Lecture 10: Cell transport (Part 2) Flashcards
What is active transport?
process in cells of transporting molecules or ions across the membrane against their concentration gradient to concentrate them to one side
Is active transport a spontaneous process?
no
What are pumps?
membrane transport proteins that carry out active transport
Does active transport require energy?
Yes
What form of energy does active transport require?
ATP
How do you call a transport protein that pumps ions specifically across a membrane?
electrogenic pump
What type of gradient do electrogenic pumps create?
electrochemical gradient
How do electrogenic pumps work?
they convert chemical energy from ATP to electrical energy which can be used for cellular work.
What is the main electrogenic pump for animal cells?
the sodium/potassium (Na+/K+) pump
What is the main electrogenic pump for plant, fungi and bacteria cells?
proton (H+) pumps
What are the two combined forces that drive the diffusion of ions across a membrane?
- chemical force
2.electrical force
What does chemical force result from? (that drives diffusion of ions across a membrane)
from the ion’s concentration gradient
What does electrical force result from? (that drives diffusion of ions across a membrane)
from the membrane potential
What is the membrane potential?
voltage in cells created by unequal distribution of ions generated by pumps
What are electrochemical gradients used for?
- Neuron cell stimulation and propagation of impulse
- Muscle cell stimulation
- Powering of bacteria’s flagella to swim
- Secondary active transport: organisms transport substances against their concentration gradients using electrochemical gradients
Where does the potential energy for electrochemical gradient come from?
During primary active transport, the chemical energy in ATP is transformed into the potential energy of an electrochemical gradient.
What is secondary active transport?
Using the energy stored from primary active transport to drive the active transport of another chemical
the ATP indirectly drives the transport of a chemical
What is another name for secondary active transport?
cotransport
What is an example of how plants use secondary active transport?
Plants and other organisms commonly use the gradient of hydrogen ions generated by proton pumps to drive the active transport of substances into the cell.
What is an example of how animals use secondary active transport?
Animal use the gradient of sodium ions generated by Na+/K+ pumps to drive active transport of substances in digestive and urinary systems.
What are the three different types of carriers/transporters?
- uniporter
- symporter
- antiporter
What type of carrier/transporter is this?