Biology: Cell Membranes Flashcards
What is the Plasma Membrane Structure?
Phospholipid Bilayer:
- Intrinsic Protein: Channel Protein, Carrier Protein
- Extrinsic Protein: Glycoprotein
- Glycolipid
- Phospholipid: Hydrophilic head - Polar, Hydrophobic tail - Nonpolar - No charge
- Cholesterol
What is a Channel Protein?
Channel Protein carries out facilitated diffusion (allowed by the protein) number of channel Protein increase rate of diffusion.
What is Carrier Protein?
2 Types:
- Active transport require ATP to change orientation
- Only do facilitated diffusion and don’t require ATP to change orientation
What is a Phospholipid?
Tails can be saturated or unsaturated fats –> More saturated (bend in fatty acid chain) phospholipid –> more permeable –> more permeable
What is the function of membranes?
To separate parts of the cells to keep the contents separate e.g. lysosomes. Controls passages of substance across it.
What is a Phospholipids Bilayer?
The two parts of the membrane that provides a barrier to polar substances (water soluble substances)
What is a Cholesterol?
Substance that binds to the tails of Phospholipids and therefore reduces fluidity of the membrane.
What is an Intrinsic Protein?
Proteins that pass all the way through the membrane
What is ATP Synthase?
An example of an enzyme that is an intrinsic protein in the cristae membrane of Mitochondria
What is a Carrier Protein?
Has a receptor site that substances with a complementary shape can bind to so they are transported across the membrane.
What is a Channel Protein?
Has a space through which a substance with a complementary shape can travel through to cross the membrane
What is an Entrinsic Protein?
A protein that is found on the surface of the membrane or which passes part the way through the membrane.
What is a Receptor?
An extrinsic protein with a specific shape (tertiary structure) that other substances such as a hormone or neurotransmitter bind to.
What is an Antigen?
A type of protein is used in cell recognition
How is the phospholipid membrane structured?
The phospholipids can move positions within the layer. Th heads (glycerol and phosphate) of the phospholipids are polar and therefore hydrophilic and the tails (two fatty acid chains) are non-polar and therefore hydrophobic. This means that a bi-layer of phospholipids form with the tails orientated towards the centre of the bi-layer. This forms a barrier that restructures the movement of polar or large substances across the membrane.
