DNA and the production of proteins

every chromosome in the nucleus contains DNA DNA is made up of two strands twisted around each other , called a double helix  each strand is made up of many repeating building blocks  called nucleotides

each nucleotide is made up of a deoxyribose sugar, a phosphate group and a base (adenine, thymine, guanine and cytosine) each strand is held together by weak hydrogen bonds between the bases the sugar and phosphate form the back bone of the double helix the bases are linked in specific pairing or complementary pairings

adenine - thyminecytosine - guanine the sequence of bases is responsible for the types of proteins made in cells

reactions controlled by enzymes enzymes are made of protein built p from units called amino acids enzymes are biological catalysts  responsible for function, growth and development of cells and organisms the sequence of bases determines the sequence of DNA each triplet of bases is called a codon 

Mrna is made up of one strand of DNA and Mrna carries the genetic info to the cytoplasm to make proteins  Mrna is single stranded and contains the base uracil instead of thymine 

structure of DNA

DNA and protein