Module+07+Nucleic+Acids+and+Proteins


 * __7.1 DNA structure__**

7.1.1 Describe the structure of DNA, including the antiparallel strands, 3’–5’ linkages and hydrogen bonding between purines and pyrimidines. 7.1.2 Outline the structure of nucleosomes. 7.1.3 State that nucleosomes help to supercoil chromosomes and help to regulate transcription. 7.1.4 Distinguish between //unique or single-copy genes// and //highly repetitive sequences// in nuclear DNA. 7.1.5 State that eukaryotic genes can contain exons and introns.


 * __7.2 DNA replication__**

7.2.1 State that DNA replication occurs in a 5’ → 3’ direction. 7.2.2 Explain the process of DNA replication in prokaryotes, including the role of enzymes (helicase, DNA polymerase, RNA primase and DNA ligase), Okazaki fragments and deoxynucleoside triphosphates. 7.2.3 State that DNA replication is initiated at many points in eukaryotic chromosomes.


 * __7.3 Transcription__**

7.3.1 State that transcription is carried out in a 5’ → 3’ direction. 7.3.2 Distinguish between the //sense// and //antisense// strands of DNA. 7.3.3 Explain the process of transcription in prokaryotes, including the role of the promoter region, RNA polymerase, nucleoside triphosphates and the terminator. 7.3.4 State that eukaryotic RNA needs the removal of introns to form mature mRNA.


 * __7.4 Translation__**

7.4.1 Explain that each tRNA molecule is recognized by a tRNA-activating enzyme that binds a specific amino acid to the tRNA, using ATP for energy. 7.4.2 Outline the structure of ribosomes, including protein and RNA composition, large and small subunits, three tRNA binding sites and mRNA binding sites. 7.4.3 State that translation consists of initiation, elongation, translocation and termination. 7.4.4 State that translation occurs in a 5’ → 3’ direction. 7.4.5 Draw and label a diagram showing the structure of a peptide bond between two amino acids. 7.4.6 Explain the process of translation, including ribosomes, polysomes, start codons and stop codons. 7.4.7 State that free ribosomes synthesize proteins for use primarily within the cell, and that bound ribosomes synthesize proteins primarily for secretion or for lysosomes


 * __7.5 Proteins__**

7.5.1 Explain the four levels of protein structure, indicating the significance of each level. 7.5.2 Outline the difference between fibrous and globular proteins, with reference to two examples of each protein type. 7.5.3 Explain the significance of polar and non-polar amino acids. 7.5.4 State four functions of proteins, giving a named example of each.
 * __7.6 Enzymes__**

7.6.1 State that metabolic pathways consist of chains and cycles of enzyme catalysed reactions. 7.6.2 Describe the induced-fit model. 7.6.3 Explain that enzymes lower the activation energy of the chemical reactions that they catalyse. 7.6.4 Explain the difference between competitive and non-competitive inhibition, with reference to one example of each. 7.6.5 Explain the control of metabolic pathways by end-product inhibition, including the role of allosteric sites.