UNIT 3 1A: Plasma Membrane Flashcards
Define Cell Theory
The theory that all living things are made up of at least one cell, and that these cells are the basic unit of life and came from pre-existing cells
Four common factors of Plant, Animal, Bacteria and amoeba cells
- Genetic Material
- Cytosol
- Ribosomes
- Plasma membrane
What is Cytosol
The liquid inside a cell, between the organelles (doesn’t include the organelles)
What is a Ribosome
A non-membrane-bound organelle involved in the synthesis of proteins
What is the Plasma Membrane
A membrane made up of two layers (known as a bilayer) of phospholipids that encloses the contents of a cell
Function of the Plasma membrane (rsc)
- Recognising other cells when forming tissue, or determining whether cells are foreign during an immune response
- Communication with other cells
- Selectively controlling which substances are transported into or out of the cell.
Define hydrophobic
Water-repelling; does not dissolve readily in water
Define Hydrophillic
Water-attracting or water-soluble; dissolves readily in water
Define semi-permeable membrane
A membrane that only lets certain substances cross it; also called partially permeable, differentially permeable or selectively permeable
What are the 4 components of the plasma membrane
- Phospholipids
- Proteins
- Carbohydrates
- Cholesterol
Parts of the phospholipids
- Hydrophillic glycerol and phosphate head
- Hydrophobic Fatty acid tail
Types of proteins in a cell membrane
- Integral/Transmembrane protein
- Peripheral protein
Functions of proteins in a cell membrane (TSC)
- Transport
- Signalling
- Cell-to-cell recognition
Role of carbohydrates in a cell membrane
- Adhesion between cells
- Cell recognition
Types of carbohydrate chains
- Glycoprotein (when attached to a protein)
- Glycolipid (when attached to a phospholipid head)
Role of cholesterol in the cell membrane
- Cholesterol helps to increase the stability of the plasma membrane without affecting the membrane’s fluidity (ability to flow)
- Increases membrane permeability
Define Fluid Mosaic Model
A model that represents the plasma membrane as a combination (mosaic) of phospholipids, proteins, cholesterol and carbohydrates that gives the membrane its fluid nature.
What defines a saturated lipid
When the fatty acids have only one bond between each carbon atom, which causes the lipids to pack together lightly
What defines an unsaturated lipid
Unsaturated fatty acids in the tails of a lipid have double bonds between some carbon atoms, which causes the lipids to pack together less tightly.
Benefits of unsaturated lipids in the plasma membrane
The presence of unsaturated lipids in the bilayer increases the fluidity of the plasma membrane
