Which of the following are true for an element?

(i) Atomic number = number of protons + number of electrons

(ii) Mass number = number of protons + number of neutrons

(iii) Atomic number = number of protons = number of neutrons

(iv) Atomic number = number of protons = number of electrons

(a) (i) and (ii)

(b) (i) and (iii)

(c) (ii) and (iii)

(d) (ii) and (iv)

TLS Online TPP Program

#Id: 9078

#Unit 4. Cell Communication and Cell Signaling

GRK–β-arrestin pathway, suppress signaling by GPCRs, actually functions as a switch, turning off signaling by G proteins and turning on other signaling pathways.

TLS Online TPP Program

#Id: 9079

#Unit 4. Cell Communication and Cell Signaling

Muscarinic acetylcholine receptors coupled to a Gαi protein & found in cardiac muscles. 

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#Id: 9080

#Unit 4. Cell Communication and Cell Signaling

Binding of acetylcholine triggers the opening of an associated K+ channel  in the plasma membrane via the Gβγ subunit of a Gi protein

TLS Online TPP Program

#Id: 9081

#Unit 4. Cell Communication and Cell Signaling

The increase in K+ permeability hyperpolarizes the membrane, which reduces the frequency of heart muscle contraction.

TLS Online TPP Program

#Id: 9082

#Unit 4. Cell Communication and Cell Signaling

TLS Online TPP Program

#Id: 9083

#Unit 4. Cell Communication and Cell Signaling

Cholera toxin, secreted by Vibrio cholerae in the intestine of an infected person, is a heterodimeric protein (AB).