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FRIDAY 10/2 DUE BY 4 PM TODAY: • • MC Corrections (Google Classroom) Intro to Biomolecules Activity (Google Classroom) This week at a glance: • Quiz on Wednesday Over: Water, Intro to Biomolecules, Protein • Vocabulary is due on Thursday 10/8 This will go on next grading period • Friday: LAST DAY OF THE GRADING PERIOD Friday is also early release Friday is also pajama day!!!! Oh, and you have a 3 day weekend.
Today’s essential learning: (This is a question or task you should be able to complete after we take notes today. You need to write it at the top of your notes page. ) Explain three factors that can determine the 3 D structure, and thus function, of a protein.
Bio-molecule: Proteins • A protein is a large, complex polymer composed of elements: carbon, hydrogen, oxygen, AND nitrogen. • Proteins make up more than 50% of the dry mass of most cells.
• The monomer (small subunit molecules) of proteins are called amino acids. • There are 20 amino acids that can (in various orders and lengths) make literally thousands of different kinds of protein chains.
Remember this? ? ?
Side Group (R) carbon Amino group Carboxyl group hydrogen
The side ‘R’ group can be as simple as a lone hydrogen atom- or complex, being a carbon skeleton with more functional groups attached.
Some Side ‘R’ groups are Hydrophobic…. Glycine (Gly or G) Methionine (Met or M) Alanine (Ala or A) Valine (Val or V) Phenylalanine (Phe or F) Leucine (Leu or L) Tryptophan (Trp or W) Nonpolar, Repel Water Isoleucine (Ile or I) Proline (Pro or P)
Some Side ‘R’ groups are Hydrophilic…. Serine (Ser or S) Threonine (Thr or T) Cysteine (Cys or C) Tyrosine (Tyr or Y) Asparagine Glutamine (Asn or N) (Gln or Q) Polar and Attract Water
Some Side ‘R’ groups are Charged and also Hydrophilic Acidic Aspartic acid Glutamic acid (Glu or E) (Asp or D) Basic Lysine (Lys or K) Electrically Charged and attract water Arginine (Arg or R) Histidine (His or H)
How are proteins built? =
How are proteins built? DEHYDRATION SYNTHESIS Loss of water To build/ put together
Bonds in a protein: peptide bond The bonds that are created after dehydration synthesis that hold amino acids together in a protein are called PEPTIDE BONDS.
Remember this? ? ?
4 7 2 5 8 3 6 9 1
peptide bond A bunch of amino acids bonded together makes a polymer chain called a poly-peptide. One or more poly-peptide chains- folded, twisted, and coiled into a particular shape is a complete protein.
Polypeptide Chain Protein
• The sequence of amino acids will ultimately determine a protein’s three-dimensional structure • A protein’s structure determines its function
Fig. 5 -20 Antibody protein Protein from flu virus
Degrees of Protein Structure Proteins have four steps that lead to its final structure. Primary Degree of Structure: The order of amino acids in the chain. The primary structure is like the order of letters in a long word. Remember, this sequence is determined by your DNA.
Secondary Degree of Structure: Backbone- Spirals and Pleats • The coils and folds of secondary structure result from hydrogen bonds between repeating constituents (not the R groups) of the polypeptide backbone. • Typical secondary structures are a coil called a helix and a folded structure called a pleated sheet
Tertiary Degree of Structure: Side ‘R’ Groups- Big Folds • Tertiary structure is determined by interactions between R groups, rather than interactions between backbone constituents
Possible Quarternary Degree of Structure: Binding with other polypeptide chains • Quaternary structure results when two or more polypeptide chains form one macromolecule • Collagen is a fibrous protein consisting of three polypeptides coiled like a rope • Hemoglobin is a globular protein consisting of four polypeptides: two alpha and two beta chains