Forms of the ras protein found in tumors usually cause which of the following?
a) dna replication to stop
b) dna replication to be hyperactive
c) cell-to-cell adhesion to be nonfunctional
d) cell division to cease
e) growth factor signaling to be hyperactive

The correct answer is option E, that is, growth factor signaling to be hyperactive.

Explanation:

Ras genes encode proteins, which can result in cancer when mutated. All the Ras proteins are GTPases that function as molecular switches in the cell, monitoring signaling pathways and other associations. Ras proteins are generally monitored accurately by the factors, which switch off the GTPases activity.  

Ras GTPase family proteins perform various roles comprising migration, cell cycle progression, growth, apoptosis, and senescence. When the function of Ras is not monitored appropriately, hyper-proliferation can take place leading to cancer and developmental disorders.  

These changes result in constitutive activation of Ras, signifying that the gene is always switched on and there is the overproduction of the protein. This also enhances GTP binding, resulting in overactivity.  

the tricuspid valve is present between right atrium and right ventricle