Cell Signalling: Ion Channels and Transport

What type of ion is Ca2+ classified as in the context of cell signalling?

A pH-regulating ion
A ubiquitous signalling ion (correct)
A ubiquitous signalling molecule
A proton gradient ion

What is the main function of ion gradients in cell signalling?

To transport molecules across the phospholipid bilayer (correct)
To regulate pH levels
To synthesize proteins
To generate ATP

What is the mechanism by which ion gradients are generated?

Facilitated diffusion
Osmosis
Passive transport
Active transport (correct)

What is the role of phosphorylation in ion transport?

To provide energy for conformational change (D) Signup and view all the answers

What is the stoichiometry of the Na+/K+ pump?

5 (B) Signup and view all the answers

Which protein generates Ca2+ concentration gradients across intracellular stores?

SERCA (B) Signup and view all the answers

What type of transport can pump ions against their concentration gradient?

Active transport (C) Signup and view all the answers

What is the purpose of ion gradients in cell signalling?

To drive secondary transport (A) Signup and view all the answers

What is the function of the Na+/Ca2+ exchanger?

To pump Ca2+ ions out of the cell along their concentration gradient (B) Signup and view all the answers

What is the tetrameric structure composed of in voltage-gated ion channels?

S1, S5, S6, and S7 domains (A) Signup and view all the answers

What is the function of the selectivity filter in K+ channels?

To stabilize dehydrated K+ ions (C) Signup and view all the answers

What is the function of the S1 domain in voltage-gated ion channels?

To sense voltage changes (B) Signup and view all the answers

What is the function of the S4 region in voltage-gated ion channels?

To sense voltage changes (A) Signup and view all the answers

What is the equilibrium potential in the cell at T=eq?

V = -2 (A) Signup and view all the answers

What is the function of the fixed anions in the cell?

To attract K+ ions into the cell (C) Signup and view all the answers

What is the result of the equilibrium between the electrical and chemical gradients?

The electrical and chemical gradients cancel out (B) Signup and view all the answers

When a signalling molecule binds, what happens to the GDP bound to the G-protein?

It is replaced by GTP (D) Signup and view all the answers

What is the role of Guanine Nucleotide Exchange Factors (GEFs) in G-protein signalling?

They promote the GDP to GTP transition (B) Signup and view all the answers

What is the role of the βγ subunit in G-protein signalling?

It dissociates from the α subunit when GTP binds (C) Signup and view all the answers

How does the αs subunit regulate adenylyl cyclase?

It activates adenylyl cyclase (A) Signup and view all the answers

What is the ultimate outcome of the activation of nAChRs at the neuromuscular junction?

Depolarization of muscle cells (B) Signup and view all the answers

What is the role of protein kinase A in cAMP signalling?

It phosphorylates and activates the substrate (C) Signup and view all the answers

What is the common structure shared by GPCRs?

7 transmembrane regions (A) Signup and view all the answers

What terminates cAMP signals?

Phosphodiesterase (D) Signup and view all the answers

What is the role of GTP in the activation of GPCRs?

It replaces GDP, activating the receptor (B) Signup and view all the answers

What type of ion channels respond to released neurotransmitters?

Ligand-gated ion channels (A) Signup and view all the answers

What is the effect of adrenaline on the heart through the cAMP pathway?

It increases the force of contraction (C) Signup and view all the answers

What is the role of IP3 in the IP3 and DAG pathway?

It activates intracellular ligand-gated ion channels (D) Signup and view all the answers

What is the result of signalling through inhibitory synapses?

Dampened electrical signalling (D) Signup and view all the answers

What is the purpose of the pore domain in inotropic glutamate receptors?

It forms the channel through which ions flow (C) Signup and view all the answers

What is the function of ATP in the activation of GPCRs?

It provides the energy for receptor activation (D) Signup and view all the answers

What is the result of Ca2+ release from the sarcoplasmic reticulum in muscle cells?

Contraction of the muscle (A) Signup and view all the answers

What is the primary function of IP3 receptors in muscle contraction?

To release calcium (C) Signup and view all the answers

What is the effect of Ca2+ binding on calmodulin?

Induces conformational changes and binding to target proteins (D) Signup and view all the answers

What is the role of the grey subunit in Cam Kinase activation?

It is associated with calmodulin to activate Cam Kinase (B) Signup and view all the answers

What is the function of PMCA and SERCA in Ca2+ signalling?

To remove Ca2+ from cells (D) Signup and view all the answers

What is the role of Na+/Ca2+ exchangers in Ca2+ signalling?

To drive calcium out of the cell (A) Signup and view all the answers

What is the requirement for protein kinase C (PKC) activation?

Both DAG and Ca2+ (A) Signup and view all the answers

What is the role of receptor tyrosine kinases in cell signalling?

To dimerize and autophosphorylate upon activation (B) Signup and view all the answers

What is the role of Grb-2 in MAP kinase signalling?

To recruit Sos (D) Signup and view all the answers