Question

Select all of the statements that are true.

1. Membranes can contain lipids, proteins, and carbohydrates.

2. Fatty acids will form a membrane bilayer in an aqueous solution.

3. Membranes are static.

4. Membrane composition is symmetrical.

Answer 1

Answer-

According to the given question-

We know that cell membrane is made up of lipid bilayer. Lipid or Fatty acids content is about 50% and rest are proteins in a cell membrane of animal cell. Lipid present in cell membrane are amphipathic in nature i.e. having both hydrophobic and hydrophobic portion .

Generally phospholipid are found in cell membrane which have a hydrophilic head and two hydrocarbon tails which are hydrophobic in nature. Hydrocarbon tails are made up of fatty acid having length between 14 to 24 carbon.

Phospholipid form a bilayer when aquous environment is provided because the hydrophilic molecule can easily dissolve in water due of presence of polar group or charged group which can form either hydrogen bond with water or electrostatic interactions.

Hydrophobic molecule are insoluble in water And they do not have charged or polar group due to which they can not form the hydrogen bond with water so they are present interior to the lipid bilayer.

So when fatty acid are placed in a aqueous solution it can not form lipid bilayer because it only have hydrophobic hydrocarbon tail.

Cell membrane is dynamic not static because several components of the cell membrane are changed according to the environment, so membrane are continuously remain in flux.

Cell membrane is asymmetrical because they have different lipid composition in each bilayer.

Cell membrane contains lipid. Protein as well as carbohydrates. Some protein are present at the surface while some are integral part of membrane. Carbohydrates attached to the protein form glycoprotein.

So correct answer is (a) cell membrane have carbohydrates, protein and lipid.