Essential Idea: Proteins have a very wide range of functions in living organisms.




spider web with water droplets
A spider’s web made of silk, an extremely strong protein!

Q1+2: Choose the correct words to complete the following sentences:  
Polypeptides are chains of joined together by condensation reactions.
The bond between two adjacent amino acids is called a .

3. The general formula for an amino acid is NH2CHRCOOH.
Which groups are used in forming the peptide bond?

  • A. R group and amine group
  • B. R group and carboxyl group
  • C. Amine group and carboxyl group
  • D. Amine group and Hydrogen

4. How many different amino acids are there?

  • A. 51
  • B. 49
  • C. 98
  • D. 102

5. All the proteins produced by a cell, tissue or an organism is called a...

  • A. genome
  • B. ribosome
  • C. nucleus
  • D. proteome
6. The protein, haemoglobin, consists of ...
  • A. one polypeptide
  • B. three polypeptides
  • C. three amino acids
  • D. four polypeptides

7. Which of the following is not a globular protein?

  • A. Insulin
  • B. Rubisco
  • C. Collagen
  • D. Haemoglobin
8. Insulin consists of 2 polypeptide chains, the A chain made up of 21 amino acids and the B chain made of 30 amino acids. The two chains are linked by 2 disulphide bridges between cysteine residues. How many peptide bonds are in two molecules of insulin?
  • A. 51
  • B. 50
  • C. 100
  • D. 21

9. Proteins denature when heated.

The albumen of the white of the fried egg has denatured on heating. This happens because ...

fried egg
  • A. charges between R groups are changed
  • B. an increase in vibrations break intermolecular bonds
  • C. a decrease in vibrations causes intermolecular bonds to form
  • D. amino acids are lost from the protein structure

10. Which protein would increase when a person’s immunity to a disease is increased?

  • A. Haemoglobin
  • B. Collagen
  • C. Immunoglobulin
  • D. Insulin