Do Now1. Take out last night’s homework so I can

check it.

2. Which of the following are probably carbohydrates?

A. C6H12O6 B. C6H14

C. C5H10O5 D. Xylose

E. Xylase1

ProteinsThis 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 kindof 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 whichsubstrates they bind.In other words,

They’re Specific.

15

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) 16

Busy Day Today

• Not a minute to waste!

• 1st: Write down tonight’s homework 3.11 – 3.18 Cornell notes

• 2nd: 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• 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!

21

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! 22

4 Levels of Protein Structure

23

To the Bat Cave (Teams!)

• We’ve got protein models to build!

24

Homework

• Sections 3.11-3.18

25