cells

• cell surface membrane is made out of phospholipids , arranged in a lipid bilayer in which protiens are embedded
• cell surface membrane acts as a boundary between the cell cytoplasm and extracellular enviroment
• cell surface membrane is partially permeable
• cell surface membrane regulates the movement of molcules in and out of the cell , preventing charged ions and polar molecules from diffusing across the membrane
• nuclear envelope is a double membrane surrounding the nucleus whereby the outer membrane is continous with RER , and smooth in the inner membrane allowing compartmentalization of eukaryotic DNA where DNA can carry out its functions without being affected by the process
• structure of the nucleur envelope has numerous nucleur pores each being 40-100mm
• function of the nucleur envelope controls the export of mRNA out of the nucleus into cytoplasm and import of ribosomal proteins into the nucleus
• function of the nucleur envelope prevents DNA from being transported out of the cell
• nucleolus is tiny , rounded , darkly stained structure
• function of the nucleolus is the site where rRNA are synthesized via transcription of rRNA gene
• function of the nucleolus is the site where ribosomal subunits are assembled by associating rRNA and ribosomal protiens
• endoplasmic reticulum consists of extensive networks of folded membranes that are interconnected to the nucleur envelope
• ER membrane enclosed to form the cisternae / lumen of the ER
• RER cisternae is usually flattened
• Structure of RER has ribosomes bound to the membrane of the endoplasmic reticulum giving the endoplasmic reticulum a rough appearance
• Struture of RER has presense of various protiens embedded
• Function

  RER has membrane bounded reibosomes that are the site of synthesis of proteins for transport to other parts of the cells via vesicles
• Function of RER

  Channel protiens provide binding sites for ribosomes to dock and synthesise polypeptides directly into the cisternae
• Function of RER has enzymes involved in glycosylation of proteins to form glycoproteins
• Structure of SER

  cisternae is more tubular
• Structure of SER

  SER has no ribosomes bound to the membrane of the endoplasmic reticulum
• Function of SER

  production and transportation of membrane phospholipids , cellular lipids and steroid hormones such as testerone and oestrogen
• Function of SER

  detoxification of drugs and liver cells via chemical modification
• Function of SER

  storage of calcium ions in muscle cells for contraction
• Function of SER

  helps the liver cells to carry out metabolism of carbohydrates
• Structure of golgi apparatus

  flattened membrane bound sacs called cisternae
• structure of golgi apparatus

  consists of cis face nearest to the nucleus
• structure of golgi apparatus

  consists of trans face nearest to cell membrane
• Function of golgi apparatus

  chemically modifies protien and lipids via glycosylation
• function of golgi apparatus

  addition of molecular identification tags
• function of golgi appratus

  sorting and packaging golgi products and targeting them for various parts because of their identification tag
• function of golgi apparatus

  forms lysosomes which are vesicles carrying hydolytic enzymes
• function of golgi apparatus

  replaces cell surface membrane
• function of golgi apparatus

  synthesis of plant polysaccharides
• structure of a Typical Bacteria cell

  peptidoglycan cell wall

  1. protect cell
  2. maintain cell shape
  3. made out of carbohydrate-protein complex
• Structure of Typical Bacteria cell

  • Circular DNA

  involved in cell control

  involved in reproduction
• Structure of Typical Bacteria cell

  70s ribosomes for protein synthesis