Lecture Four Flashcards
What is the endomembrane system?
Group of organelles involved in sorting and transporting vesicles and vacuoles (bulk transport)
What is the structural and functional differences between sER and rER?
Smooth ER has no ribosomes attached to it, whereas rough ER does. sER metabolisms carbohydrates, synthesises lipids, detoxifies, stores calcium ions. rER synthesises proteins.
What is the inside fluid filled parts of ER called?
Lumen
This part can be compared to the website Amazon.
Golgi apparatus
The golgi apparatus has two sides called what? What’s the difference?
Cis and trans. Cis receives vesicles, trans pushes them out.
What is a lysosome? What does it do? What is its structure? What happens if it breaks?
Is a digestive/metabolizing organelle. It will break down polymers into monomers to be used for energy. It has a plasma membrane, and contains acidic fluid with enzymes. If one broke, it would be unusable due to the enzymes needing the acidic conditions to work. If many broke, it would start making the cell’s cytosol acidic, which could cause the cell to digest itself.
What is a vacuole?
A vacuole is a large vesicle, and is used to transport solutes.
Describe the journey of an ER protein that needs a structural change before performing its function in the ER.
mRNA is synthesised in the nucleus, and then passes out the nuclear pore into the cytoplasm. The mRNA then attaches to the ER, creating protein that then goes into the lumen. The protein will then undergo changes in the lumen, and will then be transported out of the ER in a vesicle to the cis side of the golgi apparatus, putting proteins into the golgi apparatus using exocytosis. The golgi apparatus will then change and modify the protein, and will package it into a vesicle with markers on it to ensure it goes to the ER. The vesicle then leaves the golgi apparatus on the trans side, and the protein will go back to the ER to perform its function.
What is exocytosis? What is an example of this?
A vesicle will fuse with the plasma membrane for where it wants to go, causing the contents of the vesicle to spill out to the other side. An example is insulin produced in the pancreas, where exocytosis is used to get it into the extracellular fluid.
What is pinocytosis?
Pinocytosis is when the cell membrane concaves and fills with extracellular fluid. The cell membrane will then pinch off, creating a vesicle inside of the cell.
What is receptor-mediated endocytosis?
This is endocytosis, and is used when a certain substance is wanted, particularly when it is at a lower concentration in the extracellular fluid. The cell membrane will have receptors on the extracellular side, and clathrin molecules (proteins) on the intracellular side. The ligands (wanted molecule) bond to the receptors, and the cell will concave and pinch off, allowing the vesicle to be inside the cell. The clathrin will then leave the membrane of the vesicle and go back to the plasma membrane. An endosome (transport vesicle) will then fuse with the vesicle, and the receptors and ligands will go to opposite sides. The cell will then split, and the endosome will take the receptors back to the plasma membrane. A lysosome will then fuse with the vesicle, digesting its contents.
What is phagocytosis?
Phagocytosis is another form of endocytosis. A particle will be engulfed by the cell, and the plasma membrane then pinches off, resulting in the vesicle being on the inside of the cell. A lysosome will then fuse with the vesicle, digesting it.
What is glycosylation?
Adding carbs to proteins
