1. Plasma Membrane Part 1 Flashcards
What are the functions of the plasma/cell membrane? What are the benefits of membrane-bound organelles in Eukaryotes?
- Acts as a boundary to control what enters and exits the cell
- Separates the internal and external environments
- Different parts of the cell can have varied conditions to allow specialisation
Describe phospholipid heads:
- Are hydrophilic (hydro=water) and polar
- Love water
Describe fatty acid tails:
- Are hydrophobic and non-polar
- Hate/fear water
Explain the Fluid Mosaic Model:
- Fluid= Because the phospholipids are moving
- Mosaic= Proteins sit in the phospholipids like tiles in a mosaic
What is the function of sterols, what are their different types and where are they located
- Change the fluidity of the membrane so that it is able to remain stable.
- Phytosterol in plants and animals and only Chlorestoral in animals
- Located in the hydrophobic region of the membrane
What are the 2 types of membrane proteins?
Can be integral (permanent parts of the membrane) or peripheral (temporary)
List the 6 functions of membrane proteins:
- Transport substances across the membrane
- Secure the cytoskeleton to the membrane
- Are enzymes
- Are receptors
- Responsible for cell-to-cell adhesion
- Act as identity marks
Describe the internal environment of multi-cellular organisms:
Contain interstitial/tissue (extracellular) fluid between cells (fluid bathes the cells, as well as blood plasma.
Describe the internal environment of unicellular organisms:
Contain only the internal environment of the cell itself.
What is a solute?
A substance dissolved in a liquid.
What is a solvent?
A liquid
What is a solution?
A solute and a solvent
What is a concentration gradient?
Describes the difference between relative amounts of solute and solvent in two solutions.
What does polar refer to? Give an example:
When one end of a molecule has a different charge to the other.
Eg. Water
What does non-polar refer to? Give an example:
When one end of a molecule has the same charge as the other.
Eg. Oil