What are the two main points of the fluid mosaic model? What affects fluidity of the plasma membrane? Why is fluidity important? Describe the 6 functions of membrane proteins. Which two aspects of a membrane confer selective permeability? Compare channel and carrier proteins. Can channel proteins participate in active transport? Solution Fluid mosaic model was proposed by Singer and Nicolson to explain the selective permeability of the plasma membrane. According to it, plasma membrane is a mosaic of phospholipids, cholesterol and proteins. The proteins are embedded in the phospholipid bilayer. THe phospholipids have hydrophobic tail end and hydrophilic head. The mosaic nature of the plasma membrane helps it to be fluid. The fluidity is interrupted by occasional membrane proteins. The ratio of saturated to unsaturated fatty acids also contribute to the fluidity of the membrane. Unsaturated fatty acids \"kinks\" help the membrane to be fluid at low temperatures. Cholesterol also helps to keep the membrane in a uniform state of fluidity. Functions of membrane proteins include The size of the pores and hydrophilic/hydrophobicity prevents or allows the permeability of most of the molecules. the other important aspect which confer selective permeability to the cell is the membrane proteins Channel proteins are lipoproteins, while carrier proteins are glycoproteins. Carrier proteins can transport molecules or ions against the concentration gradient, while channel protein cannot. Carrier proteins move across the membrane, whereas channel proteins do not move while transporting molecules or ions. Carrier proteins can mediate both active and passive transport, while channel proteins can mediate only passive transport.

1. What are the two main points of the fluid mosaic model?
What affects fluidity of the plasma membrane? Why is fluidity important?
Describe the 6 functions of membrane proteins.
Which two aspects of a membrane confer selective permeability?
Compare channel and carrier proteins. Can channel proteins participate in active transport?
Solution
Fluid mosaic model was proposed by Singer and Nicolson to explain the selective permeability
of the plasma membrane. According to it, plasma membrane is a mosaic of phospholipids,
cholesterol and proteins. The proteins are embedded in the phospholipid bilayer. THe
phospholipids have hydrophobic tail end and hydrophilic head.
The mosaic nature of the plasma membrane helps it to be fluid. The fluidity is interrupted by
occasional membrane proteins. The ratio of saturated to unsaturated fatty acids also contribute to
the fluidity of the membrane. Unsaturated fatty acids "kinks" help the membrane to be fluid at
low temperatures. Cholesterol also helps to keep the membrane in a uniform state of fluidity.
Functions of membrane proteins include
The size of the pores and hydrophilic/hydrophobicity prevents or allows the permeability of most
of the molecules. the other important aspect which confer selective permeability to the cell is the
membrane proteins
Channel proteins are lipoproteins, while carrier proteins are glycoproteins.
Carrier proteins can transport molecules or ions against the concentration gradient, while channel
protein cannot.
Carrier proteins move across the membrane, whereas channel proteins do not move while
transporting molecules or ions.
Carrier proteins can mediate both active and passive transport, while channel proteins can
mediate only passive transport