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General Biology: A Tour of the Cell

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Termini in questo insieme (20)

  • What are the three important parameters of microscopy?
    Magnification: ratio of image size to real size; Resolution: clarity or minimum distance between points; Contrast: visible brightness differences.
  • What is the main limitation of light microscopes?
    Light microscopes cannot resolve internal cell anatomy well, especially organelles.
  • How do electron microscopes (EM) improve resolution compared to light microscopes?
    EMs use electron beams with shorter wavelengths, achieving resolution down to ~2 nm, much finer than light microscopes.
  • What is the difference between scanning electron microscopes (SEM) and transmission electron microscopes (TEM)?
    SEM studies surface structures; TEM studies internal cell structures using thin stained sections.
  • What is a key advantage of light microscopy over electron microscopy?
    Light microscopy can be used to observe live cells and dynamic processes.
  • What are the two main types of cells?
    Prokaryotic (Bacteria and Archaea) and Eukaryotic (Protists, fungi, animals, plants).
  • What is the key difference between prokaryotic and eukaryotic cells?
    Eukaryotic DNA is enclosed in a nucleus; prokaryotic DNA is in a nucleoid without a membrane.
  • What is the plasma membrane composed of?
    A double layer of phospholipids with embedded proteins and carbohydrates.
  • What is the function of the plasma membrane?
    Acts as a selective barrier regulating exchange of oxygen, nutrients, and waste.
  • What is the nucleus and its main function?
    An organelle containing most DNA; controls gene expression and DNA replication.
  • What is the nuclear envelope?
    A double membrane enclosing the nucleus with pores regulating exchange with cytoplasm.
  • What is the nuclear lamina?
    A protein filament network lining the nuclear envelope, maintaining nuclear shape.
  • What is chromatin?
    The uncondensed DNA-protein complex in the nucleus.
  • What is the nucleolus and its function?
    A dense region in the nucleus that synthesizes rRNA and assembles ribosomal subunits.
  • How do ribosomes function in protein synthesis?
    Ribosomes read mRNA and translate genetic code into polypeptides (proteins).
  • What are the two types of ribosomes?
    Free ribosomes in cytosol synthesize proteins for cytosol; bound ribosomes on ER synthesize proteins for membranes or export.
  • What is the cytoplasm in eukaryotic cells?
    The region between the nucleus and plasma membrane containing organelles.
  • Why are eukaryotic cells generally larger than prokaryotic cells?
    Eukaryotes have membrane-bound organelles and more complex internal structures.
  • What is the role of membrane proteins?
    They assist in transport, enzymatic activity, signal transduction, and cell recognition.
  • What is the function of mitochondria?
    Organelles that generate ATP through cellular respiration.