Biology · Form and function

B1.2 — Proteins

Biology · SL / HL · syllabus-mapped notes

1. B1.2.1

   Generalized structure of an amino acid

   Draw a generalized amino acid: alpha carbon with amine group, carboxyl group, R-group and hydrogen.

2. B1.2.2

   Condensation reactions forming dipeptides and longer chains of amino acids

   Write the word equation for condensation and draw a generalized dipeptide.

3. B1.2.3

   Dietary requirements for amino acids

   Distinguish essential from non-essential amino acids, and explain why vegan diets need planning.

4. B1.2.4

   Infinite variety of possible peptide chains

   Explain why the variety of peptide chains is effectively infinite, and name examples of polypeptides.

5. B1.2.5

   Effect of pH and temperature on protein structure

   Explain how pH and temperature denature proteins.

6. B1.2.6

   Chemical diversity in the R-groups of amino acids as a basis for the immense diversity in protein form and function

   Explain how R-groups determine a protein's properties, and how they divide by hydrophobicity and charge.

7. B1.2.7

   Impact of primary structure on the conformation of proteins

   Explain why the amino acid sequence determines a protein's precise, predictable three-dimensional shape.

8. B1.2.8

   Pleating and coiling of secondary structure of proteins

   Explain how hydrogen bonding stabilizes alpha helices and beta-pleated sheets.

9. B1.2.9

   Dependence of tertiary structure on hydrogen bonds, ionic bonds, disulfide covalent bonds and hydrophobic interactions

   Explain the four bonds holding tertiary structure, and how R-groups become charged.

10. B1.2.10

    Effect of polar and non-polar amino acids on tertiary structure of proteins

    Explain why hydrophobic amino acids cluster in a globular core, and form the membrane-embedded belt.

11. B1.2.11

    Quaternary structure of non-conjugated and conjugated proteins

    Explain quaternary structure using insulin and collagen (non-conjugated) and haemoglobin (conjugated).

12. B1.2.12

    Relationship of form and function in globular and fibrous proteins

    Contrast globular and fibrous protein shape, and relate each to function using insulin and collagen.