1. Plasma Membrane
    Structure: Double layer of lipids; embedded with proteins.

    Function: An external cell barrier; acts in transport of substances in/out of cell.
  2. Cytoplasm
    • Structure: Part of cell that lies internal to plasma membrane, external to nucleus. Jelly like.
    • Water, ions and enzymes.
    • Function: The cytoplasm plays an important role in a cell, serving as a
    • "molecular soup" in which the organelles are suspended and
    • held together by a fatty membrane.
  3. Ribosomes
    • Structure: Dense particles of two sub units; each composed of ribosomal RNA and protein; free or
    • attached to rough ER.
    • Function: The sites of protein synthesis.
  4. Rough Endoplasmic Reticulum
    • Structure: Membrane system enclosing a cavity, the cisterna, and coiling through the cytoplasm;
    • externally studded with ribosomes.
    • Function: Makes proteins that are secreted from the cell; makes the cell’s membranes.
  5. Smooth Endoplasmic Reticulum
    • Structure: Membranous system of sacs and tubules; free of ribosomes.
    • Function: Site of lipid and steroid synthesis, lipid metabolism and drug detoxification.
  6. Golgi Apparatus
    • Structure: A stack of smooth membrane sacs close to the nucleus.
    • Function: Packages, modifies, and secretes proteins for secretion from the cell, inclusion in
    • lysosomes
  7. Mitochondria
    • Structure: Rod-like, double membrane structures; inner membrane folded into projections called
    • cristae.
    • Function: Site of ATP synthesis; powerhouse of the cell.
  8. Lysosomes
    • Structure: Membranous sacs containing acid hydrolases.
    • Function: Sites of intracellular digestion.
  9. Peroxisomes:
    • Structure: Membranous sacs of oxidase enzymes
    • Function: The enzymes detoxify a number of toxic substances; the most important enzyme,
    • catalase, breaks down hydrogen peroxide
  10. Microtubules
    • Structure: Cylindrical structures made of tubulin proteins
    • Function: Support the cell and give it shape. Involved in intracellular movements, form
    • centrioles.
  11. Centrioles
    • Structure: Paired cylindrical bodies, each composed of nine triplets of microtubules.
    • Function: Organize a microtubule network during mitosis to form the spindle and asters; form the
    • bases of cilia and flagella.
  12. Nucleus:
    • Structure: Surrounded by the nuclear envelope; contains fluid nucleoplasm, nucleoli and chromatin.
    • Function: Control center of the cell; responsible for transmitting genetic information and
    • providing the instructions for protein synthesis.
  13. Nucleoli
    • Structure: Dense spherical (non-membrane bounded) bodies
    • Function: Site of ribosome subunit manufacture.
  14. Chromatin:
    • Structure: Granular, thread-like material composed of DNA and hystone proteins.
    • Function: DNA constitutes the genes.
Card Set
Cells, organelles function and structure.