Select the odd one out.
(a) The movement of water across a semi-permeable membrane is affected by the amount of substances dissolved in it
(b) Membranes are made of organic molecules like proteins and lipids
(c) Molecules soluble in organic solvents can easily pass through the membrane
(d) Plasma membranes contain chitin sugar in plants.

AcademicBiologyNCERTClass 9

Correct Answer: (d) Plasma membranes contain chitin sugar in plants


Explanation:
 The movement of water across a semi-permeable membrane is affected by the number of substances dissolved in it. 

Membranes are made of organic molecules like proteins and lipids

Molecules soluble in organic solvents can easily pass through the membrane


The fluid mosaic model is used to describe the structure of the plasma membrane. This model was proposed by Nicolson and Singer in 1972. This model suggests that the plasma membrane is composed of lipids and proteins primarily.


However, small amounts of carbohydrates can also be found in the plasma membrane. The proteins of the plasma membrane can be integral or peripheral membrane proteins. These proteins move through the lipid bilayer, which gives the plasma membrane a typical fluidic nature.

The fluid mosaic model of the plasma membrane can be represented as follows:



Figure: Fluid mosaic model of the plasma membrane.
raja
Updated on 10-Oct-2022 13:28:47

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