Lecture 4- Mutations Flashcards
Define Mutation and describe the different types of mutations listed and the resultant consequences in
transcription and translation.
Base Pair Substitution
Mutation: damage or alteration in DNA sequence programming –> can result in permanent alterations of proteins
Leads to:
a) Diminished function of that protein
b) If it is a stem cell, it can cause dysfunction of that tissue
c) If the mutation is in the germ line cells, it can effect all the offspring
d) It can have absolutely no effect
Base pair substitution - could be addition or deletion of a base pair causing a frame shift mutation and a different protein
–> could also be harmless
Define Mutation and describe the different types of mutations listed and the resultant consequences in
transcription and translation.
Silent base pair substitution
No harm!
The addition of deletion coded for the original amino acids it was intended for.
This is due to the redundancy of the universal code
Or the substitute occurred in an intron which is removed by RNA splicing.
Define Mutation and describe the different types of mutations listed and the resultant consequences in
transcription and translation.
Base pair insertion
This causes a frameshift mutation which offsets the entire DNA sequence in the gene programming the protein
Define Mutation and describe the different types of mutations listed and the resultant consequences in
transcription and translation.
Base pair deletion
Causes a reading frame shift which offsets the entire DNA sequence in the gene programming the protein.
Define Mutation and describe the different types of mutations listed and the resultant consequences in
transcription and translation.
Translocation
During crossing over, the ends of one chromosome is exchanged for the end of a non-homologous chromosome
Define Mutation and describe the different types of mutations listed and the resultant consequences in
transcription and translation.
Fragile Sites
Also known as mutational hot spots
These are areas where spontaneous mutation occurs
–> certain areas of chromosomes have a high mutation rate; this is evidenced by mutation suddenly appearing in an individual or in a family pedigree that has never been there before
Define Mutation and describe the different types of mutations listed and the resultant consequences in
transcription and translation.
Non-disjunction
Failure of chromosomes to separate or sister chromatids to separate during mitosis or meiosis
Define a mutagen and list 12 different mutagens that could lead to the mutations in objective 1. Describe a
“Mutational Hot Spot”.
Mutagens:
a) ionizing radiation
b) cigarette smoke
c) cresol from bbq meats
d) saccharin
e) sodium nitrate
f) nitrogen mustard
g) vinyl chloride
h) formaldehyde
i) UV light
Mutational Hot spot
- -> areas of chromosomes that are more likely to mutate and cause spontaneous mutations
- -> evidenced by mutations that appear in family pedigrees
What is an autosome v. an allosome?
Autosome - not a sex chromosome
Allosome - sex chromosome
–> monosomy of allosome is not lethal unlike autosome
What is complete dominance verse incomplete dominance?
Complete dominance is when both dominant alleles are expressed and not mixed
–> ex) two cows have a baby
the mom cow is white
the dad cow is red
baby will express a mix of both white and red, the colors didn’t mix into a pink color, both colors are expressed
Incomplete dominance is when both dominant alleles are expressed but mixed
–> ex) red and white flower cross pollinate
their offspring is pink!
the dominant alleles were mixed rather than each separately expressed
