Researchers identified the cellular defect behind cystic fibrosis in 1989. In this disorder, lung and pancreas cells trap salt within cells. The salty cellular interiors draw moisture in from surrounding tissue, drying out the mucus until it is so sticky that it clogs organs. Several new treatments, including a healthy gene introduced into the lungs in a nasal spray, target the illness at the cellular source. Compare the inside of cystic fibrosis affected cells to normal, surrounding tissue.
Are these cells hypertonic, hypotonic, or isotonic to their surroundings?
What organelle or organelles may be impacted by cystic fibrosis?
Explain your answer.
CF affects a cell protein called CFTR (cystic fibrosis transmembrane regulator). CFTR controls the flow of water and certain salts in and out of the body's cells. As the movement of salt and water in and out of cells is changed, the mucus that many cells normally make gets thicker.
In most kids with cystic fibrosis, the CFTR protein gets stuck inside the cells in a cell organelle known as the endoplasmic reticulum—a convoluted membranous sac within the cell where the synthesis of proteins like CFTR and other vital cell functions take place.
Cystic fibrosis (CF) is a genetic disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. This gene provides instructions for making the CFTR protein, which regulates the movement of salt in and out of cells.
Here's what causes CF:
Michael was a pleasant, happy infant who seemed to be developing normally until about six months of age. Able to roll over and sit for a few seconds, he suddenly seemed to lose those abilities. Soon, he no longer turned and smiled at his mother's voice, as he had before, and he did not seem as interested in his mobile as he once was. Concerned about Michael's reversals in development, his anxious parents took him to the doctor. It took exams by several specialists to diagnose Michael's Tay-Sachs disease, because, thanks to screening programs in the population groups known to have this inherited illness, fewer than ten new cases appear each year. Tay-Sachs patients are not able to break down fatty waste material that builds up on nerve cells. His nervous system would continue to fail, and he would be paralyzed and unable to see or hear by the time he died, before the age of four.
What organelle or organelles are likely responsible for Tay-Sachs disease?
Explain your answer.
The organelle primarily affected in Tay-Sachs disease is the lysosome.
Explanation: Tay-Sachs disease is classified as a lysosomal storage disorder because it arises from a deficiency in a lysosomal enzyme called beta-hexosaminidase A, which leads to the buildup of a specific lipid (GM2 ganglioside) within the lysosome.
Key points about Tay-Sachs and lysosomes:
Pompe disease is a rare (estimated at 1 in every 40,000 births), inherited and often fatal disorder that disables the heart and skeletal muscles. Patients with Pompe disorder are not able to break down large macromolecules such as glycogen into smaller molecules like glucose. This leads to increased muscle weakness and a lack of the monomers needed for cellular respiration.
What organelle or organelles are likely responsible for Pompe disease?
Explain your answer.
Pompe disease is a rare, fatal neuromuscular disorder that occurs when the body lacks the enzyme acid alpha-glucosidase (GAA). GAA breaks down glycogen into glucose, a simpler sugar that is the main energy source for most cells. When GAA is deficient, glycogen builds up in the lysosomes of cells throughout the body, particularly in the heart and skeletal muscles. This buildup damages organs and tissues, leading to the symptoms of Pompe disease.
What cell structure is defective in Pompe disease?
Mutations in the GAA gene cause Pompe disease. The GAA gene provides instructions for producing an enzyme called acid alpha-glucosidase (also known as acid maltase). This enzyme is active in lysosomes , which are structures that serve as recycling centers within cells.
Choose one of the disorders from the diagram above and research it. What are the symptoms? Connect it to the defective organelle
Diseases for Organelle Research