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 DID YOU MISS THE TEST BEFORE THE BREAK?

 DID YOU MISS THE TEST BEFORE THE BREAK? Today is the last day to make it up in tutorial. Open to yesterday’s entry- Entry 11. Proteins: Amino Acids in 3 D- 2/27/12 Let’s review what we talked about yesterday. 2 Types of Proteins.

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 DID YOU MISS THE TEST BEFORE THE BREAK?

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  1. DID YOU MISS THE TEST BEFORE THE BREAK? Today is the last day to make it up in tutorial. Open to yesterday’s entry- Entry 11. Proteins: Amino Acids in 3 D- 2/27/12 Let’s review what we talked about yesterday.

  2. 2 Types of Proteins 1) Structural – proteins that form physical parts. Examples – -keratin (hair and nails) -actin (muscle) -microtubules (cell membrane skeletons) - gelatin - collagen

  3. 2) Functional – Proteins that have activity Examples- -Hormones – used for signaling -Defensive – antibodies that recognize foreign invaders -Transport – Carrier proteins!!! -Enzymes – used for chemical reaction - Hemoglobin – found on RBC and carry oxygen

  4. Protein Shape Determines Function Example – Fibrous proteins are long and thin, and are used for structure

  5. What will we learn today? HOW is the shape of a protein determined.

  6. Proteins are made ofchains of amino acids What are amino acids? Link to amino acid 3-D models

  7. There are 20 different amino acids. All have the same general form. H O C C H2N Carboxyl group Amino group OH R Side chain Non-ionized form

  8. Each amino acid has a different side chain. H H H H H H O O O O O O C C C C C C C C C C C C H3N+ H2N+ H3N+ H3N+ H3N+ H3N+ O– O– O– O– O– O– CH CH2 H3C CH CH3 H H2C CH2 H3C CH2 CH3 CH CH2 CH3 H3C CH3 Alanine (A) Ala Isoleucine (I) Ile Glycine (G) Gly Valine (V) Val Leucine (L) Leu Proline (P) Pro Side chains contain carbon and/or hydrogen

  9. Each amino acid has a different side chain. H H H O O O H3N+ H3N+ H3N+ C C C C C C O– O– O– CH2 CH2 CH2 NH OH Phenylalanine (F) Phe Tyrosine (Y) Tyr Tryptophan (W) Trp Side chains contain ring structures

  10. Each amino acid has a different side chain. H H O O H3N+ H3N+ C C C C O– O– CH2 CH2 CH2 SH S CH3 Methionine (M) Met Cysteine (C) Cys Side chains contain sulfur

  11. Each amino acid has a different side chain. H H O O H3N+ H3N+ C C C C O– O– CH2 CH HO CH3 OH Threonine (T) Thr Serine (S) Ser Side chains contain hydroxyl functional groups

  12. Each amino acid has a different side chain. H H O O H3N+ H3N+ C C C C O– O– CH2 CH2 C CH2 O H2N C O H2N Asparagine (N) Asn Glutamine (Q) Gln Side chains contain amino functional groups

  13. Each amino acid has a different side chain. H H H O O O H3N+ H3N+ H3N+ C C C C C C O– O– O– CH2 CH2 CH2 NH CH2 CH2 +NH CH2 CH2 CH2 NH +NH3 +NH2 C NH2 Arginine (R) Arg Histidine (H) His Lysine (K) Lys Basic side chains

  14. Each amino acid has a different side chain. H H O O H3N+ H3N+ C C C C O– O– CH2 CH2 C CH2 O– O C O– O Aspartate (D) Asp Glutamate (E) Glu Acidic side chains

  15. Proteins are chains of amino acids H H O H H H O O O N C H2N + H2N H2N C C C + H2O C C C C OH OH OH Amino group H Peptide bond CH3 CH3 H Carboxyl group C-terminus N-terminus H O H H O H H O H H O H H O H H O H H O H H O H OH C H N C C N C C N C C N C C N C C N C C N C C N C CH3 CH2 CH2 H CH2 CH2 CH CH2 H3C CH3 OH OH C SH O OH N-terminus C-terminus COOH H2N Asp Phe Val Tyr Cys Gly Ala Ser 1 2 3 4 5 6 7 8

  16. Protein Model activity Peptidesare chains of amino acids and sometimes used as another word for protein. Get four amino acids per table (group of two) Follow the instructions of your teacher to build peptides using the paper amino acid models for questions #1-4. Then join your chain with another groups chain to form an 8 amino acid chain for #5

  17. Amino Acid sequence determines the 3-D protein shape • Interactions between amino acids cause folding and bending of the chain Examples: • positive (+) and negative (-) parts of amino acids are attracted to each other. • hydrophobic regions are attracted to each other • Sulfur is attracted to each other MUST be an amino acid between them to attach by paper clips COMPLETE #6-7

  18. Figure 3.11a Interactions that determine the structure of proteins H C O N Hydrogen bond between peptide groups O H3C CH3 (CH2)4 CH2CH NH3+ CHCH2 –O CCCH2 H3C CH3 OH CH2 O C Ionic bond Hydrogen bond between side chain and peptide group Hydrophobic interaction O H CH2 OH N CH2C CH2 S S CH2 H Disulfide bond Hydrogen bond between two side chains

  19. #8: CYS- LEU- ARG- GLY- GLY-GLY- ASP- LEU- CYS + S - S hydrophobic hydrophobic

  20. 9. HOW WOULD YOU BE ABLE TO BUILD A COMPLETELY DIFFERENT PROTEIN USING THE SAME 8 AMINO ACIDS? • You could change the order (sequence of the amino acids) which makes it a different shape (different protein).

  21. From yesterday: The shape of a protein determines its function. • Now we know…. The shape is determined by the sequence/order of amino acids and their interactions with each other.

  22. Make an entry- Entry 12: Lactose Intolerance- 2/28/12 See attached entry Read the information and answer questions on the worksheet. It will be homework if you don’t finish it.

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