DNA structure: Inheritance, variation and evolution: Biology: GCSE (9:1)

• DNA


  Chemical molecules found in every living organism that hold instructions for growth and development

  
• Gene


  A small section of DNA that controls a specific characteristic by coding for a specific protein

  
• Polymer


  A material such as DNA that is made of very large molecules that are composed of many smaller repeating subunits

  
• Monomer


  A small repeating unit of a polymer such as the nucleotides that make up a DNA polymer

  
• Double helix


  The structure of DNA where two strands of DNA wind around each other like a twisted ladder

  
• Nucleotide


  A small structural unit of DNA, composed of a common sugar and phosphate group with one of four different bases attached to the sugar

  
• Bases


  A specific organic section of a nucleotide that contains nitrogen, there are four different types of bases in a DNA polymer

  
• C, G, A and T


  The letters that represent the four different types of bases found on a strand of DNA

  
• Sugar in DNA

  Also called deoxyribose sugar, the sugar joins with a nitrogenous base and a phosphate group to make a nucleotide

  
• Phosphate group


  Makes up the backbone of the DNA structure by joining with the sugar group in an alternating sequence

  
• Sugar-phosphate backbone


  An important structural component of the DNA strands, made up of alternating sugar and phosphate sections

  
• Repeating nucleotides

  The DNA polymer is made up of repeating nucleotide units with different arrangements of the bases C, G, A and T

  
• Sequence of three bases

  The code for an amino acid also called a codon or triplet, this arrangement of three bases leads to the formation of a specific amino acid

  
• Amino acids

  The building blocks of proteins, the sequence of amino acids determines the structure of the overall protein

  
• Proteins

  Building blocks of cells and tissues, made up of amino acids

  
• Applications of proteins

  Cell formation, enzymes, antibodies, haemoglobin, hormones, muscles, collagen in bones and connective tissue

  
• Protein synthesis


  Each gene codes for a particular sequence of amino acids which makes up a specific protein