causes of genetic mutations Flashcards
what are point mutations?
changes in a single base
what are silent mutations?
triplet codon changes but the amino acid doesnt
what are the types of missense mutations?
conservative
non-conservative
what are conservative mutations?
changes in the triplet change the amino acid but its chemically similar
what are nonconservative mutations
changes in the triplet codon change the amino acid and it isnt chemically similar
what are nonsense mutations?
leads to premature stopping of the amino acid sequence by coding for a stop codon
what is a frameshift mutation?
where a single base is added or deleted from the DNA sequence - changes the reading frame
what are the types of chromosomal mutations?
deletions
duplications
inversions
translocations
what are chromosomal inversions?
when part of a chromosome breaks off and its added on backwards
what are chromosomal translocations?
when part of a chromosome breaks off and attaches to a different chromosome
what is an example of a disease caused by a frameshift mutation?
Tay Sachs
give examples of chromosomal mutations
Cri du chat - partial short arm deletion
Di George syndrome - partial long arm deletion
Charcot Marie Tooth disease - duplication
XX male syndrome - translocation
Turners - monosomy
Klinefelters - non-disjunction
what causes genetic mutations
spontaneous
induced (environment)
what are mutagens?
agents that cause genetic mutations
give examples of mutagens
phyical - UV light, radiation and heat chemical - nicotine, pesticides and methane biological - bacteria and viruses radiation - direct and indirect smoking infectious agents
what infectious agents can cause disease and what disease do they cause?
HPV - cervical cancer
Helicobacter pylori - stomach cancer
give an example of a point mutation
sickle cell anaemia
what mutation occurs in sickle cell?
glutamic acid –> valine
what is non-disjunction?
when chromosomes fail to separate properly
what is the only monosomy to produce viable offspring?
turner’s
what happens in XX male syndrome?
Translocation of SRY gene from Y chromosome to X chromosome
what spontaneous mutations can occur?
depurination - loss of purine base
deamination
tautomeric shift - repositioning of H atom
what effect can direct radiation have?
forms a pyrimidine dimer
what indirect effect can radiation have?
creation of free radicals
