Which of the following statements is true of G proteins?Group of answer choicesThey become activated when bound to GTPThey become activated when bound to GDPThey become activated when they hydrolyse GDPThey become activated when they hydrolyse GTP

G proteins switch themselves off by...Group of answer choicesreleasing GDP and binding GTPhydrolysing GTP, forming GDPhydrolysing GDP, forming GTPreleasing GTP and binding GDP

Which of the following statements best describes an important feature of G protein activation?Group of answer choicesHydrolysis of GTP to GDP by the alpha subunit provides required energy for the activation of downstream signaling molecules.G proteins that interact with GPCRs are often referred to as monomeric.When ligand bound GPCRs interact with G proteins, they act as GEFs (guanine nucleotide exchange factors) leading to G protein activation.G proteins are equally activated by ATP or GTP.Neither G proteins nor GPCRs have lipid anchors, only downstream effector proteins do.

Which of the following statements applies to G proteins?Group of answer choicesG proteins do not use second messengers, but transmit signals directly into the nucleusG proteins are dimeric, composed of two different subunitsG proteins transmit a signal from the interior of the cell to the cell surfaceG proteins act to amplify a signal creating a cascade response in the cell

Which of the following statements about proteins is false?

Which of the following is NOT TRUE of enzymes?Group of answer choicesall enzymes are proteinsenzymes are changed in the reaction they performenzymes catalyze metabolic reactionsenzymes work on substratesenzymes lower activation energy of reactions