formation of mucus

• mucus is a glycoprotein secreted by goblet cells which line the respiratory airways. its job is to trap microbes and dust present in air which is inhaled so protecting the lungs from infection
• the gene which codes for mucus can be found on a chromosome inside the nucleus. the instructions in the gene get copied into a MRNA so they can leave the nucleus. The MRNA passes through a nuclear pore in the nuclear envelope and enters the cytoplasm
• the MRNA molecule attaches to a ribosome on the Rough Endoplasmic Reticulum. the ribosome uses the instructions present in the MRNA to make the protein. the protein enters the RER and travels through it
• The protein leaves the RER by being enclosed in a vesicle. The vesicle travels through the cytoplasm and fuses with the Golgi Body
• at the Golgi body the protein is modified and a carbohydrate chain is added to form a glycoprotein. energy is needed in the form of ATP which is provided by the mitochondria
• the glycoprotein is released from the Golgi body in a secretory vesicle. the secretory vesicle moves through the cytoplasm and fuses with the plasma membrane to release the glycoprotein (mucus) to the outside of the cell. this is called exocytosis and needs ATP from the mitochondria