DNA uppbyggnad Flashcards
Beskriv de fyra strukturnivåerna av nukleinsyra
Primärstruktur: Basernas ordning i 5’-3’
Sekundär: Ryggradens 3d konformation A, B eller Z
Tertiär: Molekylernas supercoiling-negativ eller positiv
Kvartär: Nukleinsyrornas interaktioner med proteiner, kromatin eller ribosom
Describe the common nucleobases
Purin: Adenine and guanine, two double rings
Pyrimidin: Cytosine, thymine and uracil, one ring
Remember less common nucleobases exist in tRNA, rRNA ~on RNA levels
What is the difference between a nucleoside and a nucleotide
Nucleosides encompass a nucleobase and a sugar molecule
Nucleotide has a nucleobase, sugar and a phosphate group
Name differences between DNA and RNA
DNA: uses T, has a deoxygroup, is more stable and is usually ds
RNA: uses U, has a OH group, less stable and can be ss or ds
Describe the central dogma
DNA is transcribed into RNA which is translated into proteins. The central dogma describes the flow of genetic information.
Describe forms of mutations
Substitution: base is swithced to another
Deletion: base is deleted
Insertion: base is inserted
Deletion and insertion will inevitably cause a frameshift
What is transition and transversion in substitution ?
Transversion is interchanfges of purine for pyrimidine bases; G/A-C/G
Transition is the change between purine or pyrimidine bases G-A or C-G
What can cause mutations ?
Spontaneous: depurination, deamination
Radiation UV: TT-dimers, 6,4 photoproduct
Replication errors
Chemicals: mustard gas, DMSO4, methylation
What are the effects of mutations ?
Silent mutation: codes for the same aa
Missense: codes for another aa that changes the protein for good or for worse
Nonsense: the aa change codes for stop and most likely results in termination
Frameshift: deletion or insertion
Splice site
Suppressor mutation: wrong + wrong=right, can happen.
