1. DNA presented by Mrs. Sanford 7th Grade Life Science
Lost Mountain Middle School

2. DNA (Deoxyribonucleic Acid)
a master copy of instructions for cell structure and function
compared to:
an agenda
a set of blueprints
an owner’s manual
chemical code

3. DNA (Deoxyribonucleic Acid)
chemical code
gives you your characteristics
- internal and external traits like hair color, eye color, height, heartbeat, hearing, personality, talents

4. DNA (Deoxyribonucleic Acid)
chemical code
organic compound
contains carbon
nucleic acid

5. DNA (Deoxyribonucleic Acid)
structure (what it looks like)
three dimensional
double helix
spiral staircase
twisted ladder

6. DNA (Deoxyribonucleic Acid)
structure
sides or “handrails” are made of sugars and phosphates
‘ribo’ is for ribose, a sugar

7. DNA (Deoxyribonucleic Acid)
structure
cross pieces, “rungs” or “steps” are made of nitrogen base pairs
same two bases always pair
adenine, thymine (A, T)
cytosine, guanine (C, G)

8. DNA (Deoxyribonucleic Acid)
discovery/history 1950’s
x-rayed by Rosalind Franklin
Rosalind Franklin
DNA X-ray

9. DNA (Deoxyribonucleic Acid)
discovery/history 1950’s -1960’s
Maurice Wilkins gives Franklin’s x-rays to Watson and Crick
Francis Crick and James Watson make a model of DNA

10. DNA (Deoxyribonucleic Acid)
discovery/history 1960’s
Franklin dies of cancer
Wilkins, Watson, and Crick share a Nobel Prize for the model

11. DNA (Deoxyribonucleic Acid)
DNA Model
Wilkins
Watson and Crick
DNA Model Sketch

12. DNA (Deoxyribonucleic Acid)
DNA replication
copying happens in the cell cycle during interphase
Watson and Crick also modeled this

13. DNA (Deoxyribonucleic Acid)
DNA replication
enzymes break apart the bases
RNA collects extra bases from the cytoplasm

14. DNA (Deoxyribonucleic Acid)
DNA replication
the extra bases pair with the broken DNA strands
new handrails form from sugars and phosphates

15. DNA (Deoxyribonucleic Acid)
DNA replication
two new strands have been created

16. DNA (Deoxyribonucleic Acid)
Mutation
damaged chromosomes (strands of DNA)
mistakes in the DNA

17. DNA (Deoxyribonucleic Acid)
Mutation
deleted or inserted base pairs, “steps”
example: albinism

18. What does DNA look like? Draw picture in the space to show what you think the structure of DNA looks like.
examples

19. What does DNA do? Draw picture in the space to show what you think the function (job) of DNA is.

20. Your Turn How is your model like the real DNA? How is it different?
Use the model kit to make a replica of DNA
Review kit colors
Same two bases always use same two colors
adenine and thymine (A, T)
cytosine and guanine (C, G)
How is your model like the real DNA?
How is it different?
Where is DNA found in cells?
What does it look like when inside the cell’s nucleus?