1. 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
Which of the following are probably carbohydrates?
C6H12O6 B. C6H14
C5H10O5 D. Xylose
E. Xylase

2. 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

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

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

5. 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.

6. 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.

7. Proteins are macromolecules made up of amino acids.

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

9. Proteins are complex molecules

10. 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.

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

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

13. 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?

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

15. Pectinase attaches to pectin at the active site…

16. …And then breaks a bond in the polysaccharide!

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

18. ENZYME
SUBSTRATE

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

20. 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

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

22. 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

23. 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)

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

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

26. 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!

27. 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!

28. 4 Levels of Protein Structure