Question

The growth factor was a signalling molecule that bound to a receptor. channel Okinase O G-protein contact-dependent Question 10 2 pts Which of the following best explains why dimerization of the kinase receptor in the absence of a growth factor could lead to cancer? The dimerization produces the growth factor, which can the signal for the cell to divide even if it was not supposed to. O Dimerization would cause the alpha subunit of a G-protein to become activated, leading to cell division when the cell is not supposed to. The dimerization would lead to destruction of the receptor and without the receptor the cell would grow uncontrolably The receptor would undergo phosphorylation which then activates the signal transduction pathway, causing the cell to divide even when there was no signal.

Answer 1

1) growth factors bind to the receptors on the membrane, these membrane proteins have intrinsic kinase activity, those receptors belong 2 large families of receptors serine-threonine kinase receptors, receptor tyrosine kinase.

so the answer is b) kinase.

2) the receptors of the growth factors ( both serine-threonine kinase receptors, receptor tyrosine kinase) dimerize upon the ligand binding, and then phosphorylate the cytoplasmic domains, then phosphorylate the signaling molecules, if the receptor dimerize without the ligand binding then signaling will occur even in the absence of the signaling molecule. so it results in the cell division ( growth factors signals the cell to divide) so the answer d) The receptor would undergo phosphorylation which then activates the signal transduction pathway, causing the cell to divide even when there was no signal.