FoM:L6 - Membrane Transport

Question 1

What is an ion?

Answer 1

atoms or molecules with a net electrical charge
defined according to charge or valency

Question 2

What are the 3 main types of passive transport?

Answer 2

• diffusion and facilitated diffusion
• filtration
• osmosis

Question 3

What is filtration?

Answer 3

• water and solute moving across cell membrane due to HP generated by CVS
• e.g. filtration of plasma in Bowman’s capsule

Question 4

What are the characteristics of channels and carriers?

Answer 4

• relatively specific
• saturation is possible
• [transporters] impacts rate
• faster rate than simple

Question 5

give 3 examples of health impacts involving channel/carrier proteins

Answer 5

• Myasthenia gravis: NMJ channelopathy
• Long QT syndrome: Na+-K+ channels, arrythmias
• Neonatal diabetes mellitus - K ATP channel

Question 6

What are ATPases?

Answer 6

• class of enzymes
• energy released used to drive reactions
• integral = transmembrane

Question 7

What is primary active transport?

Answer 7

• uses ATP, against conc gradient
• e.g. Na+-K+ pump
• gradients store potential energy, energy is released when molecules diffuse down gradient

Question 8

What is secondary active transport?

Answer 8

• uses gradients
• symports (cotransport) and antiport (exchangers)

Question 9

How is movement controlled?

Answer 9

• diffusion: controlled by gradient
• symports/antiports require companion molecules
• gating mechanisms (ligand and voltage-gated)

Question 10

What are ligand gated channels?

Answer 10

• opens when chemical/ligand binds to channel/receptor