Biological molecules and food tests

Question 1

Carbohydrates contain?

Answer 1

C H O

Question 2

Proteins contain

Answer 2

C H O N

Question 3

lipids contain ?

Answer 3

C H O

Question 4

Maltose goes to

Answer 4

Starch

Question 5

Amino acids goes to

Answer 5

proteins

Question 6

glycerol and fatty acids goes to

Answer 6

lipids

Question 7

How to make a food sample

Answer 7

1. get a piece of food and break it up with a pestle and mortar
2. transfer food to beaker and add distilled water
3. stir mixture with glass rod to dissolve some food
4. filter solution using funnel and filter paper to get rid of solid.

Question 8

Glucose food test ?

Answer 8

Benedicts test

Question 9

Starch food test ?

Answer 9

Iodine solution

Question 10

Protein food test ?

Answer 10

Biuret test

Question 11

benedicts test

Answer 11

1. prépare food test and transfer 5cm3 to test tube.
2. prépare water bath at 75degrees.
3. add benedict solution (10 drops)
4. leave test tube in water bath for 5 minuted
5. if contains glucose - solution will change from blue to green/yellow in low conc amd brick red in high conc

Question 12

iodine solution test

Answer 12

1. make food sample and transfer 5cm3 to sample
2. add few drops of iodine solution and gently shake.
3. if sample contains starch - colour will change from browny orange to black or blue black

Question 13

biuret test

Answer 13

1. prépare sample and transfer 2cm3 to test tube.
2. add 2cm3 of biuret solution and mix contents by gently shaking.
3. if contains protein - colour change from blue to pink/purple

Question 14

lipid food test ?

Answer 14

sudan III Test

Question 15

sudan III test

Answer 15

1. prépare sample but don’t need to filter. transfer 5cm3 into test tube.
2. add 3 drops of sudan III stain solution and gently shake
3. if contains lipids - mixture will séparate into 2 layers. top layer will be bright red.