Pages - Menu

Friday, 18 November 2016

STPM Biology Structure of Cell and Organelle (Part 5)

Endoplasmic reticulum


Distribution:

  • Rough endoplasmic reticulum (RER) are usually attached to the nucleus. Smooth endoplasmic reticulum (SER) are dispersed in the cytoplasm.
  • Found in abundance in liver cells (detoxification center), pancreatic cells (secretes enzymes) and brain cells.
    endoplasmic reticulum
    RER, SER and Ribosomes


Structure:

  • Endoplasmic reticulum is a network of flattened sacs and tubules. Endoplasmic reticulum is surrounded by a membrane.
  • Rough endoplasmic reticulum (RER) is the network of flattened sacs bounded by a membrane. Robosomes are found on the surface of RER.
  • Smooth endoplasmic reticulum (SER) is a network of tubules. No ribosomes are present.
  • Endoplasmic reticulum is filled with fluid. This fluid contains carbohydrates, protein, lipids, cholesterols and steroids.


Functions:

  • Smooth endoplasmic retiulum (SER) synthesizes, secretes and stores lipid, steroids, choloesterols and carbohydrates.
  • SER is a main site for detoxification substances in cells, especially liver cells. Enzymes in SER catalyze the break down of a variety of poisons and toxic compounds.
  • Ribosomes on the rough endoplasmic reticulum (RER) manufacture proteins and enzymes.
  • Both endoplasmic reticulum also serve as an intracellular transport system.

No comments:

Post a Comment