Transport mechanisms Flashcards
What is the function of a cell membrane?
What is a cell membrane made of?
It controls what goes in and out of the cell. This is because it is selectively permeable.
Made of a phospholipid bilayer.
What is a phospholipid bilayer?
2 layers of back to back phospholipids
What are phospholipids made up of?
They are made up of a Glycerol molecule, a phosphate group and 2 fatty acid strings
The head of the phospholipid is what?
What charge does the head have?
It is also hydrophilic which means it is attracted to water.
A positive charge
The tails of a phospholipid is what?
They are hydrophobic which means they are scared of water. They have a negative charge.
What three things is a cell membrane made of?
An intrinsic protein, extrinsic protein and cholesterol
What is an intrinsic protein?
They span the whole length of the membrane. They allow things to pass though from one side of the membrane to the other.
What do extrinsic proteins have and what do they do?
When an extrinsic protein is associated with a carbohydrate protein what is it called?
They have carbohydrate branches which are used as receptors for cell signaling. They serve in the transport of molecules.
They are known as glycoproteins.
What do cholesterols add to the cell membrane?
They add structural stability
Why is an intrinsic protein needed in facilitated diffusion?
What concentration does it go from in this process?
The intrinsic protein are needed to carry large or charged molecules across the membrane
From a high concentration to a low concentration
What happens in active transport?
Molecules move from where there is a low to a high concentration (against the concentration gradient). To do this energy if required in the form of ATP. The ATP joins onto the carrier protein and becomes ADP. This produces enough energy to push the molecule through to the other side of the membrane
