HB PowerPoint 1 Flashcards
Why is it called Fluid Mosaic Model?
The reasoning behind the name ‘Fluid Mosaic Model’ is the following:
- Fluid: Molecules that make up the cells are constantly moving.
- Mosaic: Composed of many different molecules such as Phospholipids, Proteins, and Glycolipids.
- Model: ??
What is the main structure of Phospholipid molecules?
Phospholipid molecules are made up of a Phosphate group with lipids attached.
The phospholipid has 2 distinct regions:
- The head (hydrophilic).
- The tail (hydrophobic)
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In what particular way are these phospholipid molecules arranged in the cell membrane?
The phospholipid molecules are arranged in 2 layers, called a bilayer.
Where is Cholesterol located in the Phospholipids, and what is their role?
Cholesterol molecules are wedged in between the phospholipid molecules. These cholesterol molecules provide flexibility, and improve the structural integrity of the cell membrane.
What are the different types of proteins and their roles?
- Receptor Proteins: Allow the cell membrane to communicate with other cells.
- Channel Proteins: Transport of small, polar molecules e.g. water.
- Carrier proteins: Responsible for facilitated diffusion and active transport.
What is the 1st main function of the cell membrane?
Act as a physical barrier: Separate intracellular fluid (cytoplasm) from the extracellular fluids.
What is the 2nd main function of the cell membrane?
Regulate the passage of materials: Controls the movement of materials inside and outside of the cell.
What is the 3rd main function of the cell membrane?
Sense changes: The cell membrane contains receptors that can respond to change in extracellular fluid fast.
What is the 4th main function of the cell membrane?
Supports cell: Has structural molecules that give the cell shape, and allow it to join with other cells.
What are the only type of molecules that can pass through the cell membrane?
Only non-polar molecules are able to pass through the cell membrane. This is because the lipids are hydrophobic, meaning that they repel water. This means that polar substances are unable to enter the cell through the cell membrane.
