Biomolecules

Question 1

What are the 3 biomolecules?

Answer 1

Proteins, carbohydrates, lipids

Question 2

What are the chemical elements that you can find in the corresponding biomolecules?

Answer 2

Carbohydrates= carbon, hydrogen, oxygen
Protein= carbon, hydrogen, oxygen, nitrogen, sometimes sulphur
Lipid= carbon, hydrogen, oxygen

Question 3

What are macromolecules and polymers?

Answer 3

A macromolecule can be described as a large molecule.
A polymer is a type of macromolecule made out of many of the same repeated units, called a monomer, bonded by covalent bonds.

Question 4

Give 3 examples of monomers.

Answer 4

Glycogen, cellulose, starch

Question 5

What are the processes that can bond monomers into polymers and break down polymers into monomers?

Answer 5

To bond to monomers to make a polymer, condensation occurs, which results in the removal of a water molecule.

To break down a polymer into single monomers, hydrolysis occurs, which results in the addition of a water molecule.

Question 6

What are monosaccharides, disaccharides and polysaccharides, and what are examples of each?

Answer 6

Monosaccharide= A single unit (a monomer)
-eg, glucose
Disaccharide= 2 monosaccharides joined together by condensation.
-eg, maltose
Polysaccharide= many monosaccharides joined together by condensation.
-eg, starch

Question 7

Talk about examples of carbohydrate monosaccharides, disaccharides and polysaccharides.

Answer 7

-Monosaccharides are glucose or fructose
-Disaccharides are maltose, lactose and sucrose
-Polysaccharides are starch and glycogen

Question 8

What is the structure of fat or oil called?

Answer 8

Triglyceride, with one glycerol molecule and 3 fatty acid molecules.

Question 9

What are the uses of fats?

Answer 9

-Concentrated energy source
-Insulation for animals

Question 10

Talk about amino acids.

Answer 10

-Monomer of a protein
-Bonded with peptide bonds

Question 11

What are the functions of proteins?

Answer 11

-Form enzymes
-Make up the substance in spider webs
-Used by all animals, for example, in the form of keratin (hair, wool, hooves, beaks, feathers etc)

Question 12

Explain the experiment to test for reducing sugars in a solution.

Answer 12

Add the solution in question to a test tube.
Add some benedict solution.
Put the test tube in a water bath of 80-100 degrees celsius.
If the solution remains blue, there are no reducing sugars, if the colour changes, there are reducing sugars.

Question 13

Explain the experiment to test for the presence of starch in a solution.

Answer 13

Add the solution in question to a test tube.
Add some iodine solution.
Close and shake gently
If there is starch, it will turn dark blue. If there isn’t, it’ll be red.

Question 14

Explain the experiment to test for fats and oils in food.

Answer 14

Add some ethanol to a small sample of a food.
Grind the mixture into a paste.
Filter it through filter paper.
Add the filtrate to some water.
If the solution is cloudy, it contains oil. If it’s clear, it doesn’t.

Question 15

Explain the experiment to test for protein in a food sample.

Answer 15

Place a small sample of the food in a test tube.
Add some biuret solution
Close and shake the solution.
If there is protein, the mixture will be purple. If there isn’t, the mixture will be blue.