Membranes Flashcards
Define hydrophobic
Water repels
Define hydrophilic
Water attracts
Define membrane
Outer substance of the cell
What is a polar head attracted to?
Attracted to other polar (charged) molecules
What is a non polar tail attracted to?
Repelling charged molecule, therefore prevent passage of ions through the membrane
What are lipids
Fats, oils, do not mix with water
More info on oil…
Base molecular membrane
Oil is thicker, slighter higher viscosity
Reason why there is life
They separate themselves as much as possie
Define phospholipids
Phosphates that are fats and it’s another name for cell membrane
Break down the meaning of phospholipid bilayer
Phospho- phosphates
Lipids- fats
Bi- 2
Layer- layers
What is a polar head
Phosphate head
What is a non-polar tail?
Fatty (oil) acid
Explain how hydrophobic and hydrophilic properties of phospholipids help maintain the structure of the cell
When surrounded by water, the molecular properties phospholipids will cause them to form structures in which the lipid tails are not in contact with water
What’s a metaphor for a phospholipids?
Magnets, north likes south and polar likes non polar
Are phospholipids glued together?
No, they are very flexible. They act very similar to magnets
What happens when the tails meet?
When the tails meet, the fatty acids will meet up to feel balanced and stable
What does it mean to be selectively permeable?
It means that selectively means “controlled” and permeable means “entry/exit of molecules”
What is selectively permeable also called?
Semi-permeable
Some molecules pass through easily because of…..
Diffusion
Some molecules go through a protein tunnel because of…
Facilitated diffusion (too polar or too big)
Other molecules need energy to get trough the membrane because of…
Active transport
Large molecules use their own membrane to get through a phospholipids because of…
Endo/exo-cytosis
What are the 6 functions of the plasma membrane
1) hold the cell together
2) control what goes in and out
3) protect the cell
4) allow the cell to recognize and be recognized
5) bind to other cells and molecules
6) a site for biochemical reactions
List 7 functions of membrane proteins.
1) hormone binding
2) fixed enzymes
3) cell adhesion
4) channels for facilitated diffusion
5) cell receptors for communication
6) active transport pumps
7) electron carriers in photosynthesis and cell respiration
What is the fluid mosaic model?
The fluid mosaic model tells us that the structure of the membrane is flexible, adaptable and in motion. It is not solid, or fragile like skin of a balloon
Break down “fluid mosaic model”
Fluid- always moving, not solid
Mosaic- collection of things stuck together
Model- representation of real life