Do Now 1.Take out last night’s homework so I can check it. 2.Which of the following are probably carbohydrates? A.C 6 H 12 O 6 B. C 6 H 14 C.C 5 H 10 O 5 D. Xylose E. Xylase 1

Proteins This is the enzyme we’ll be using in a lab later this week. What do you think it looks like? 2

Proteins have many different functions and structures. Proteins do most of the “work” a cell needs to stay alive! 3

Proteins are macromolecules made up of amino acids. 4

There are 20 different amino acids commonly found in nature. 5

Proteins are complex molecules 6

Here’s an amino acid *Hydrogen atoms not shown Forms 2 bonds to other amino acids. Called peptide bonds This part is different for each kind of amino acid. 7

Peptide bonds form by a dehydration synthesis reaction – JUST LIKE POLYSACCHARIDES! 8

Proteins are made of 1 or more polypeptides (polypeptide = single chain of amino acids) 9

Pectinase is the protein we’ll be using in the lab. 10

Pectinase attaches to pectin at the active site… 11

…And then breaks a bond in the polysaccharide! 12

Many proteins (like Pectinase) are enzymes. Enzymes speed up all different kinds of reactions! 13

ENZYME SUBSTRATE 14

SUBSTRATE Enzyme Enzymes are very selective about which substrates they bind. In other words, They’re Specific. 15

Protein Structure Protein structures are described on 4 levels of organization. –Primary (1 o ) Structure = sequence of amino acids: Ala-Glu-Asp-Ser… –Secondary (2 o ) Structure = how the sequence coils and folds due to hydrogen bonds –Tertiary (3 o ) Structure = the specific 3D shape of a single polypeptide –Quaternary (4 o ) Structure = how several polypeptides interact to make a complete protein (not all proteins have 4o structure) 16

Busy Day Today Not a minute to waste! 1 st : Write down tonight’s homework 3.11 – 3.18 Cornell notes 2 nd : get out notes outline from yesterday about protein structure 17

Review of Key Ideas Proteins are macromolecules made of many amino acids. A polypeptide is a chain of amino acids bonded together. A protein is made of 1 or more polypeptides. Proteins have many MANY important functions, including their job as enzymes which speed up chemical reactions. A protein’s shape, or structure, determines its properties 18

Primary Structure The primary structure of a polypeptide is simply the sequence of amino acids that it is made of 19

Secondary Structure Secondary structure describes how certain parts of a polypeptide coil or fold together to make specific shapes. 20

Tertiary Structure 3 o structure is the 3D shape of a polypeptide (polypeptide = a single chain of amino acids) A protein’s function depends a lot on its shape! 21

Quaternary Structure 4 o structure of a protein describes how multiple polypeptides come together to form a complete protein ATP Synthase: The protein that makes ATP! 22

4 Levels of Protein Structure 23

To the Bat Cave (Teams!) We’ve got protein models to build! 24

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