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STARTER . You are about to see an animation on protein structure

STARTER . You are about to see an animation on protein structure. Try and match the following key terms with the definitions given -primary structure -secondary structure -tertiary structure -quaternary structure - alpha helix -beta pleated sheet. Learning Objectives. Everyone should

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STARTER . You are about to see an animation on protein structure

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  1. STARTER. You are about to see an animation on protein structure Try and match the following key terms with the definitions given -primary structure -secondary structure -tertiary structure -quaternary structure -alpha helix -beta pleated sheet

  2. Learning Objectives Everyone should • Statefour functions of proteins, giving a named example of each Most will • Outlinethe difference between fibrous and globular proteins, with reference to two examples of each protein type. Some might • Explainthe significance of polar and non-polar amino acids. • Explainthe four levels of protein structure, indicating the significance of each level.

  3. Starter – TeamActivity Youhave 5 min to complete Steps A and B of Proteinmodellinghandoutonyourbench in teams • Alina and Lucia • Andrea , JP and Natalia • Work in a team BUT complete yourownhandout INDIVIDUALLY

  4. Learning Objectives Everyone should • Statethe four levels of protein structure Most will • Describe the four levels of protein structure, indicating the features of each level. Some might • Explainhow polar and non-polar amino acids determine the folding of a polypeptide to produce a functional protein

  5. Primarystructure of a protein • To simulate a protein, you will make a model of your protein using plasticine beads • Refer to the sequence of 15 amino acids (the colored circles on Step C of your worksheet) Complete Step C firstifyouhaven’talreadyusingthe amino acid chart provided • Arrange beads of the appropriate colors on the pipe cleaner. (substitute yellow for green) • The beads should be approximately evenly spaced the along the pipe cleaner.

  6. Secondarystructure of a protein • Twist one half of your protein model around a pencil to make a spiral. • Bend the other half of your protein molecule into a zig-zag shape by making a bend in the opposite direction at each bead. • Make a drawing to show the secondary structure of your protein model (Step D of your worksheet). • Label the alpha helix region and the beta-pleated sheet region on your drawing.

  7. TertiaryStructure • Twist your protein into a 3-D shape according to the protein folding ruleson the chart • Make a drawing to show the tertiary structure of your protein model (Step D of your worksheet). • Note: Do the best you can to make your 2-dimensional drawing look like your 3D model.

  8. QuarternaryStructure • Some protein chains are attracted to other protein chains. • Work with the other team and try putting your protein model next to their protein model in a way that still follows the rules of protein folding. • Make a drawing to show the quaternary structure of your protein model (Step D of your worksheet).

  9. Plenary – Ticket toExit! • Filloutyourtablewithoutusingyour notes • Try and incorporate as manykeytermsfromthetopic as you can

  10. PLENARYExplainthe four levels of protein structure (10) • primary structure is sequence / number of amino acids; • determined by base sequence in the gene; • (largely) determines higher level structures/secondary structure/tertiary structure; • secondary structure is regular repeating patterns; • such as alpha/α helix and beta/β (pleated) sheet; • determined by H bonds (within chain); • tertiary structure refers to overall 3-D shape; • conformation can determine function; • tertiary structure determined by R-group interactions / ionic interactions /hydrophobic interactions / disulfide bridges / H-bonds; • quaternary structure is only found in proteins formed from more than onepolypeptide; • e.g. hemoglobin; (accept other suitable example)

  11. Starter– sortthestatementsintoyourtable (q7)

  12. Learning Objectives Everyone should • Statefour functions of proteins, giving a named example of each Most will • Outlinethe difference between fibrous and globular proteins, with reference to two examples of each protein type. Some might • Explainthe significance of polar and non-polar amino acids in biological molecules

  13. GROUP ACTIVITY: Usingyourwhiteboards – can youdraw a diagramtoexplainhowthey do this?

  14. Nowlets try somePPQs (Q9-11) Forquestion 11.c – pleasechangethewordCHANNELtothewordMEMBRNE

  15. Mark scheme 9. Describe a polar molecule. Has charge 10. In the space below, draw and annotate a simple diagram to explain how polar molecules aid enzyme function.

  16. 11. a) The hydrophobic tails of the plasma membrane reject polar molecules: they do not allow them to pass through the membrane into or out of the cell. Define hydrophobic. Lacksanaffinityforwater b) Identify labels I to IV as being polar or non-polar. polar polar Non-polar Non polar

  17. c) Using the diagram, explain the significance of polar molecules in MEMBRANEproteins. (8) • membrane is a lipid bi-layer; • membrane has hydrophobic interior / lipid hydrophobic tails oriented inward; • hydrophilic on cytoplasmic and extracellular side / lipid hydrophilic heads oriented • outward; • polar amino acids are hydrophilic/water soluble/attracted to outside of membrane; • non-polar amino acids are hydrophobic/attracted to inside of membrane; • integral proteins embedded in the membrane; • peripheral proteins associated with surface of membrane; • non-polar amino acids cause proteins to be embedded in membrane; • polar amino acids cause parts of proteins to protrude from membrane; • transmembrane proteins have both polar and non-polar amino acids; • polar amino acids create channels through which (hydrophilic) substances/ions • can diffuse;

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