L.7 II Membrane Receptors

Question 1

What are the 3 types of passive Transport

Answer 1

1. Simple diffusion
2. Facilitated diffusion
3. Osmosis

Question 2

Explain Simple diffusion

Answer 2

No transported Required

small non-polar, lipid-soluble

high to low concentrations

(h2o)

Question 3

Explain Facilitated diffusion

Answer 3

Uses transporters to move impermeable solutes across the cell membrane

Question 4

Explain Osmosis

Answer 4

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

Question 5

Explain active transport and it’s two forms

Answer 5

Requires energy from ATP or an existing favorable gradient.

1. Primary
2. Secondary ( antiport and symport)

Question 6

Differentiate Endocytosis

exocytosis, pinocytosis, and phagocytosis

Answer 6

Endocytosis engulfing material into cell

Exocytosis Releasing material out of cell

Pinocytosis: solutes and liquid into vessicles endo

Phago: bacteria ingestion, larger molecules, solid.

Question 7

How is the membrane potential maintained?

Answer 7

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.

Question 8

Nerst Equation

Answer 8

E = Electrical potential created by one ion

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

61.5 log @ 310K

Question 9

Osmotic Pressure Equation

Answer 9

II = iMRT

i = number of particles

M = Molarity of solution

R = Gas Constant

T = Absolute T in Kelvin

Question 10

What are ion channels and the 3 main types

Answer 10

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

Question 11

What is an Enzyme-linked Receptor?

Answer 11

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.

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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.

Question 12

What is a G Protein-coupled receptor?

Answer 12

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