1. Slide 2.1 Lesson 2 Special Skin Cells Make Melanin body epidermis How is melanin made inside the melanocytes? epidermis melanocytes tissue cells

2. Slide 2.2 Lesson 2 Skin Colors Cross Section of Skin Tissue Melanocyte Melanin

3. Slide 2.3 Lesson 2 Looking inside a melanosome Oxygen DOPA Tyrosine First step in making melanin: Reaction between two molecules, one tyrosine and one O 2 to make DOPA O O

4. Slide 2.4 Lesson 2 Tyrosinase (enzyme) Skin cell nuc Oxygen Tyrosine O

5. Slide 2.5 Lesson 2 Tyrosinase (enzyme) Skin cell nuc DOPA O Other enzymes turn help turn DOPA into melanin.

6. Slide 2.6 Lesson 2 Lactose intolerance Cannot break down lactose, a disaccharide found in dairy products Instead, bacteria in the intestine break down the lactose, producing gas Most children can break down lactose Most adults in the world cannot break down lactose - making them lactose intolerant

7. Slide 2.7 Lesson 2 Cells in Small Intestine Break Down Lactose intestine cells How is lactose broken down in intestine cells? small intestine Lactose from diet Lactose brought into intestine cells Lactose broken down

8. Slide 2.8 Lesson 2 Looking inside small intestine cells Small intestine cells lactose galactose glucose

9. Slide 2.9 Lesson 2 Looking inside small intestine cells Small intestine cells lactose lactase

10. Slide 2.10 Lesson 2 Looking inside small intestine cells Small intestine cells galactose glucose lactase

11. Slide 2.11 Lesson 2 Lactase

12. Slide 2.12 Lesson 2 Protein Structure Folded chain of amino acids amino acid Chain of amino acids Whole protein

13. Slide 2.13 Lesson 2 Protein Models Cartoon modelSpace-filling modelToober model

14. Slide 2.14 Lesson 2 Modeling Lactase

15. Slide 2.15 Lesson 2 Key to Toobers Blue=positive charge (+) K, R, H Red=negative charge (-) D, E Yellow=hydrophobic A, V, L, I, P, M, F, W Green=hydrophilic G, S, T, N, Q, Y White = cysteine C