B6 Cell membrane Flashcards
Which one is hydrophilic and which one is hydrophobic between phosphate head and tail ( fatty acid chain) ?
Phosphate head is hydrophilic (polar) and tail is hydrophobic (non-polar)
What is the cell membrane?
A barrier between cell and environment which is partially permeable
What are the three transport methods to pass through the cell membrane?
- Active transport
- Diffusion
- Osmosis
Why is the cell membrane called fluid mosaic?
It is called ‘fluid’ because the molecules within the membrane are able to move around
It is called ‘mosaic’ because it is made from a variety of different molecules arranged into a mosaic
What is the definition of osmosis?
The net movement of water particles from a high water potential to a low water potential across a partially permeable membrane
What number means there is a high water potential?
0
What number means a low water potential?
negative
What water potential does pure water have?
high (0)
What does isotonic mean?
When water potential is the same inside and outside the cell
-Solutions of equal solute concentration
What does hypertonic mean?
It is the solution with the higher solute concentration
Why does hypotonic mean?
The solution with the lower solute concentration
What are the words for outside and inside of the cell?
- Extracellular and Intracellular
What is the layer that makes up the cell membrane called?
Phospholipid bilayer
What happens in between phospholipid bilayer?
Simple diffusion which is passive and is from high to low concentration
What specific characteristics are needed for particles to pass through the phospholipid bilayer?
The molecules need to be small, soluble and uncharged
What is the function of channel proteins?
To transport small, charged (ions) and soluble molecules quickly through the membrane.
What is the transport method in the channel protein?
Facilitated diffusion which occurs from high to low concentration and it is passive and requires help from proteins
What is the function of carrier proteins?
Molecules bind to them and which changes the tertiary structure of carrier proteins
What sort of molecules can pass through carrier proteins?
Large molecules eg. glucose or amino acids
What transport methods occur in carrier proteins?
Facilitated diffusion and active transport
What does the cholesterol in the phosphate bilayer do?
Adds rigity to the bilayer
What do receptors do in the cell membrane?
Allows signaling molecules to attach to them to trigger a response , they have complimentary shapes
What is the role of enzymes in the cell membrane?
They hydrolyse bonds between molecules so that they can pass through the membrane eg. dipeptides into amino acids
