2.3/2.4 - Carbohydrates, lipids and proteins
Assessment statements
DCS Topic Code | Statement | Guidance |
2.3.U1 | Monosaccharide monomers are linked together by condensation reactions to form disaccharides and polysaccharide polymers. | Sucrose, lactose and maltose should be included as examples of disaccharides produced by combining monosaccharides. The structure of starch should include amylose and amylopectin. |
2.3.U2 | Fatty acids can be saturated, monounsaturated or polyunsaturated. | Named examples of fatty acids are not required. |
2.3.U3 | Unsaturated fatty acids can be cis or trans isomers. | |
2.3.U4 | Triglycerides are formed by condensation from three fatty acids and one glycerol. | |
2.3.A1 | Structure and function of cellulose and starch in plants and glycogen in humans. | |
2.3.A2 | Scientific evidence for health risks of trans fats and saturated fatty acids. | |
2.3.A3 | Lipids are more suitable for long-term energy storage in humans than carbohydrates. | |
2.3.A4 | Evaluation of evidence and the methods used to obtain the evidence for health claims made about lipids. | |
2.3.S1 | Use of molecular visualization software to compare cellulose, starch and glycogen. | |
2.3.S2 | Determination of body mass index by calculation or use of a nomogram. |
DCS Topic Code | Statement | Guidance |
2.4.U1 | Amino acids are linked together by condensation to form polypeptides. | |
2.4.U2 | There are 20 different amino acids in polypeptides synthesized on ribosomes. | Students should know that most organisms use the same 20 amino acids in the same genetic code although there are some exceptions. Specific examples could be used for illustration. |
2.4.U3 | Amino acids can be linked together in any sequence giving a huge range of possible polypeptides. | |
2.4.U4 | The amino acid sequence of polypeptides is coded for by genes. | |
2.4.U5 | A protein may consist of a single polypeptide or more than one polypeptide linked together. | |
2.4.U6 | The amino acid sequence determines the three-dimensional conformation of a protein. | |
2.4.U7 | Living organisms synthesize many different proteins with a wide range of functions. | |
2.4.U8 | Every individual has a unique proteome. | |
2.4.A1 | Rubisco, insulin, immunoglobulins, rhodopsin, collagen and spider silk as examples of the range of protein functions. | The detailed structure of the six proteins selected to illustrate the functions of proteins is not needed. |
2.4.A2 | Denaturation of proteins by heat or by deviation of pH from the optimum. | Egg white or albumin solutions can be used in denaturation experiments. |
2.4.S1 | Drawing molecular diagrams to show the formation of a peptide bond. |
Notes

2.3/2.4_notes.pdf |
PlayPosits
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Review PowerPoints

2.3 and 2.4_carbslipidsproteins.ppt |

2.4_proteins.ppt |