Page 68 - Demo 1

molecules such as ions, and large molecules like sugars and amino acids. The
passage of these molecules relies on specific transport proteins embedded in
the membrane.
Cell membranes oen include receptor sites for interacon with specific
biological chemicals such as certain hormones, neurotransmiers and immune
proteins. In this way, the cell can recognize and process some signals received
from the extracellular environment.

In many cases the cell membrane also helps to hold the cytoskeleton
(which is within the cell) in place. This is achieved by some proteins in the cell
membrane aaching to some cytoskeletal fibers and helps to define and
maintain the shape of the cell.

Along with membrane proteins, the carbohydrates found in cell
membranes form disncve cellular markers that allow cells to recognize each
other. These markers are very important in the immune system, allowing
immune cells to differenate between body cells, which they should not aack,
and foreign cells or ssues, which they should.

Learning Tasks and A ssesment

Acvity 1. Fill in the table with the required informaon that pertains to the
structure and funcon of the cell membrane.

Component Location Function

Phospholipids

Cholesterol

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