Lipids Flashcards
(20 cards)
What are lipids made up of?
Carbon, hydrogen, oxygen
-H:O=2:1
What are the properties of lipids?
- Insoluble in water
- Soluble in organic solvents, e.g. ethanol
What is the most common type of lipids?
Triglycerides
How is triclyceride formed?
One glycerol+three fatty acid by condensation
How can a triglyceride be broken down?
By hydrolysis
What are triglyceride in solid state called?
Fats
-Mainly from animals
What are triglyceride in liquid state called?
Oils
-Mainly from plants
What are food rich in fats and oils?
Fatty meat, seeds, nuts, milk, dairy products
What are the three main functions of lipids?
- As energy reserves
- As a shock absorber
- As a heat insulator
Where are lipids stored in?
Adipose tissues
Where can adipose tissue be found?
Under skin as subcutaneous fat or around internal organs
What much energy can one gram of lipids provide?
38.9 kJ
How does lipids act as a shock abosorber?
Fat stored in adipose tissues around internal organ act as a shock absorber to protect the internal organs
What is the use of subcutaneous fat in our body?
Act as a heat insulator to prevent heat lost if the body.
What can lipids help absorb, transport and store?
Lipid-soluble vitamins
-e.g. vitamins A and D
What can lipids produce?
Hormones
-e.g. Sex. growth hormones
What is a major component of cell membranes made of lipids?
Phospholipids
What is the test for lipids called?
Grease spot test
What is the positive result of the grease spot test?
A translucent spot will appear on the dried filter paper
What are the procedures of the test?
- Let a drop of food sample on a filer paper dry
- A translucent spot will remain if lipids is present
- Immerse the filer paper into organic solvent
- Take put the filter paper and the spot will disappear
