Biology DNA Flashcards
What are the 3 characteristics of DNA?
- able to store information
- stable replication
- undergo rare changes
Purine Nucleotides are?
double ringed
Pyrimidine nucleoties are?
single ringed
what does DNA helicase do?
separates double-stranded DNA into single strands
SSB-single stranded binding protien
binds to single-stranded DNA and prevents to from re-forming a double helix
DNA primase does what?
synthesizes short RNA primes
DNA polymerase does what?
synthesize DNA in the leading and lagging strands, removes RNA primers, filling the gaps with more DNA and proof-reads newly made DNA
parents strands are….
antiparallel to each other
DNA replication is a semiconservative process because?
each daughter strand contains a old strand from the parental DNA
DNA always occurs in the…
5 to 3
prokaryotic DNA replication….
can occur in two directions at once because the DNA molecule is circular
prokaryotic DNA is….
a single looped chromosome
prokaryotic DNA must be….
replicated before the cell can divide
what are the steps to prokaryotic DNA replication?
- the strands sperate and unwind
- a DNA enzyme binds to each side of the opening
- two DNA polymerase meet at the termination region and replication is stopped.
- two chromosomes are separated
Eukaryotic DNA replication brings
along the length of the linear chromosome
genetic coding is degenerate
most amino acids have more than one codon
redundancy of the code helps…
protect against potentially harmful mutations
genetic code is unambigous
each triplet codon has only one meaning
the code has how many start and stop signals
one start signal and 3 stop signals
what is the start signal?
AUG
what are the stop singals?
UAA / UGA / UAG
transcription is
DNA to RNA (writing across)
translation is
RNA to polypeptide (carry across)
what are the steps to transcription
- RNA polymerase attaches to a region of DNA promoter (defines the start, direction and the strand to be transcribed)
- RNA polymerase reads down the DNA strand 5’ to 3’ and stops once it reaches a DNA sequence.
- RNA polymerase stops transcribing and releases the mRNA transcript.
what are the steps to translation
- initiation- brings all the translation components together. tRNA pairs with the start codon (AUG)
- a polypeptide increases one amino acid at a time
- the polypeptide and assemble components are separated
