L.7 II Membrane Receptors Flashcards Preview

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Flashcards in L.7 II Membrane Receptors Deck (12)
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What are the 3 types of passive Transport

1. Simple diffusion

2. Facilitated diffusion

3. Osmosis



Explain Simple diffusion

No transported Required

small non-polar, lipid-soluble

high to low concentrations



Explain Facilitated diffusion 

Uses transporters to move impermeable solutes across the cell membrane 


Explain Osmosis

The movement/diffusion of water from high to low concentration of (h2o)


Explain active transport and it's two forms

Requires energy from ATP or an existing favorable gradient.

1. Primary

2. Secondary ( antiport and symport)



Differentiate Endocytosis 

exocytosis, pinocytosis, and phagocytosis 

Endocytosis engulfing material into cell

Exocytosis Releasing material out of cell

Pinocytosis: solutes and liquid into vessicles endo

Phago: bacteria ingestion, larger molecules, solid. 



How is the membrane potential maintained?

By the sodium potassium ATPASE pump and K+  Leak channels

3 Na out and 2 Na in

More Na outside, total one + charge to outside in one round. 


Nerst Equation 

E = Electrical potential created by one ion

E = RT/zf   ln (ion) outside / (ion) inside


61.5 log @ 310K 


Osmotic Pressure Equation


i = number of particles

M = Molarity of solution

R = Gas Constant 

T = Absolute T in Kelvin 


What are ion channels and the 3 main types

Ion channels help regulate the movement of ions in and out of the cell

UNGATED: Always open

VOLTAGE-GATED: open within a range of membrane potentials

LIGAND-GATED: Open in presence of a specific binding substance, like hormone or neurotransmitters 



What is an Enzyme-linked Receptor? 

An enzyme-linked receptor, also known as a catalytic receptor, is a transmembrane receptor, where the binding of an extracellular ligand causes enzymatic activity on the intracellular side. Hence a catalytic receptor is an integral membrane protein possessing both enzymatic catalytic and receptor functions.

Receptor tyrosine kinase, as in the fibroblast growth factor receptor. Most enzyme-linked receptors are of this type. Serine/threonine-specific protein kinase, as in bone morphogenetic protein.


What is a  G Protein-coupled receptor? 

DPCR have a membrane bound protein associated with a trimeric G protein. They initiate second messenger systems. 

  • Ligand binding engages g protein
  • GDP is replaced with GTP ; the alpha subunits detaches from the other two
  • The activated alpha subunits alters the activity of adenylate cyclase or phospholipase C
  • GTP is dephosphorylayed, and alpha subunit rebinds