Download DNA (deoxyribonucleic acid) Model

DNA (deoxyribonucleic acid) Model
Materials: 2 pipe cleaners same color (red) for sugars (outside of helix)
4 different colored pipe cleaners (black, white, green, & brown)
to serve as adenine, thymine, cytosine, & guanine
metric ruler & scissors
Procedure:
1. Lay the 2 red colored stems on your desk to be the sides of the ladder.
2. Cut the 4 different colored stems into 7cm lengths to get 4 of each color.
3. Each color represents a different nitrogen base:
Black = adenine (A)
White = thymine (T)
Green = cytosine (C)
Brown = guanine (G)
4. Remember: cytosine is always paired with guanine; CG or GC
Adenine always pairs with thymine in DNA; AT or TA
5. Make a key on the paper provided that identifies which color represents which base.
6. Measure 2cm from the end of a black pipe cleaner, an adenine, and a white pipe cleaner, a
thymine. Twist them together, bending the ends back onto themselves. Keep the colors together
and not mixed at each junction.
7. Do this until you have constructed 6 rungs of the ladder, 3 with AT or TA and 3 with CG or GC.
Order is not important on the ladder or by letters for this exercise but it would be for real DNA.
8. Attach one side of a rung 4cm down on one side of the ladder before attaching the other side
4cm down on the other side of the ladder (red pipe cleaners). Measure 1.5 cm from the end of the
rung and wrap the end of the rung around the ladder side, bending the rung back on itself.
9. Slide a bead onto each ladder side, pushing it down until it meets the rung. The beads
represent the phosphate groups in the helix.
10. Repeat steps 8 & 9 until all rungs are attached. The ends of the ladder may have to be bent
back on themselves to keep the phosphates (beads) from falling off.
11. Now, carefully twist the entire ladder. The design shape is called the “double helix.”
12. Hole punch the key. Add your name and period. Attach to side piece of the ladder.
Name:__________________________ Date: ________________ Period: ____
Item represented:
Represented by this color pipe cleaner
Nitrogen Bases
Adenine
Black
Thymine
White
Cytosine
Green
Guanine
Brown
Item represented: Sugar (deoxyribose)
Red
Item represented: Phosphate group
White bead
Name:__________________________ Date: _________
Period: _______
Item represented:
Represented by this color pipe cleaner
Nitrogen Bases
Adenine
Black
Thymine
White
Cytosine
Green
Guanine
Brown
Item represented: Sugar (deoxyribose)
Red
Item represented: Phosphate group
White bead
Name:__________________________ Date: ________________ Period: ____
Item represented:
Represented by this color pipe cleaner
Nitrogen Bases
Adenine
Black
Thymine
White
Cytosine
Green
Guanine
Brown
Item represented: Sugar (deoxyribose)
Red
Item represented: Phosphate group
White bead
Name:__________________________ Date: ________________ Period: ____
Item represented:
Represented by this color pipe cleaner
Nitrogen Bases
Adenine
Black
Thymine
White
Cytosine
Green
Guanine
Brown
Item represented: Sugar (deoxyribose)
Red
Item represented: Phosphate group
White bead
Name:__________________________ Date: _________
Period: _______
Item represented:
Represented by this color pipe cleaner
Nitrogen Bases
Adenine
Black
Thymine
White
Cytosine
Green
Guanine
Brown
Item represented: Sugar (deoxyribose)
Red
Item represented: Phosphate group
White bead
Name:__________________________ Date: ________________ Period: ____
Item represented:
Represented by this color pipe cleaner
Nitrogen Bases
Adenine
Black
Thymine
White
Cytosine
Green
Guanine
Brown
Item represented: Sugar (deoxyribose)
Red
Item represented: Phosphate group
White bead