DNA Flashcards
DNA
Long chains of nucleotides
Made of phosphates,sugar,bases
Two chains run antiparallel in opposite directions
5’ sugar has a phosphate
Double helix, t pairs with a c pairs with g
DNA
DNA replication
Makes more dna
Occurs in nucleus
Occurs during a phase of interphase before mitosis and meiosis
DNA replication is semi conservative
One old stand one new strand
many enzymes work together to copy dna
DNA replication
Helicase
Unwinds dna(separates) by breaking hydrogen bonds
Topoisomerase
(Person standing on black lines)
Holds dna so it doesn’t retwist
Primase
Adds rna primer to start replication ,shows dna polymerase where to attach
DNA polymerase
Removes primer and adds can nucleotides in 5 to 3 direction also proofreads to catch errors and mutations
Leading strand
Made continuously, dna polymerase moves toward helicase as strands are separating
Lagging strand
Made in pieces( Okazaki fragments) bc dna polymerase can only add nucleoTides to growing 3’ end
Ligase
Seals together fragments on lagging strand
Uses dna to make mRNA so that the instructions in dna can be brought to the Protien building machinery outside the nucleus, occurs in nucleus of eukaryotic cells
Transcription
RNA
Single stranded, contains U uracil can be inside or outside nucleus
Helicase
Separates 2 strands of dna by breaking hydrogen bonds , uses in transcription
RNA polymerase
Build s mRNA using dna template used in transcription
Gene
Piece of dna that is use to make mRNA in a protiem
Promoter
Start of gene tells rna polymerase where to start
Terminator
End of a gene, tells rna polymerase where to stop