C2 Membrane proteins and transmembrane transport

Question 1

What are G protein coupled receptors?

Answer 1

Extracellular loops and cytostolic loops

Question 2

What is the ligand that attaches to CCK2 receptors?

Answer 2

Gastrin peptide

Question 3

Name the three types of recpetors (GPCR)?

Answer 3

1. G protein coupled receptors
2. Receptor Tyrosine Kinase - RTK (58)
3. Nuclear receptors (48)

Question 4

Name the three kinds of membrane protein

Answer 4

1. Integral membrane proteins
2. Lipid-modified membrane proteins
3. Accessory membrane proteins

Question 5

Describe the two types of ion channel.

Answer 5

Voltage gated channel
Ligand gated channel (sometimes called a receptor)
Both highly selective, allow diffusion down an electrochemical gradient

Question 6

Three gates on ion channels

Answer 6

ATP gated (three sub units)
Voltage gated (K+ channel, four subunits)
L-glutamine gated (Cl- channel, five subunits)

Question 7

Describe the selectivity of a solute transporter?

Answer 7

Highly selective as to which molecules it will transport down a gradient across a membrane.

Question 8

Three types of solute transporter?

Answer 8

1/ Uniporter - conformational change, works like a door flap
2/ Symporter - same direction
3/ Antiporter - molecules move in opposite directions(one moves down gradient providing energy for the other molecule to move against the gradient)

Question 9

What is the 3rd class of transport across membrane?

Answer 9

Less efficient = ATP-dependent transport

1. ATP-dependent ion pumps (transport against the gradient, energy provided by hydrolysis of ATP
2. ABC Transporter

Question 10

How can membrane proteins be classified?

Answer 10

Architectural or functional

Question 11

Examples of architectural proteins?

Answer 11

Integral membrane proteins, lipid-modified membrane proteins, peripheral (accesory) membrane proteins

Question 12

Examples of functional proteins?

Answer 12

Receptors, signalling, transmembrane transport, attachment, migration, other roles e.g. protection