DNA

Shireen Rudina

ingegneria biologica

Equipe de dibattito

DNA is the basis of life

• In every living organism, every cell

• In eukaryotes, found in the nucleus as chromatin

Why is DNA important?

• Forensics and paternity tests

• Personalized medicine

• Gene therapy

• Explains the differences between species and individuals

What are some of the barriers we need to break to extract DNA?

1. Cell wall

2. Ribosome

3. Golgi complex

4. Nuclear membrane

5. Cell membrane

4 DNA Nucleotides

Erwin Chargaff

• Analyzed the four nucleotides• In DNA of ANY species:– amount of A always equals amount of T– same with G and C

Rosalind Franklin

• X-ray crystallographer• Nobel Prize went to Watson and Crick• The X-ray diffraction image of DNA she made

was used (stolen!) by Watson to prove the 3D structure of DNA

Double Helix- Watson & Crick

Helix with Legos

• Red=A

• Blue=C

• Green=G

• Yellow=T

Why can’t you see the double helix in the DNA we extracted?

1. The extraction was incorrect.

2. The double helix is microscopic (very small)

3. There are not double helices in the chromatin

DNA StructureShape= Double Helix

Antiparallel

Sugar-Phosphate backbone- phosphodiester bonds (covalent)

Complementary base pairs (Chargaff’s Rule) - hydrogen bonds

A=T CΞ G

If one strand of DNA is ACCTGG, what is the complementary strand?

1. TGGCTT

2. ACCTGG

3. TGGACC

4. CTTGCC

The sequence of bases is important

• It is a code!• It codes for proteins, which perform all the

functions of the body

What is the monomer of proteins?

1. Amino acids

2. Nucleotides

3. Sugars

4. Phospholipids

20 amino acids

START

Why is it beneficial for DNA to be double stranded?

Why is the sequence important?

• Everyone’s is different

• Restriction enzymes cut at different points

Murder Case