1. Bonding A covalent bond is stronger and holds the atoms in a molecule together. A Hydrogen bond is weaker and it attracts molecules to one another.

2. Base Pairing Cytosine pairs with Guanine The 4 molecules in DNA are called bases or nucleotides Adenine pairs with Thymine

3. Bonding in DNA Hydrogen bonds (Weaker & can be separated) Covalent bonds (stronger & difficult to break)

4. Uniqueness The sequence..... Each sequence provides unique information about living organisms

5. Self-Assembly & Viruses

6. What is self- assembly? What does it mean to “assemble” something? Then what would “self-assembly” mean? Self-assembly is the spontaneous formation of patterns without direct manipulation. Scientists do this mainly by exploiting the ways that molecules attract or repel each other without external manipulation, and by adjusting their physical environment.

7. Self-assembly at very small scales Patterns self-assembled from the interactions of particles. Scientist don’t put the particles right next to each other or bond them by hand; the particles do this themselves. The scientist just creates the right environment.

8. Self assembly is based on components reorienting their physical positions due to attraction and repulsion forces. gold-polymer

9. Viruses (say: vy-rus-iz) Virus means toxin or poison Viruses are made of genetic material (DNA) They need to be inside living cells to grow and reproduce.

10. Virus Influenza Chickenpox Measles

11. Virus Structure A Virus consists of two parts: 1. Genetic material: single OR double DNA strand 2. Capsid: A coat that protects this genetic material

12. Finding a Virus So far we know..... Viruses are a long chain of nucleotides (A A T G C T A C T A C T A T......) Cytosine pairs with Guanine Adenine pairs with Thymine

13. Help Find a Virus! Your job: Catch the virus with 4 nucleotides Important: Make sure your catcher isn’t going to catch the non viral DNA! If we know how to pair the correct nucleotides (bases) we can find out if this is a virus

14. Virus: C T G T G T G G T C A A T T C T GG T T G G C T A C T G T G T G G T C A A T T C T A T A C T G C T ANon Virus:

15. Virus: C G A G A G C C A A G G G C A G A A T A A T T C G C G A G A G A A T G A G G C A G A A T A A T T C G Non Virus: