Learning objective 3 cell membrane Flashcards
What is the sodium-potassium pump
It is a protein and enzyme in the cell membrane that uses ATP to push sodium and potassium against their concentration gradient in the body
What is a simple diffusion
Simple diffusion is when things move from high concentration to low concentration across the cell membrane (phospholipid bilayer). It only lets in things that are small ad non-polar.
What are the different types of passive transport across the cell membrane?
Simple diffusion, facilitated diffusion, osmosis
What are the active transport mechanisms in the cell membrane
Primary active transport and vesicular transport,
What is diffusion
Diffusion is the movement of things from high concentration gradient to low concentration
What is facilitated diffusion and what are the different types
Facilitated is a passive transport mechanism that uses proteins to perform diffusion it doesn’t require ATP because it uses kinetic energy. The two types are channel-mediated and carrier-mediated. They allow for bigger polar solutes to enter the cell
What is osmosis
Osmosis is the diffusion of water molecules through protein channels specific to water or on some occasions through the cell membrane
What is the protein channel for osmosis called
An aquaporin
What is the concentration gradient for Na, K, Ca in the cell
Sodium and calcium want to come into the cell, while potassium want to leave the cell
What is the difference between filtration and diffusion
Filtration uses pressure to move things from high concentration gradient to low concentration gradient while diffusion is movement from high to low using kinetic energy.
How does the sodium-potassium pump work?
The pump has binding sites for three Sodium ions that hitch a ride onto it the protein pump also acts as an enzyme for ATP once the ATP comes in the sodium coming onto the pump causes a reaction for the hydrolysis of the ATP which causes a huge energy surge that allows the pump to change shape and release the sodium to the ECF 2 potassium ions then come into the binding sites which trigger the release of the phosphate causing the protein to revert back to its original shape causing the potassium to be released into the ICF
What is vesicular transport?
This is when things are transported through the cell membrane in membranous sacs called vesicles. It is an active form of transport across the cell membrane.
What are the three major types of Vesicular transport
Phagocytosis, pinocytosis, receptor-mediated endocytosis
What is phagocytosis and give an example
Phagocytosis (cell eating) is when the cell engulfs larger substances into a vesicle. An example is white blood cells engulfing bacteria
What is pinocytosis and give an example
Pinocytosis (cell drinking) is when the cell takes in liquid from the ECF. An example would be In the intestines where they are constantly absorbing nutrients
