1. Question of the Day What does a positive test for a monosaccharide look like? What does a positive test for a polysaccharide look like? A positive test for a disaccharide? {see the NOTE sections in your last lab, at the bottom of pages 1 and 2}

2. Question of the Day: A monosaccharide turns Benedict’s solution from blue to orange after heating. A polysaccharide turns iodine from amber/ yellow to dark blue/black without heating. A disaccharide responds to neither Benedict’s nor iodine.

3. Proteins

4. Proteins are found in many foods. They make up muscle, skin, hair, nails, and control all the chemical reactions in your body.

5. Some other examples of proteins are Receptors and pores in the cell membranes Antibodies in the immune system, and neurotransmitters in the brain

6. AMINO ACIDS Proteins contain carbon, hydrogen, oxygen, & nitrogen. Some also contain sulfur. Their building block units are called “Amino Acids” There are only 20 amino acids in nature.

7. A dipeptide is two amino acids joined together through the removal of water

8. Many amino acids joined together make a polypeptide or protein. The average length of a protein is about 600 amino acids long.

9. Just like the 26 letters of the English alphabet can combine to make an almost infinite number of words

10. The 20 amino acids can combine to make an almost infinite number of proteins Hemoglobin, found in red blood cells, with a space in the middle to carry oxygen molcules

11. One kind of protein: Enzymes - large, complex proteins. Every particular chemical reaction in living things is facilitated by one particular enzyme. “Lock and Key” mechanism based on 3-D shape The molecule that is changed by the enzyme is called the substrate The place where the substrate attaches to the enzyme is called he active site Enzymes are biological catalysts; they help reactions happen and speed them up Enzymes are re-used over and over again Name ends in –ASE (Lactase breakds down Lactose)

12. Example: Lactose Intolerance Lactose is a sugar found in most milk products Lactase is an enzyme that breaks down lactose People who are missing lactase (can no longer produce it) can’t eat lactose unless they get artificial lactase.

13. Enzymes can be denatured (destroyed) by heat because the shape changes. Changing the pH can have a similar effect. Egg white protein is denatured by heat,

14. Table 4-1 Results of Tests with Known Carbohydrates Tube Number Carbohydrate Type Benedicts Color After Heating Iodine Color 1MonosaccharideOrangeAmber/ Yellow – no change 2DisaccharideBlue – no change Amber/Yell ow - no change 3PolysaccharideBlue – no changeBlue/ Black

15. Table 4-2 Results of Tests with Unknown Carbohydrates CarbohydrateHypothesis (Mono-, Di-, or Poly-) Benedict’s Color After Heating Iodine Color Type of Carbohydrate (after testing) HoneyOrangeAmber/ Yellow Mono – (fructose & glucose) OatsBlueBlue/ BlackPoly- (starch) Table SugarBlueAmber/ Yellow Di- (sucrose) Apple JuiceOrangeAmber/ Yellow Mono- (fructose) Powdered Sugar BlueAmber/ Yellow Di- (sucrose) Maple SyrupYellow/ green Amber/ Yellow Mono- (fructose) some Di- (sucrose)

16. Today we will be looking at an enzyme in your saliva, called salivary amylase. It breaks down starch into glucose molecules.

17. Investigation 4.5 You’ll be using the same testing methods as in lab 4.4 however you’ll do the lab in 3 Parts 1.Part A: Properties of Starch 2.Part B: Properties of Salivary Amylase (enzyme present in saliva – yes someone will be spitting, discreetly into a test tube!) 3.Part C: Properties of Starch Mixed with Salivary Amylase At each Part you’ll test with both Benedict’s (and heat) and iodine (no heat) and record your data.

18. SAFETY! No eating or drinking during the lab! Iodine and Benedict’s can stain and are both toxic! If you are the generous saliva donor, you will be the only one to handle, and wash your test tubes!

19. FIRST: Set up Part C – 1 st ! (it needs to sit for 15 minutes minimum!) Choose the person who hasn’t eaten something sugar in the last hour. READ the background info to help you with the DQ and Analysis Questions Quiz on lab (open notes/open lab) Thursday!