Chapter 4: Transport Flashcards
Passive transport
Does not require energy
High to low concentration
Active transport
Requires energy
Low to high concentration
Simple Diffusion
Things move from high to low concentration without added energy
The farther away something is, _____
The slower it will move
Higher concentration difference means _______
Faster flow
What do membranes do concerning concentration in a cell?
Controls diffusion
What four substances can easily go through a lipid bilaryer?
-diatomic oxygen
-CO2
-fatty acids
-steroid hormones
What struggles getting through a lipid bilayer?
Hydrophilic substances; enter the cell using ion channels
Membrane Potential
Opposite charges on either side of the membrane create a potential
What can establish a membrane potential?
Ion channels
What are the 3 ways ion channels can be controlled?
-ligand gated
-voltage gated
-mechanically gated
Mediated Transport
Facilitated and active transport
Transporters
Conformationally change integral membrane proteins
How to transporters connect to their ligands?
High specificity, resulting in high saturation
What is the rate of active transport determined by?
-concentration of substance
-saturation value of protein
Active transport
-requires a protein
-requires energy
Primary Active Transport
Uses ATP to move things against their concentration gradient
Secondary Active Transport
Uses the concentration gradient established by the primary active transport to move another substance
Cotransport / Simport
Secondary Active Transport moving something in the SAME direction as Primary
Power transport / Antiport
Secondary Active Transport moving something in the OPPOSITE direction as Primary
What does a “pump” refer to?
Something that has to work to move something where it shouldn’t be
What is the result of a sodium potassium pump?
3 (+) sodium moved out of the cell
2 (+) potassium move inside the cell
What is the concentration difference of SODIUM in a cell?
Outside: 145
Inside: 10
What is the concentration difference of POTASSIUM in a cell?
Outside: 5-6
Inside: 150
What is the most important pump in the body?
Sodium-Potassium Pump
How much of all the body’s energy goes to the sodium-potassium pump?
1/3 of the body’s energy
Osmosis
The movement of water across a membrane
Aquaporins
Proteins that allow water to move from high to low concentration
