Do Now 10.14 OBJECTIVES: Identify the monomers and functions of proteins. Define enzyme and substrate. Identify and describe the 4 levels of protein structure. TASK: 1. HW check: “Carbohydrates,” pp. 55-56 Which of the following are probably carbohydrates? C6H12O6 B. C6H14 C5H10O5 D. Xylose E. Xylase

Macromolecules Chart: Carbohydrates Building Blocks: Monosaccharides Functions: Energy storage Types: mono-, di-, & polysaccharides Important Examples: Cellulose in plant cell walls, Glucose C6H12O6 Other notes: 1:2:1 ratio of C:H:O

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

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

Proteins can be structural or enzymes Collagen is an example of a structural protein: it is a connective tissue protein, making up much of the skin, tendons, and ligaments Structural proteins are building materials for cells and organisms.

Almost All Enzymes Are Proteins Enzymes are biological catalysts that speed up chemical reactions. Luciferase is an enzyme that breaks apart luciferin – making fireflies flash.

Proteins are macromolecules made up of amino acids.

There are 20 different amino acids commonly found in nature.

Proteins are complex molecules

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.

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

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

Do Now 10.16 Objective: complete previous Task: Amylase is an enzyme that breaks down (i.e. hydrolyses) the polysaccharide amylose (i.e. starch). What kind of macromolecule is amylase? What are the building blocks of amylase?

Pectinase is a protein that hydrolyzes the poly-saccharide Pectin.

Pectinase attaches to pectin at the active site…

…And then breaks a bond in the polysaccharide!

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

ENZYME SUBSTRATE

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

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

Catalase: The enzyme of next week’s lab 2 H2O2  2H2O + O2

Enzyme Recap Enzymes are almost always proteins. Enzymes speed up (catalyze) specific chemical reactions. Enzymes are reusable, and don’t participate in the chemical reactions they catalyze. Substrates are the chemicals an enzyme works on

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

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

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

Tertiary Structure 3o 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!

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

4 Levels of Protein Structure