Membrane protein function

Question 1

components of signal transduction

Answer 1

1. biding of signalling molecule to a receptor following a physiological stimulus
2. reception of the message by an integral membrane protein (transmitting signal across membrane
3. relaying primary message to the cell interior by the generation of an intracellular secondary messenger (release of hormone)
4. amplification and transduction (transmittance)
5. response then terminates the signal cascade

Question 2

G-Protein coupled Receptors (GPCRs)

Answer 2

contain 7 transmembrane segments

Question 3

what is key for GPCR specificity

Answer 3

binding to specific functional groups and dissociation constant (Kd) value.

lower Kd value means tighter binding

Question 4

what influences binding specificity

Answer 4

non-covalent interactions with amino acid side chains and functional groups

Question 5

what creates binding sites for hormones

Answer 5

amino acid side chains sticking out

Question 6

enzyme-linked receptors

Answer 6

contain a single transmembrane segment that may contain homodimers

activation leads to autophosphorylation or phosphorylation by tyrosine kinase

Question 7

example of enzyme-linked receptor

Answer 7

insulin

Question 8

phospholipid mediated signaling

Answer 8

phospholipases hydrolyze phospholipids to produce 2nd messengers to release calcium from ER

Question 9

why is membrane transport important

Answer 9

for nutrient intake and outtake

Question 10

important features of ion channels

Answer 10

selectivity
rapid conductance of ions
can be gated due to stimuli

Question 11

what generates the energy needed to push molecules against its gradient in primary active transport?

Answer 11

ATP breakdown

Question 12

what is the significance of conformational changes in terms of transport

Answer 12

it is important for signaling and acts as a regulation of activity of membrane proteins and enzymes