Name:
Cell transport
mechanisms
BTEC Applied Science
Unit 5: Principles and Applications 2 - Biology
Revision Notebook
, Cell membrane structure
Fluid mosaic model:
The fluid mosaic model was proposed by Singer and Nicolson in 1972. It is a proposal about the structure of the plasma membrane of animal cells. The
main component is the phospholipid bilayer made up of phospholipids. The bilayer acts as a barrier allowing some substances through the membrane but
not others. Within the membrane are proteins which can be intrinsic or extrinsic. Other substances like cholesterol and glycoproteins are also present. The
bilayer acts as a two-dimensional liquid so the molecules can move laterally in relation to each other but not the other way.
Intrinsic protein: Receptors: Phospholipid: Antigens:
Proteins that extend from Found on the surface of Hydrophilic heads are These are proteins on the
one side of the membrane cells, they are often made adjacent to water (extra surface of the membrane
to the other. Often make of glycoprotein cellular fluid and that are recognised by
up protein channels or (carbohydrate and protein cytoplasm), hydrophobic white blood cells and
carrier proteins. combined). They detect tails face each other to antibodies. They will
specific molecules such as avoid water. either be recognised as
hormones and “self” or as belonging to
neurotransmitters. another organism, in
which case they will
trigger an immune
response.
EXTRA CELLULAR FLUID
CYTOPLASM
Extrinsic protein: Carrier proteins: Cholesterol: Protein channels:
Only found in one layer of Proteins within the Holds phospholipids Proteins that extend
the phospholipid bilayer. molecule which are able to together making them less through the membrane
Also known as peripheral actively carry larger fluid. This reduces the and have a pore through
proteins because they do molecules through the permeability of the them. Some are able to
not go all the way through. membrane. phospholipid bilayer. open or close as needed.
Act as transport molecules
and also receptors.
Cell transport
mechanisms
BTEC Applied Science
Unit 5: Principles and Applications 2 - Biology
Revision Notebook
, Cell membrane structure
Fluid mosaic model:
The fluid mosaic model was proposed by Singer and Nicolson in 1972. It is a proposal about the structure of the plasma membrane of animal cells. The
main component is the phospholipid bilayer made up of phospholipids. The bilayer acts as a barrier allowing some substances through the membrane but
not others. Within the membrane are proteins which can be intrinsic or extrinsic. Other substances like cholesterol and glycoproteins are also present. The
bilayer acts as a two-dimensional liquid so the molecules can move laterally in relation to each other but not the other way.
Intrinsic protein: Receptors: Phospholipid: Antigens:
Proteins that extend from Found on the surface of Hydrophilic heads are These are proteins on the
one side of the membrane cells, they are often made adjacent to water (extra surface of the membrane
to the other. Often make of glycoprotein cellular fluid and that are recognised by
up protein channels or (carbohydrate and protein cytoplasm), hydrophobic white blood cells and
carrier proteins. combined). They detect tails face each other to antibodies. They will
specific molecules such as avoid water. either be recognised as
hormones and “self” or as belonging to
neurotransmitters. another organism, in
which case they will
trigger an immune
response.
EXTRA CELLULAR FLUID
CYTOPLASM
Extrinsic protein: Carrier proteins: Cholesterol: Protein channels:
Only found in one layer of Proteins within the Holds phospholipids Proteins that extend
the phospholipid bilayer. molecule which are able to together making them less through the membrane
Also known as peripheral actively carry larger fluid. This reduces the and have a pore through
proteins because they do molecules through the permeability of the them. Some are able to
not go all the way through. membrane. phospholipid bilayer. open or close as needed.
Act as transport molecules
and also receptors.
