GV2: Mutations Flashcards
what are inherited diseases
mutations in genes encoding for essential functional proteins
what is cancer
mutations in genes encoding for proteins involved in the regulation of growth and survival
what are polymorphisms
different gene sequences which can cause altered phenotype function but not necessarily disease
what are alleles
genes encoding different polymorphic forms of proteins
what are the four normal control mechanisms
heterozygosity, apoptosis, cell cycle control, regulation of gene transcription
what is heterozygosity
two copies of genes to minimise loss of function due to mutations
what is apoptosis
damaged cells killed to prevent transmission of mutated genes
what is cell cycle control
checkpoints during cell division to ensure cell is healthy, no damaged DNA
what is regulation of gene transcription
requirement for appropriate activation signals to induce gene expression
how could sequence mutations change ‘normal’ genes into ‘aberrant’ genes
deletions or insertions might scramble the encoded mRNA leading to complete loss of functional protein
single base mutation could lead to a single amino acid difference in the altered protein which could lead to a change in functional activity
what are two examples of monogenic inherited diseases
cystic fibrosis, sickle cell anaemia
what causes cystic fibrosis
deletion of phenylalanine - causing incorrect folding and subsequent degredation
what causes sickle cell anaemia
SNP of the beta-globin gene, glutamic acid substituted by valine
what are oncogenes
mutated forms of normal cellular genes (proto-oncogenes) which control cell growth
usually dominant - only need mutation in one allele to increase function
what do oncogenes encode for
growth factors, receptors, signal transducers, nuclear transcription factors
