BioChem Lecture 7_Mutation and DNA repair Flashcards
(15 cards)
Define polymorphism
polymorphism is a genetic varient that occures in at least 1% of a population. The definition is independent of functional or pathogenic relevance of the alteration.
What are the 2 main types of polymorphisum?
Single nucleotide polymorphisum (aka point mutation) and indels (aka insertion/deletion mutations)
Define a point mutation
It is a mutation in which a single base base pair is changed
Define silent mutation
it is a mutation that still specifies the same amino acid (a point mutation that still codes for a particular AA)
Define missense mutation
a mutation that changes the AA being coded for in a single location (like sickle cell anemia). This may or may not have clinical significance.
Define Nonsnese mutation
A nonsense mutation is one that produes a premature stop codon
Define insertion/deletion mutation
This mutation inserts or deletes one or more base pairs. This shifts the reading frame for translation and is typically very detrimental
What are the two types of point mutations and what do they do?
Transition - One purine is changed for the other purine or one pyrimidine is changed for the other pyrimidine
Transversion - Purines and Pyrimidines are interchanged in the mutation
What are the three trinucleotid repeat diseases Dr Devska wants you to know
Huntington disease, Fagile X syndrome, and Myotonic dystrophy
Describe what causes Huntington Disease
36 or more CAG trinucleotide repeats in the HTT gene
Describe what causes fragile X syndrome
200 or more CGG trinucleotide repeats in the FMR1 gene
What causes myotonic dystrophy
trinucleotide repeats, not sure how many
List some of the endogenouse sources of DNA damage
Mistakes during replication, tautomeric shifts
List some of the exogenouse sources of DNA damage
Ionizing radiation, Hydrocarbons, ROS, Chemotherapy, etc.
List the four types of DNA repair
Proof reading
Mismatch repair
Excision repair
dsDNA repair
