(B4) Cell Transport Mechanisms Flashcards
Purpose of the cell surface membrane
To maintain the osmotic balance of the internal environmentand control what goes in and out of the cell
Types of Passive Movement
- Diffusion
- Osmosis
- Facilitated Diffusion
Types of Active Movement
Active Transport
Properties of cell membranes
- Partially Permeable
- Flexible
- Fluid
Chemical structure of the cell membrane
- Lipids (phospholipids and cholesterols)
- Proteins
- Carbohydrates (Glycoproteins and glycolipids)
Regions of the phospholipids
- Polar head
- Two non-polar tails
What does polar mean
Hydrophilic, is soluble in water
What does non-polar mean?
Hydrophobic, is non-soluble in water
What are the tails of the phospholipids?
Fatty acid chains
What is the head of the phospholipids?
Phosphate groups
In the fluid mosaic model cell membranes are “fluid” because…
The phospholipids and proteins move around via diffusion
How do the phospholipids move?
Mainly sideways within their own layer
What is facilitated diffusion?
Where certain substances that cannot diffuse through the phospholipid bilayer use proteins to diffuse pass the bilayer
What substances cannot diffuse pass the phospholipid bilayer?
- Large polar molecules such as glucose or amino acids
- Ions such as sodium ions (Na+) or Chloride Ions (Cl-)
What are the types of proteins needed for facilitated diffusion?
- Channel Proteins
- Carrier Proteins
Each individual protein only allows for one type of molecule or ion to pass through
