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Welcome Back! February 27, 2012. Sit in any seat for today. You will have assigned seats tomorrow Were you absent before the break? Plan on coming to tutorial today or tomorrow to makeup the test (from Thursday), it must be completed by Tuesday in tutorial.
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Welcome Back!February 27, 2012 • Sit in any seat for today. You will have assigned seats tomorrow • Were you absent before the break? Plan on coming to tutorial today or tomorrow to makeup the test (from Thursday), it must be completed by Tuesday in tutorial.
Open Logbook…do you have an entry from Friday before break? • Entry10: Proteins Beginning Ideas
Make an entry- Entry 11. Proteins: Amino Acids in 3 D- 2/27/12
2 Types of Proteins 1) Structural – proteins that form physical parts. Examples – -keratin (hair and nails) -actin (muscle) -microtubules (cell membrane skeletons) - gelatin - collagen
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
Protein Shape Determines Function Example – Fibrous proteins are long and thin, and are used for structure
What will we learn today? HOW is the shape of a protein determined?
Proteins are made ofchains of amino acids What are amino acids? Link to amino acid 3-D models
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
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
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
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
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
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
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
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
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
Amino Acids Model activity Peptides are chains of amino acids and sometimes used as another word for protein. 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