Lipids - intro, triglycerides, phospholipids

Question 1

What is the difference between fats and oils?

Answer 1

Fats are solid at room temp. Oils are liquid at room temp.

Question 2

What are lipids?

Answer 2

Non-polar molecules Insoluble in water. Large complex molecules known as macromolecules, which are not built from repeating units, or monomers.

Question 3

What are triglycerides?

Answer 3

A triglyceride is made by combining one glycerol molecule with three fatty acids. Glycerol is an alcohol and the fatty acids are carboxylic acids.

Question 4

How does the glycerol react with the fatty acids?

Answer 4

The hydroxyl groups of both molecules interact, leading to the formation of three water molecules and bonds between the fatty acids and glycerol molecule.

Question 5

What is the name given to the bonds that are formed in triglycerides?

Answer 5

Ester bonds, this reaction is called esterification. Esterifications is another example of a condensation reaction.

Question 6

What is the difference between saturated and unsaturated?

Answer 6

Fatty acid chains that have no double bonds present between the carbond atoms are called saturated, because all the carbond atoms form the maximum number of bonds with hydrogen atoms. Fatty acids with double bonds between carbon atoms are unsaturated: -one double bond = monounsaturated -two or more double bonds = polyunsaturated

Question 7

What is the effect of the prescence of a double bond?

Answer 7

Causes a kink or bend, they therefore cannot pack so closely together, this makes them a liquid at room temperature rather than solid. Therefore they are usually described as oils.

Question 8

What is a phospholipid?

Answer 8

Modified triglycerides and contain the element phosphorus along with carbon, hydrogen and oxygen.

Phosphat eions (PO₄^3-) are found in the cytoplasm of every cell. Extra electrons, making them soluble in water.

One of the fatty acid chains in a triglyceride molecule is replaced with a phosphate group to make a phospholipid.

Question 9

What is unusual about phospholipids?

Answer 9

Due to their length, they have a non-polar end, or tails (the fatty acid chains) and a charged end or head (the phosphate group)

hydrophobic / hydrophillic

Question 10

How does this make them interact with water differently?

Answer 10

They will from a layer on the surface of the water with the phosphate head in the water and the fatty acid tails sticking out the water, because of this they are called surface active agents or sufacants for short.

they can also form a bilayer

important role in membranes