3.1.3-Lipids

Question 1

What is a triglyceride made from?

Answer 1

1 glycerol molecule and 3 fatty acids

Question 2

What is a phospholipid made of?

Answer 2

1 glycerol molecule, 2 fatty acids and a phosphate group

Question 3

Describe how a triglyceride molecule is formed

Answer 3

One glycerol and 3 fatty acids
condensation reactions and removal of 3 water molecules
Ester bonds formed

Question 4

What are the two types of fatty acid R-Group?
What are their definitions?

Answer 4

Saturated-The hydrocarbon chain only has single bonds between carbons
Unsaturated-The hydrocarbon chain consists of atleast one double bond between carbons

Question 5

What is the function of triglycerides and phospholipids?

Answer 5

Triglycerides-Energy storage
Phospholipids-Make up the cell membrane

Question 6

How do we test for lipids

Answer 6

Emulsion test
-Add ethanol
-Then add water
-Then shake
-Positive=milky white emulsion

Question 7

How are triglycerides related to their function?

Answer 7

-Insoluble meaning they won’t affect water potential
-Can store a lot of energy due to large ratio of energy storing carbon-hydrogen bonds compared to number of carbon atoms

Question 8

How are phospholipids related to function?

Answer 8

Have hydrophilic head (attract water) and hydrophobic tail (repel water)
In water arrange to phospholipid bilayer positioned so heads are exposed to water and tails are not

Question 9

the general structure of a fatty acid is RCOOH name the group represented by COOH

Answer 9

Carboxyl

Question 10

Compare and contrast the structure and properties of triglycerides and phospholipids

Answer 10

-Both contain glycerol
-Both contain ester bonds
-Both insoluble in water
-Triglyceride has 3 fatty acids phospholipid has 2 fatty acids plus phosphate group
-Triglycerides are hydrophobic phospholipids have hydrophobic and hydrophilic region