2.1.3 Nucleotides and Nucleic Acids Flashcards
(14 cards)
what are the similarities and differences between dna replication and transcription?
similarities —
• both involve unwinding of DNA
• strands act as template strands
differences —
• both involve complimentary base pairing
• in replication both strands act as templates but only one in transcription
• in dna replication, new dna strands stay in nucleus
• transcription uses RNA polymerase but dna replication uses DNA polymerase
how is hydrogen bonding important in DNA?
- holds two polynucleotides together by complimentary base pairing
- stabilises DNA
what does RNA polymerase do?
- initiates transcription
- joins RNA nucleotides together
why is it important new DNA is identical to old DNA?
- new one should be genetically identical
- minimises risk of mutations
why is it important for codons to be universal?
genetic information can be transferable between species
what is the practical for purifying DNA with a precipitation reaction?
- break up cells using a blender
- make up a solution of detergent, salt and distilled water
- add broken cells into a beaker containing detergent solution and incubate in water bath at 60 degrees for 15 mins
- put beaker in ice bath to cool the mixture. filter and transfer into clean boiling tube
- add protease enzymes to break down proteins
- dribble cold ethanol down side of tube, DNA will form a white precipitate
how does pairing of bases allow identical copies of dna to be made?
- A and T join together and C and G join together
- they make H bonds
- purine can bind w pyrimidines as they are different sizes
why does ATP not last in the body long?
- used immediately
- ATP broken down to ADP
what’s the significance of a template strand in transcription?
complimentary mRNA nucleotides attach to it
what’s the significance of RNA polymerase?
- initiates transcription
- catalyses formation of phosphodiester bonds
how does the structure of DNA facilitate semi conservative replication?
- both strands act as a template strand
- purine binds to pyrimidine
- free nucleotides pair with both strands
why is replication being semi conservative important?
- so genetically identical
- reduce chance of mutations
what’s the structural diff between pyrimidines and purines?
- purines have double carbon ring structure
- pyrimidines have single carbon ring structure
how would you do chromatography of a substance
- break named substance into their named substrates
- place sample on chromatography paper
- dry and repeat
- place paper in solvent
