gene mutation 0.0 / 5 ? BiologyDNA, genetics and evolutionASEdexcel Created by: erinmcgarry3Created on: 17-01-19 19:56 what is a mutation? a permanent change in the DNA of an organism; if a single codon is changed or misread during protein synthesis entire protein will be altered 1 of 26 when can they happen? gametogenesis and division of somatic (body) cells 2 of 26 what is thalassaemia? blood proteins not manufactured correctly 3 of 26 what is cystic fibrosis? membrane protein does not function properly 4 of 26 what are gene mutations? involve changes in the bases making up the codons 5 of 26 what is the chance of a mutation taking place in during DNA replication? 2.5 x 10⁻⁸ per base 6 of 26 what does the body produce to try and reduce mutation? specific enzymes that cut out or repair any part of the DNA strands that become broken or damaged 7 of 26 what is a point mutation? one or a small number of nucleotides are miscopied during transcription; gene mutations 8 of 26 what are the three types of point mutations? substitutions, insertions, deletions 9 of 26 what are substitutions? one base in a gene is substituted for another 10 of 26 what are insertions? an extra base is added into a gene, which may be a repeat or a different base 11 of 26 what are deletions? a base is completely lost 12 of 26 what are chromosomal mutations? changes in the position of entire genes within a chromosome 13 of 26 what are whole-chromosome mutations? entire chromosome either lost during meiosis or duplicated in one cell by errors in this process 14 of 26 what is an example of a whole-chromosome mutation? down's syndrome; chromosome 21 has three copies instead of two 15 of 26 what is a big advantage of mutations? causes genetic variation within an organism or species; new and superior protein 16 of 26 why are mutations a big risk? if the mutation occurs in enzyme formation and active site shape affected, effects catastrophic 17 of 26 what is sickle cell disease (sickle cell anaemia)? genetic disease that affects protein chains which make up haemoglobin in red blood cells; point mutation 18 of 26 what does this point mutation do to the haemoglobin? haemoglobin molecules stick together to form rigid rods that give red blood cells sickle shape 19 of 26 why is this bad? do not carry oxygen efficiently and block smallest blood vessels 20 of 26 what will happen to the person affected? severe pain and death 21 of 26 when do mutations most commonly occur? copying of DNA for cell division 22 of 26 what can happen if mutations happen in body cells? problems such as cancer 23 of 26 why are mutations in gametes the most devastating? because they will be passed on to offspring 24 of 26 what are mutagens? anything that increases the rate of mutation 25 of 26 what are some examples of mutagens? x-rays, ionising radiation, certain chemicals, tar 26 of 26
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