D1.3: Gene Mutation Flashcards
Post-transcription
Mythlene cap + poly-A tail
Define proteosomes
Total protein material used in cell
- Recycles unused amino acid
Post-translation
what happens to polypeptides after translation
Describe the characteristics of the genetic code
- 64 codons
- universal
- 20 a.a.
Why do some mutations not result to structural changes?
Because of silent mutations
Give the two types of mutations
Base substitution and frameshift mutation
Define base substitution
aka point mutations
- substitution of 1 nitro base
Define gene mutation
permanent change in gene seq of DNA
Outline the three types of base substitution
- silent mutation: no noticeable effect on protein
- missense: maybe 1 change in aa
- nonsense mutation: change to early stop codon
Outline the two types of missense
- conservative - results in a functional protein
- non-conservative - now not functional
Define allele
versions of a gene (e.g. blue and brown eye color)
Define frameshift mutation
- occurs whentheres an insertion or deletion of a base
- affects how the genetic sequence is read
Which type of cell passes on mutations?
Gametes
How many mutations are there per generation
~100-200
Cause of sickle cell anemia
base substitution to the 6th codon for the beta chain of hemoglobin
-> for memory: CTC (velinxi) -> CAC (that one bruno mars dragon meme — jump in the cac)
Sickle cell consequences
- formation of fibrous haemoglobulin turns blood cell into sickle shape
- destroyed more rapidly -> low RBC count
- may form clots within capillaries
- shape not denatured but changed
- can return to high oxygen normal shape
Outline the types of mutagens
- physical - forms of radioation
- chemical - chemical substances (reactive oxygen series, metals like arsenic..)
- biological - some viruses and certain bacteria
Define block mutations
Changes to segments or a chromosome, resulting in large scale changes
Define transposons
Mobile genetic elements that can change positions in the genome
Outline the different types of block mutation
Where can mutations occur?
Anywhere but some placed have a higher probability of mutating
Why does mitochondrial DNA have a higher chance of mutation
Limited protection: Unlike nuclear DNA which is wrapped in a protective protein coat (histones), mtDNA is more exposed within the mitochondria. This lack of a shield makes it more susceptible to damage from ROS and other environmental factors.
Why can mutations be beneficial, detrimental or neutral?
No pre-determined direction, random chance
How does mutation act as a source of genetic variation?
Only source of new alleles in a population
- continuous variation and follow a normal distribution curve as the rate of change is gradual and cumulative
- ^ diversity ^ beneficial mutations via natural selection
What are the classifications of mutations?
- Somatic
- Germ-line
(depends in type of cell)
Define somatic mutations
Occur in a single body cell and cannot be inherited
- only tissue of origin of mutated cell
Germline mutations
occur in gametes and can be passed on to offspring
- affects every cell
