Endomembrane system

• What does the endomembrane system consist of.

  
  

  • Nuclear membrane
  • Golgi apparatus
  • Endoplasmic Reticulum
  • Lysosomes
• What are the main functions of the Smooth endoplasmic reticulum.

  Manufacturing of phospholipids, fats and steroids.

  Carbohydrate metabolism.

  Glycogenolysis in hepatocytes.

  Detoxification of lipid-soluble drugs.
• Define Glycosylation

  Addition of sugars or oligosaccharides to proteins to form glycoproteins.
• What are the main roles of the Golgi apparatus

  • Modifies and sorts proteins
  • Controls the flow of proteins from RER to destination
• What are lysosomal storage diseases

  The accumulation of partially degraded metabolites due to a defective lysozyme. This results in an enlarged lysosome.
• What is an example of a Lysosomal storage disease

  • Tay-Sachs disease
• Where is the sarcoplasmic reticulum found

  Muscle cells
• What is the sarcoplasmic reticulum.

  A network of tubular sacs.
• What is the role of the sarcoplasmic reticulum

  Regulation of muscle contractions by signal transduction and intracellular calcium levels.
• What is the role of the rough endoplasmic reticulum

  Protein synthesis.
• Why is the Rough endoplasmic reticulum called rough

  It has ribosomes attached
• What are the foldings in the endoplasmic reticulum called

  Cisternae
• What are the classes of proteins synthesised in the RER

  • Secreted proteins
  • Glycosylated proteins
  • Lysozymes
  • Membrane proteins
• How are proteins moved from the RER to the Golgi apparatus.

  Vesicles.
• what is the trans face of the Golgi apparatus.

  The side which releases proteins
• What is the cis face of the Golgi apparatus.

  The side which receives proteins.
• What are lysosomes.

  Vesicular structures containing enzymes.
• What pH are lysozymes activated at.

  Acidic.
• What type of enzymes are lysozymes.

  Hydrolytic.
• What are primary lysosomes.

  Lysosomes which originate from the trans face of the Golgi.
• What is a secondary lysosome.

  A vesicle formed by the fusion of a primary lysosome and endosome.
• Describe how a lysosome degrades a pathogen

  • Pathogen engulfed in a phagosome
  • Primary lysosome fuses with phagosome [Secondary lysosome]
  • Hydrogen ions pumped into secondary lysosome
  • Low pH activates lysozymes
• What are the processes that a lysosome carries out

  • Phagocytosis
  • Autolysis during apoptosis
  • Autophagy
• What is autophagy

  Recycling of worn out organelles.