Cell structure

shannon.bates
Mind Map by shannon.bates, updated more than 1 year ago
shannon.bates
Created by shannon.bates over 6 years ago
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Cell structure

Resource summary

Cell structure
  1. Nucleus
    1. Contains DNA
      1. DNA arranged into long thin threads known as chromosomes
        1. In most cells the chromosomes are arranged in homologous pairs
          1. Surrounded by nuclear envelope
            1. This has pores to allow communication between the nucleus and cytoplasm
            2. Plasma membrane
              1. Sea of phospholipids - arranged as a bilayer
                1. Intrinsic and extrinsic proteins float within the phospholipids
                  1. Selectively permeable barrier - controls movement of substances between the internal and external environments
                  2. Lysomes
                    1. Formed by the golgi apparatus
                      1. Contain digestive enzymes - proteases and lipases
                        1. Important to protect the cell from the effect of these enzymes before they are released at the cell surface membrane or into a phagocytic vesicle
                        2. Mitochondria
                          1. Mostly protein, but also contains some lipid, DNA and RNA
                            1. Power house of the cell
                              1. Energy is stored in high energy phosphate bonds of ATP
                                1. Mitochondria convert energy from the breakdown of glucose into adenosine triphosphate (ATP)
                                  1. Responsible for aerobic respiration
                                    1. Metabolic activity of a cell is related to the number of cristae (larger surface area) and mitochondria
                                    2. Ribosomes
                                      1. Small organelles often attached to the ER but also found in the cytoplasm
                                        1. Large (protein) and small (rRNA) subunits form the functional ribosome
                                          1. Subunits bind with mRNA in the cytoplasm
                                            1. This starts translation of mRNA for protein synthesis (assembly of amino acids into proteins
                                          2. Free ribosomes make proteins used in the cytoplasm. Responsible for proteins thatgo into solution in cytoplasm or form important cytoplasmic, structural elements
                                            1. Ribosomal ribonucleic acid (rRNA) are made in nucleus of cell
                                            2. Endoplasmic reticulum
                                              1. Rough ER
                                                1. Have ribosomes attached to the cytosolic side of their membrane
                                                  1. Found in cells that are making proteins for export (enzymes, hormones, structural proteins, antibodies) Thus, involved in protein synthesis
                                                    1. Modifies proteins by the addition of carbohydrates, removal of signal sequences
                                                      1. Phospholipid synthesis and assembly of polypeptides
                                                      2. Smooth ER
                                                        1. Have no ribosomes attached and often appear more tubular than the rough ER
                                                          1. Necessary for steroid synthesis, metabolism and detoxification, lipid synthesis
                                                            1. Numerous in the liver
                                                          2. Golgi apparatus
                                                            1. Stack of flattened sacs surrounded by membrane
                                                              1. Receives protein-filled vesicles from the rough ER (fuse with Golgi membrane)
                                                                1. Uses enzymes to modify these proteins (e.g. add a sugar chain, making glycoprotein)
                                                                  1. Adds directions for destination of protein package - vesicles that leave Golgi apparatus move to different locations in cell or proceed to plasma membrane for secretion
                                                                    1. Involved in processing, packaging, and secretion
                                                                      1. Other vesicles that leave Golgi apparatus are lysosomes
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