Completar frases DNA and proteinsVersión en línea What can you remember? por Natalie Hodgson 1 protein disease genetic DNA shape enzymes amino double gene switch three treatment ribosomes sugar C amino chromosomes fit nucleotide genome four bases order G protein polymer bases The material in the nucleus of a cell is composed of a chemical called . DNA is a made up of two strands forming a helix . The DNA is contained in structures called . A is a small section of DNA on a chromosome . Each gene codes for a particular sequence of acids , to make a specific . The of an organism is the entire genetic material of that organism . The whole human genome has now been studied and this will have great importance for medicine in the future . The importance of understanding the human genome . For example : search for genes linked to different types of , understanding and of inherited disorders , use in tracing human migration patterns from the past . Students should be able to describe DNA as a polymer made from different nucleotides . Each nucleotide consists of a common and phosphate group with one of four different attached to the sugar . DNA contains four bases , A , , G and T . A sequence of bases is the code for a particular acid . The order of controls the order in which amino acids are assembled to produce a particular protein . The long strands of DNA consist of alternating sugar and phosphate sections . Attached to each sugar is one of the four bases . The DNA polymer is made up of repeating units . In the complementary strands a C is always linked to a on the opposite strand and a T to an A . Proteins are synthesised on , according to a template . Carrier molecules bring specific amino acids to add to the growing protein chain in the correct . When the protein chain is complete it folds up to form a unique . This unique shape enables the proteins to do their job as , hormones or forming structures in the body such as collagen . Mutations occur continuously . Most do not alter the protein , or only alter it slightly so that its appearance or function is not changed . A few mutations code for an altered with a different shape . An enzyme may no longer the substrate binding site or a structural protein may lose its strength . Not all parts of DNA code for proteins . Non - coding parts of DNA can genes on and off , so variations in these areas of DNA may affect how genes are expressed .