IGCSE›Cambridge IGCSE Biology›Mind mapsChromosomes, Genes and ProteinsCambridge IGCSE Biology: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsKey termsChromosomes are made of DNAA gene is a length of DNA coding for a proteinAn allele is an alternative form of a geneSex chromosomesFemales are XXMales are XYGene to proteinBase sequence sets amino acid sequenceAmino acid sequence sets protein shapeShape determines functione.g. enzyme active site, antibody binding siteGenesand proteinsXXXYMaking a proteinGene stays in the nucleusmRNA copy is made in the nucleusmRNA moves to the cytoplasmmRNA passes through a ribosomeRibosome assembles amino acidsGene expressionMost body cells have the same genesOnly some genes are expressedRed blood cell: haemoglobinWhite blood cell: antibodiesExam tipsGive the full chain: bases → amino acids → shape → functionDNA controls enzymes, carriers and receptors