DNA: deoxyribonucleic acidIt looks like a double-helix

found by Watson and Crick in 1953

DNA is packed in nucleus of cells

DNA is the blueprint of life

Interesting facts!One DNA molecule in a human cell is 1 meter long while diameter of the cell’s nucleus is 1/10^5 meterA-T; G-C in a double-helix DNA, so if the sequence of one strand is known, we can find the sequence of the other

All living things, including kiwi fruit, are made up of cells.

Step 1: Break down cell membrane and nucleus membrane

Step 2: Filter solution containing DNA out of cell debris

Step 3: Precipitation DNA out of the solution

Nucleus

Lysis solution made of washing up liquid and salt

Filter by coffee filter paper

Ice-cold 95% alcohol

Nucleus Cell membrane

Nucleus membrane

Cell organells

Extraction DNA from kiwi fruits

The salt stabilises the DNA so it does not break down when you extract it. It does this by providing positive charge to neutralise the natural negative charge of DNA.

The cell membrane is essentially a lipid (fat) bilayer (2 layers). The washing up liquid breaks this bilayer into small fat droplets. When this happens the cell contents are released.

All the insoluble parts of the fruit (cell walls etc.) are removed so we are left only with the cell contents, i.e. mainly DNA, amino acids and RNA. Remember it is the DNA we are interested in.

DNA is soluble in water, but not in alcohol. When alcohol is added, the DNA molecule becomes insoluble and precipitates out of the solution, becoming visible as a white stringy solid, between the alcohol (less dense) and water (more dense) layers.

So…how exactly does it work?All living things, including kiwi fruit, are made up of cells.

Step 1: Break down cell membrane and nucleus membrane

Step 2: Filter solution containing DNA out of cell debris

Step 3: Precipitation DNA out of the solution

Nucleus

Lysis solution made of washing up liquid and salt

Filter by coffee filter paper

Ice-cold 95% alcohol

Nucleus Cell membrane

Nucleus membrane

Cell organells