DNA: The molecule Year 10 Human Biology

DNA Deoxyribonucleic Acid An AMAZING molecule! Found in all living things Determines the characteristics of all living things

What’s the structure? The building blocks of DNA are called NUCLEOTIDES Phosphate group Deoxyribose sugar Nitrogen rich base Adenine Thymine Guanine Cytosine

How does it all go together? The shape of the DNA molecule is a double helix – or a twisted ladder The uprights of the ladder are alternating groups of sugar and phosphates The rungs are pairs of nitrogen rich bases

What goes with what? The nitrogen rich bases pair up in a very specific way Adenine pairs with Thymine Guanine pairs with Cytosine This is called the COMPLIMENTARY BASE PAIR RULE

Where can you find DNA? It is found in the nucleus of cells DNA can also be found in the Mitochondria – although the structure of mitochondrial DNA is different to nucleic DNA.

So what are chromosomes? Chromosomes are threadlike structures that are made up of the DNA molecule and protein molecules.

Have you heard of genes? Genes are located on chromosomes. Chromosomes are made up of DNA. So what is the relationship between genes and DNA? A gene is a section of DNA that contains the information for a protein.

Tell me more??! There are thousands of genes that produce all the proteins required for the human body to function. Genes differ from each other in the order and number of nucleotides.

So who discovered it? James Watson and Francis Crick are credited with the discovery of DNA in 1953 HOWEVER… Levene discovered the components of DNA and the nucleotide Avery proved that DNA holds the genetic code (1943) Chargaff determined the complimentary base pair rule (1940’s) Franklin discovered the double helix shape (1950’s)