DNA Structure

• DNA strands are polymers made up of lots of repeating units called nucleotides
• Each nucleotide consists of one sugar molecule, one phosphate molecule, and one base
• Each nucleotide consists of a common sugar and phosphate group with one of four different bases attached to the sugar
• DNA contains four bases, A, C, G, and T.
• A sequence of three bases is the code for a particular amino acid.
• The order of bases controls the order in which amino acids are assembles 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 phosphate bases.
• The DNA polymer is made up of repeating nucleotide units.
• In the complementary strands, a C is always linked to a G on the opposite strand and a T to an A
• Proteins are synthesised on ribosomes, according to a template. Carrier molecules bring specific amino acids to add to the growing protein chain in the correct order.
• When the protein chain is complete it folds up yo form a unique shape. This unique shape enables the proteins to do their job as enzymes, hormones or forming structures in the body such as collagen.
• Mutations occur continuously. Most do bot alter the protein, or only alter it slightly so that its appearance or function is not changed
• A few mutations code for an altered protein with a different shape. An enzyme may no longer fit 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 switch genes on and off, so variations in these areas of DNA may affect how genes are expressed.