterial DNA transfer through direct cell-to-cell contact using a pilus.

  • Eukaryote cell features

    Eukaryotes have membrane-bound organelles, a nucleus, cytoskeleton, and complex internal membranes.