Lesson 2

Slide 2.1

Special Skin Cells Make Melanin

body

epidermis

How is melanin made inside the melanocytes?

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epidermis

melanocytes

tissue

cells

Lesson 2

Slide 2.2

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Skin Colors Cross Section of Skin Tissue

Melanocyte

Melanin

Lesson 2

Slide 2.3

Looking inside a melanosome

Oxygen

DOPA

Tyrosine

First step in making melanin:Reaction between two molecules, one tyrosine and one O2 to make DOPA

O O

O

Lesson 2

Slide 2.4

Tyrosinase(enzyme)

Skin cell

•

nuc Oxygen

Tyrosine

O O

Lesson 2

Slide 2.5

Tyrosinase(enzyme)

Skin cell

•

nucDOPA

O

Other enzymes turn help turn DOPA into melanin.

Lesson 2

Slide 2.6

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

Lesson 2

Slide 2.7

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

Lesson 2

Slide 2.8

Looking inside small intestine cells

Small intestine cells

lactose

galactose glucose

Lesson 2

Slide 2.9

Looking inside small intestine cells

Small intestine cells

lactoselactase

Lesson 2

Slide 2.10

Looking inside small intestine cells

Small intestine cells

galactose

glucoselactase

Lesson 2

Slide 2.11

Lactase

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Lesson 2

Slide 2.12

Protein Structure

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amino acidChain of

amino acids

Whole protein

Lesson 2

Slide 2.13

Protein Models

Cartoon model Space-filling model Toober model

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Lesson 2

Slide 2.14

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Modeling Lactase

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Lesson 2

Slide 2.15

Key to Toobers Blue=positive charge (+)

K, R, HRed=negative charge (-)

D, EYellow=hydrophobic

A, V, L, I, P, M, F, WGreen=hydrophilic

G, S, T, N, Q, YWhite = cysteine

C