IMMS Extra Flashcards
Types of membrane carrier proteins
Uniport
Symport
Antiport
Example of a carrier protein (passive transport)
GLUT-4, uptake of glucose into cells via facilitated diffusion. Expression of GLIT-4 upregulated by insulin
Example of carrier protein (passive transport) in disease
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
Example of disease in primary active transport protein
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
Example of disease in secondary active transport
SGLT-1: Transports glucose (or galactose) into cells using Na+ ions.
Mutation in SGLT-1 :
Glucose-galactose malabsorption
Peptide vs steroid hormones
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
Types of cel receptors
- 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)
GPRCR in disease
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
Cystic fibrosis
Mutation in CFTR chloride ion channel:
-sticky, viscous mucous due to abnormal CFTR
Drugs that target mem proteins
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
Types of endocytosis
- phagocytosis
- pinocytosis (non-specific small molecules)
- receptor mediated endocytosis (specific)
Example of a fatty acid
Linoleic acid (18 carbons)
Oedema and types of Oedema
Excess water in interstitial space
Inflammatory
Venous
Lymphatic
Hypoalbuminaemic
Serous effusion
Excess water in a body cavity - e.g Pleural effusion
Pleural effusion
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