Compléter DNA replicationVersion en ligne Complete this fill in the blanks activity par Belinda Schirmer 1 deoxyribose two four replicate G purine weak hydrogen proteins phosphate pull nitrogenous pyrimidines adenine antiparallel C Each nucleotide consists of three parts - a , a sugar ( sugar in DNA , Ribose sugar in RNA ) and a base . There are types of nitrogenous bases , and each nucleotide is named after the base that it carries - , thymine , guanine or cytosine nucleotides . These are often simply referred to by their first letters - A , T , G and C . A and are the larger double - ringed bases and and T are the smaller single - ringed bases . Each DNA molecule is made up of chains or strands that have an arrangement - that is , they are parallel but run in opposite directions . Each strand is made up of a sequence of many nucleotides , and the strands are held together by weak bonds between the bases in the centre of the DNA molecule . The advantage of these hydrogen bonds is that little effort is required to the bases apart so that DNA can or be decoded to form . 2 uracil pyrimidine base alternating RNA phosphate cytosine replication unzip ribose The vertical sides of the ladder are made up of sugar and phosphate molecules ( a sugar backbone ) and the 'rungs' of the ladder are pairs of a purine base linked to a base : adenine - thymine ( A - T ) and guanine to ( G - C ) . The bases are attached to the backbone through the sugar component . Bases are arranged in a sequence along each strand of DNA and the length of the DNA molecule is presented as the number of pairs ( bp ) . The two strands of DNA ( weak hydrogen bonds break ) for and gene expression . RNA is a single stranded molecule made of nucleotides , with a sugar attached to each phosphate to form the backbone ; on the other end it attaches to a base , either A , U , C or G . does not have thymine which is replaced by the base ( U ) . 3 template semi mutagens polymerases complementary read conservative 'proof enzymes proteins daughter unzip The two DNA strands for replication . DNA are complex that move along the DNA molecule linking nucleotides to their base partners to make new DNA chains . Each strand of DNA is used as a to make a new complementary strand . This is known as - DNA synthesis . Accurate DNA replication is important so that the cells have exact copies of the genetic information for synthesising . Some DNA polymerase enzymes have the ability to and edit' the DNA , correcting its own errors . There are also complex enzymes to repair other damage to DNA caused by . 4 functioning meiosis expression mitosis Heredity sexual maintenance accurately instructions survival Accurate DNA replication is important for two main reasons . : The genetic material of a cell must be transmitted from : a ) one cell to another during , allowing growth , repair and of an Organism . b ) one generation to another during , e . g . , when gametes are formed for reproduction . Gene : the genetic material of a cell must be transmitted accurately to give the correct to a cell to ensure the correct structure , and behaviour of an organism , essential for its . 5 continuity traits harmful variation advantage mutation evolution parent Genetic relies on : consistent replication of genetic information that is passed on from a cell to daughter cells , resulting in continuity in the being passed from parent to offspring . The effect of natural selection and on the gene pool as a result of : a ) introduction of during sexual reproduction . b ) random errors arising by being replicated and passed on to offspring . Random variations that confer an may be selected over those that confer no advantage or are .
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