4.3 fats

Question 1

what is another term for fats?

Answer 1

lipids

Question 2

what atoms are contained in fats?

Answer 2

carbon; hydrogen; oxygen

Question 3

how many molecules is fat made up of?

Answer 3

four smaller molecules joined together

Question 4

what makes a fatty acid?

Answer 4

three long molecules attached to glycogen

Question 5

how much energy does a gram of fat give?

Answer 5

39kJ

Question 6

what are the functions of fats?

Answer 6

storing energy; insulating the body; releasing energy (though in most cases carbohydrates>fats, hence storing energy)

Question 7

define adipose tissue

Answer 7

tissues made up of cells in which fat is stored

Question 8

how is energy stored?

Answer 8

some cells, particularly the ones under the skin, become filled with large drops of fat or oil, which can later be used to release energy when required.

Question 9

why do many plants store oil in their seeds?

Answer 9

oil provides a good store of energy for germination

Question 10

how to test for fats and oil?

Answer 10

using the ethanol emulsion test

Question 11

what are the steps of the ethanol emulsion test?

Answer 11

1. chop up food
2. shake it up with ethanol
3. pour ethanol into water
   - if there were fats in the food, the ethanol mixture would break up into millions of tiny droplets when mixed with water (emulsion); would look white and opaque (milky)
   - if no fats are contained, mixture remains transparent