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.

Covalent bonds are strong bonds that hold atoms in a molecule together.

The electrons orbit around both nuclei, holding the atoms together.

A covalent bond happens between atoms that share electrons.

Which of these molecules will bond?

1

2

3

DNADeoxyribonucleic

Acid

DNA is in every Cell of living things

DNAWhy is DNA important

Chromosome

DNA is shaped like a double helix.

DNA structure

This is what DNA looks like. The white parts represent the two different strands. These

strands can be separated.

DNA STRANDS can be represented differently

DNA structure

Nucleotides

DNA

Nucleotides or Bases

GuanineThymine AdenineCytosine

The 4 molecules in DNA are called bases...

Each base has physical properties and they’re so small (0.33 nanometres)

nothing can see them

Base PairingCytosine

Base Pairing

Adenine

Guanine

Cytosine

Base Pairing

Thymine

Adenine

Guanine

Cytosine

Bonding in DNA

Hydrogen bonds(Weaker & can be

separated)

Covalent bonds(stronger & difficult to

break)

Uniqueness

The sequence.....

Each sequence provides unique information about living organisms

Base pairing

Next: Self-Assembly

&Viruses

What is self-assembly?

What does it mean to “assemble” something?

Then what would “self-assembly” mean?

Self-assembly at very small scales

Patterns self-assembled from the interactions of molecules.

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.

Virus examples

•Influenza

•Chickenpox

•Measles

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.

Base Pairing

Guanine

Cytosine

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

Finding a Virus

•So far we know.....C - GA - T

•Viruses are a long chain of nucleotides (A A T G C T A C T A C T A T......)

Help find the Virus!

?

Your job: Catch the virus with 4 nucleotides

Important: Make sure your catcher isn’t going to catch the non-viral

DNA strand!

? ? ?

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: