Select the correct statement from the following regarding cell membrane.

Select the correct statement from the following regarding cell membrane.
  1. $\mathrm{Na}^{+}$and $\mathrm{K}^{+}$ions move across cell membrane by passive transport
  2. Proteins make up 60 to $70 \%$ of the cell membrane
  3. Lipids are arranged in a bilayer with polar heads towards the inner part
  4. Fluid mosaic model of cell membrane was proposed by Singer and Nicolson

Solution

In 1972 , Singer and Nicolson proposed fluid mosaic model for internal structure of plasma membrane. This is most widely accepted model for plasma membrane. According to this model, a membrane consists of a continuous bilayer of phospholipid molecules in which globular proteins are embedded. The lipids are arranged in a bilayer with polar heads towards outerside.

Asked in: NEET 2012 (Screening)

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