Special Skin Cells Make Melanin

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Special Skin Cells Make Melanin
body
tissue
epidermis
melanocytes
epidermis
cells
How is melanin made inside the melanocytes?
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Melanin
Skin Colors
Cross Section of Skin Tissue
Melanocyte
3
Looking inside a melanosome
Oxygen
Tyrosine
DOPA
First step in making melanin Reaction between
two molecules, one tyrosine and one O2 to make
DOPA
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Tyrosinase(enzyme)
Tyrosine

Oxygen
nuc
Skin cell
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Tyrosinase(enzyme)

nuc
DOPA
Skin cell
Other enzymes turn help turn DOPA into melanin.
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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

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Cells in Small Intestine Break Down Lactose
Lactose from diet
Lactose brought into intestine cells
intestine cells
small intestine
Lactose broken down
How is lactose broken down in intestine cells?
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Looking inside small intestine cells
lactose
galactose
glucose
Small intestine cells
9
Looking inside small intestine cells
lactase
lactose
Small intestine cells
10
Looking inside small intestine cells
lactase
glucose
galactose
Small intestine cells
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Lactase
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Protein Structure
Chain of amino acids
amino acid
Folded chain of amino acids
Whole protein
13
Protein Models
Cartoon model
Space-filling model
Toober model
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Modeling Lactase
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Key to Toobers
Bluepositive charge () K, R, H Rednegative
charge (-) D, E Yellowhydrophobic A, V, L, I,
P, M, F, W Greenhydrophilic G, S, T, N, Q,
Y White cysteine C