IMMS Extra

Question 1

Types of membrane carrier proteins

Answer 1

Uniport
Symport
Antiport

Question 2

Example of a carrier protein (passive transport)

Answer 2

GLUT-4, uptake of glucose into cells via facilitated diffusion. Expression of GLIT-4 upregulated by insulin

Question 3

Example of carrier protein (passive transport) in disease

Answer 3

GLUT-1- present in many cells including brain: transports glucose across blood-brain barrier.
GLUT- deficiency syndrome, mutations in GLUT-1 gene. less functional GLUT-1-less glucose to brain.
Symptoms- seizures, developmental delay

Question 4

Example of disease in primary active transport protein

Answer 4

ATP7B Ca2+ channel in liver, transports excess copper into bile.
Wilson’s disease:
-mutation in ATP7B gene
-Deposition of copper in liver and other tissues etc

Question 5

Example of disease in secondary active transport

Answer 5

SGLT-1: Transports glucose (or galactose) into cells using Na+ ions.
Mutation in SGLT-1 :
Glucose-galactose malabsorption

Question 6

Peptide vs steroid hormones

Answer 6

Peptide stores in cells and released when needed. Receptor on extracellular surface of cells, can freely move through blood.

Steroid, produced from cholesterol, require carrier proteins to move through blood. Intracellular receptor

Question 7

Types of cel receptors

Answer 7

• Ligand gated ion channels (e.g cholinergic receptors)
• GPCR (e.g alpha/beta adtenergic receptors)
• Enzyme linked receptors (e.g insulin receptor)
• intracellular receptors (e.g steroid receptor)

Question 8

GPRCR in disease

Answer 8

Cholera toxin
In intestinal cells, modifies alpha subunit of G protein. Over active G alpha over activates adenylate Cyclase- overproduction of cAMP- stimulation of several transporter proteins- massive secretion of ions and water into gut lumen- dehydration, diarrhoea

Question 9

Cystic fibrosis

Answer 9

Mutation in CFTR chloride ion channel:

-sticky, viscous mucous due to abnormal CFTR

Question 10

Drugs that target mem proteins

Answer 10

Cardiac glycosides:
Act on Na/K pump in cardiac muscle cells

Proton pump inhibitors:
Act in H/K ATPase in gastric parietal cells

Loop and thiazide diuretics

Question 11

Types of endocytosis

Answer 11

• phagocytosis
• pinocytosis (non-specific small molecules)
• receptor mediated endocytosis (specific)

Question 12

Example of a fatty acid

Answer 12

Linoleic acid (18 carbons)

Question 13

Oedema and types of Oedema

Answer 13

Excess water in interstitial space

Inflammatory
Venous
Lymphatic
Hypoalbuminaemic

Question 14

Serous effusion

Answer 14

Excess water in a body cavity - e.g Pleural effusion

Question 15

Pleural effusion

Answer 15

Excess fluid in pleural space (normally contains ~10ml)

Transudate-fluid moves into pleural cavity through intact blood vessel, typically due to low plasma content which causes low oncotic pressure

Exudate- Fluid moves into pleural cavity through ‘leaky vessels’ typically as a result of inflammation/infection

Question 16

Tight junction-seal epithelial cells
Adherens junction- join actin bundles between neighbouring cells
Desmosomes- joint intermediate filaments between neighbouring cells
Hemidesmosomes-Anchor intermediate filaments to basal Lamina (part of BM)
Gap junctions- Allow small molecules and electival signals through

Answer 16

A