Phospholipid Bi-layers Flashcards
What is a polar molecule ?
A molecule that has a partial charge. Polar molecules can stick together.
What is a non-polar molecule ?
A molecule with no charge.
What gives water it’s properties.
The hydrogen bonds allow water to be a liquid at room temperature with a boiling point of 100degrees. It is a polar molecule.
Give the functions of a plasma membrane.
Surrounding barrier between Cytoplasm and the environment. Controls movement of substances in and out of the cell.
Give the functions of internal membranes.
Separate out organelles from Cytoplasm, contain some isolate enzymes such as lysosomes, act as an internal transport system and are a surface for reactions to occur.
When and how was the mosaic structure discovered.
In 1950 the electron microscope found proteins in a mosaic structure in membranes.
What is a condensation reaction ?
The formation of a bond in which water is expelled.
What bonds the phospholipid head and glycerol ?
A condensation reaction bond.
Ester bond
What bonds the glycerol and fatty acid tail ?
A condensation reaction bond.
Ester bond
Name the 3 parts of a phospholipid and facts about them.
Phospholipid head - Hydrophilic - loves water and is water soluble.
Glycerol
Fatty acid tail- Hydrophobic- hates water - water insoluble.
Draw and explain what happens when a phospholipid is placed on the surface of water.
Hydrophilic heads face water.
Hydrophobic tails face away.
What is it called when phospholipids are fully submerged underwater. Draw and explain.
Miscell
Phospholipid create droplets with the hydrophobic tails all facing onwards to protect each other and the hydrophilic heads facing outwards towards the water.
How are two separate bodies of water separated and give an example of this in a cell.
Phospholipid bi-layer is creates between the extra-cellular fluid and cytosol.
Two phospholipids join with their hydrophobic tails facing in towards each other and hydrophilic heads facing outwards towards each body of water.
Explain what types of substances phospholipid bi-layers allow through.
Lipid soluble, small, non polar molecules such as carbon dioxide and oxygen molecules for through.
Larger, water soluble, polar substances are prevented from entering and leaving the cell.
What is and what are the functions of the glycoproteins in a phospholipid cell membrane.
Branching carbohydrate portions of a protein which act as a recognition site for chemical hormones.
They help cells attach to each other to form tissues and allow cells to recognise each other.
Can be cell surface receptors for hormones.
Give an example of a phospholipid and what it recognises.
Lymphocytes recognise the organisms own cells.
What is and what are the functions of glycolipids in a phospholipid cell membrane ?
Acts a recognition site for cholera toxins, maintains cell stability and attach to each other to form tissues.
Made of carbohydrates covalently bonded with lipids. They extend outside the cell.
What is and what are the functions of phospholipids in the phospholipid cell membrane.
Makes the cell membranes flexible and self-healing.
What is and what are the functions of carrier proteins in the phospholipid bi-layer.
Spans width of bi-layer.
Binds to ions or molecules( like glucose or amino acids) then change shape or order to move these molecules across the membrane.
Allows active transport across the membrane.
Provides structural supposed, allows cells to adhere together, acts as hormone receptors.
What is and what are the functions of the Chanel proteins in the phospholipid bi-layer.
Created a shoot for which water can travel through which water soluble ions diffuse across.
Hydrophilic water pores allow water soluble molecules through.
Provides structural support , allows cells to adhere together, act as hormone receptors.
Name the parts of the phospholipid cell membrane.
Glycoproteins Glycolipid Peripheral protein molecules Carbohydrate chains Partly embedded protein molecules Protein channel Carrier proteins Phospholipids
Why is it known as a fluid mosaic model ?
Fluid - individual phospholipid molecules can move freely within membrane giving it fluidity consequently it can change shape.
Mosaic - made up of a combination of different proteins and phospholipids.
Give functions of membrane bound / intrinsic/ integral proteins.
Allow cells to adhere together.
Hormone receptors - cell surface.
Can be enzymes.
What are the alternative names for carrier and channel proteins ?
Intrinsic or integral proteins.
What are the functions of peripheral protein molecules.
They lie on the surface giving cell strength and acting as hormone receptors.
What types of molecules does the phospholipid bi-later allow through ??
Small, lipid soluble, non-polar molecules such as water and gases.
What types of molecules are not allowed through by the phospholipid bi-layer ?
Large , polar molecules which are lipid and water insoluble. Such as ions and amino acids.
Which component of a fluid mosaic model is a hydrocarbon ?
The fatty acid tails and cholesterol.
Describe functions of the bi-later.
Allows only small, water and lipid soluble, non-polar molecules through.
Allows cells to maintain a different concentration on either side.
Makes membranes self-sealing and able to fuse with other membranes to form vesicles.
Give flexibility and fluidity.
Give a function of a glycoprotein.
Cell recognition.
Which part of the Mosaic model acts as recognition sites for substances such as insulin and act as antigens.
Glycoproteins.
Which part of the fluid mosaic model waterproofs membrane and makes it more rigid ?
Cholesterol
Which part of the fluid mosaic model makes the membrane fluid and allows fat soluble molecules but not water soluble substances to cross.
Phospholipids.
What substances do phospholipids let across ??
Fat soluble but not water soluble molecules.
What part of the fluid mosaic model acts as enzymes ?
Extrinsic proteins.
What part of the fluid Mosaic model gives stability and helps adhesion to each other ??
Glycolipids.
What kind of movement does the fluid mosaic model have ?
Lateral
What is another term for cell surface membrane ?
Plasma membrane
What bonds join the phospholipid and tail to the glycerol ?
Condensation reactions in which water is expelled and an Ester bond is created.
What happens when phospholipids are placed on the surface of water.
Draw diagram
Hydrophilic heads face water.
Hydrophobic tails pull away from water.
How do phospholipids act when submerged in water.
Draw diagram.
This is called Miscell.
Phospholipids create droplets as the fatty acid tails face onwards towards each other and the heads face out.
Describe how a phospholipid molecule differs in structure from a triglyceride molecule.
Phosphate has a phosphate
Phospholipid only had two fatty acids
Create a chemical test to show that coconut contains lipids.
(This could be used as a test for any substance).
Place or crush the substance in ethanol alcohol. If the substance has any lipids they will be dissolved meaning the phospholipid bilayer is ruptured. This will cause a (white) emulsion to leak out.
How does a phospholipid molecule differ from a triglyceride molecule.
It has a phosphate head.
