benefits of the nuclear double membrane Flashcards
Why is the nuclear membrane made of two phospholipid bilayers?
The double membrane of the nucleus helps prevent exposure of the hydrophobic core to water. It provides a barrier that prevents unwanted leakage of contents and maintains the integrity of the nucleus.
How does the nuclear membrane avoid damage or perforation?
The phospholipid bilayer naturally forms shapes like micelles or flattened cisternae to avoid exposed hydrophobic cores, which would otherwise attract water. Large holes are only formed in cases of catastrophic damage (e.g., haemolysis).
What is the function of nuclear pores in the double membrane?
Nuclear pores allow the transport of large molecules like mRNA, tRNA, and ribosomes between the nucleus and cytoplasm. The large size of these molecules requires larger pores than those found in typical channel proteins.
Why are nuclear pores larger than typical membrane channels?
The larger nuclear pores are necessary to accommodate the passage of large molecules such as RNA and ribosomes. The pores are made by integral proteins, and their size is controlled by proteins that regulate what passes through.
How does the nuclear membrane assist in cell division?
During mitosis and meiosis, the nuclear membrane breaks down to allow chromosomes to be moved to the poles of the cell. This breakdown is facilitated by the double membrane, which can vesiculate and form new membranes during the reformation process.
What role do vesicles play in the breakdown and reformation of the nuclear membrane?
During cell division, vesicles bud off from the nuclear membrane, progressively breaking it down. These vesicles then move to the sides of the cell and fuse together to form new nuclear membranes around the newly separated chromosomes.
How does the nuclear double membrane benefit protein transport into and out of the nucleus?
The double membrane allows for the formation of larger pores that are controlled by proteins, which regulate the selective transport of proteins and RNA between the nucleus and cytoplasm. This is critical for gene expression regulation.
