Transport Of Ions And Small Molecules Flashcards Preview

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Flashcards in Transport Of Ions And Small Molecules Deck (26):
1

Diffusion

Random molecular motion of solute down a chemical or electrochemical gradient

How move across membrane

2

Osmosis

Diffusion of water across a semipermeable membrane

3

Protein mediated transport

More rapid than simple diffusion

Substrate for molecule movement

Saturation kinetics and chemical specificity and stereospecificy because only certain molecules are transported

4

Saturation kinetics

Rate of transport increases until it reaches a point at which is stabilizes

There's a limit only so many proteins so can only move so many molecules

5

Facilitated vs. simple diffusion

Simple is linear

Facilitated if add proteins rate will increase

6

Allosteric binding sites

To control conformation of proteins and regulates transport

Glucose binding is competitive inhibition

7

Competitive inhibition

Is molecule binds site instead of glucose it blocks glucose binding to the protein and suppresses glucose transport

Lots of therapeutic agents, ex is antihistamines

8

Types of protein mediated transport

Facilitated transport

Active transport

9

Facilitated transport

Not linked to metabolic energy because moves down gradient and not blocked by substrate

Cannot move against electrical potential because requires energy

Cannot move uncharged particles against a gradient

Transported molecule may alter transport by producing conformational change in the transport protein

10

Active transport

ATP required, hydrolysis is needed to move against gradient, foundation of membrane potential

Metabolic inhibitors can block

Substances can move against concentration gradients

11

Membrane potential

Requires active transport

12

Types of transport proteins

Carrier proteins which bind molecules and move across membrane via conformational change

Channel proteins which have pores that open and close transmitting certain molecules across the membrane

13

Uniport

One type of molecule is transported across the membrane

14

Symport

Two different molecules transported in same direction

15

Antiport

Two different molecules transported in different directions

16

Types of channels

Open, closed, active transport, conformational transformation

ATP pump, ion channel which has greatest rate of transport and transporter

17

Carrier proteins

Can be active of facilitated transport

Uniporter, symporter, antiporter

18

Na, K ATPase

Most important ion transport via carrier proteins in the body

Maintains Low Na and high K in the cell by active transport and is responsible for membrane potential

3 Na out and 2 K in for each ATP hydrolyzed to ADP

2/3 of neurons energy needed here

Phosphorylation and dephosphorylation regulates

Chemical potential energy created and used to drive other systems ex: kidney

1 gate open at time creates specificity

19

Ca ATPase

Important in muscle

20

Na Ca Antiporter

Important in the heart

21

Na H antiport

PH of cytoplasm

22

Chloride bicarbonate antiporter

Important for pH

23

Na K Cl symporter

All at the same time

LasX binds to chloride symporter

24

Ion transport channels

Transmembrane alpha helicopter

b subunit forms a physical gate on outside of cell which opens to activate channel

Specificity not just dependent on molecule itself, ex: Na smaller than K but transports with water so cannot fit through K channel

25

Voltage gated channel

Ion transport channel

Activated by changes in membrane potential

Exist for Na, K and Ca

Different channels can be activated by depolarization or hyperpolarization

26

Ligand gated channel

Activated by ligand binding receptor which then opens the gate

Ketamine blocks this for Na and Cl which is activated by glutamate
Ketamine Blocks depolarization (making +) so no generation of action potential