Which is common feature shared between the GG-subunit of a G-protein complex and the c-ras protein? Select one: A. intrinsic GTPase activity
B. membrane associated protein
C. signal transduction
D. All of these
E. None of these

C. signal transduction

Explanation:

The GTPase activity is the ability to hydrolyze guanine triphosphate (GTP) to guanine diphosphate (GDP) and thus release chemical energy. The G-proteins are heterotrimeric protein complexes composed by alpha, beta and gamma (GG) subunits that form a complex located within the cell which is activated by protein-coupled receptors (GPCRs) localized in the cell membrane. The alpha subunit of heterotrimeric G proteins shares homology with the middle region of the c-ras protein, which is responsible for its GTPase activity. The c-ras protein contains a GTP binding motif that functions in mediating signal transduction pathways, which is attached to the cell membrane. When c-ras is inactive, it is bound to GDP, while c-ras is active when bound to GTP.

the sugar-phosphate backbone forms the structural framework of nucleic acids, including dna and rna. this backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule.

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.