Ras is a g-protein that is activated when a growth factor attaches to egfr. its activation results in the replacement of a gdp m
olecule with a gtp molecule, thus allowing a signal transduction pathway to be activated. considering the signal pathway illustrated on this page, what is one potential outcome of a mutation in the ras gene that leads to ras protein hyperactivity. be specific.
A mutation in Ras protein which will cause hyperactivity will eventually lead to cancer.
Explanation:
Ras protein was first discovered in Rous sarcoma virus (RSV) and it is a proto-oncogene product. In normal conditions, it plays an important role in cellular signalling but in case of gain of function/hyperactivity it gets converted into cellular oncogene. In several types of cancers a point mutation has been reported in Ras protein.
Just like G protein, it is also a GTPase switch protein but unlike G protein which is trimeric, it is monomeric. In the plasma membrane, it is attached with the help of lipids like prenyl or palmitoyl groups. During signal transduction pathway when it gets activated, it downstream activates MAPK pathway and causes gene expression but when it gets hyperactivated it causes over expression of genes leading to cancer.
The purpose of DNA replication is to produce two identical copies of a DNA molecule. This is essential for cell division during growth or repair of damaged tissues. DNA replication ensures that each new cell receives its own copy of the DNA.
The fluidity and the permeability of cell membrane must be maintained within a certain range for the cell to function properly.
The permeability of cell membrane depends on a number of factors, among them is the degree of saturation of fatty acids tails making up phospholipids.
Phospholipid tails can be saturated or unsaturated. Saturated tails have no double bonds and as a result have straight, unkinked tails, while unsaturated tails have double bonds and, as a result, have crooked, kinked tails.
Interactions between tails are maximized in the case of saturated tails, thus decreasing membrane fluidity and permeability, while unsaturated tails increases membrane fluidity.
