cell membrane function

 

Question: 16 of 47

INCORRECT

• Time Remaining: 07:55:54

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What is the Cell Membrane?

• The cell membrane (also called the plasma membrane) is the thin, flexible outer covering of a cell.

• It acts like a skin for the cell, but it is not just a barrier — it is also selective, meaning it controls what goes in and out.

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Main Functions of the Cell Membrane

1. Protection

   • It separates the inside of the cell from the outside environment.

   • Keeps harmful substances out.

2. Control (Selective Permeability)

   • It allows some substances (like nutrients, water, oxygen) to enter.

   • It allows waste (like carbon dioxide) to leave.

   • Blocks things that the cell does not need.

3. Communication

   • The membrane has proteins and receptors that help the cell receive signals (like hormones or nerve signals).

   • This helps cells "talk" to each other.

4. Support and Shape

   • It gives the cell structure and maintains its shape.

   • Works with the cytoskeleton inside the cell to keep stability.

5. Transport

   • The membrane uses different methods to move materials:

     • Passive transport (no energy, e.g., diffusion, osmosis).

     • Active transport (requires energy, moving things against concentration).

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✅ In short:
The cell membrane protects the cell, controls what enters and leaves, helps communication, and keeps the cell’s shape.

Which of the following is the correct structure and function of the cell membrane?

A double glycoprotein structure with embedded lipid bodies provides shape and rigidity to the cytoplasm.

The double structure is not composed of glycoprotein.

A double layer of phosphate proteins with lipid channels allows molecules to pass from the inside to the outside of cells.

The double layer is not composed of phosphate proteins.

Nonpolar phosphate heads and polar lipid tails form a bilayer to control the transport of proteins.

MY ANSWER

The heads are polar and the tails are nonpolar; molecules pass through protein channels.

A phospholipid bilayer with embedded proteins regulates molecules entering and leaving cytoplasm.

The cell membrane consists of a phospholipid bilayer with polar phosphate heads, nonpolar lipid tails, and embedded proteins, which permit the movement of molecules across the membrane.