DNA Flashcards
What is replication?
DNA is created in a semiconservative process using existing strands as templates. (for cell replication)
What is transcription?
RNA is created in the nucleus using DNA strands as templates.
What is translation?
ribosomes create proteins using RNA strands as templates.
What is mRNA?
contains codon for amino acids
What is tRNA?
delivers amino acids to ribosome
What is rRNA?
component of the ribsome
Which nucleotides are pyrimidines?
C,T
Which nucleotides are purines?
G,A
Which nucleotides have 3 H-bonds?
C,G
Which nucleotides have 2 H-bonds?
A,T
Where does the next nucleotide add in a DNA chain?
at the 3’ OH
How are the two chains of DNA held together?
H-bonds between nitrogenous bases.
In which direction is DNA read? and by what?
3’ to 5’
DNA polymerase
In which direction are nucleotides added?
How is this accomplished in the lagging strand?
5’ to 3’
lagging strand (3’ to 5’) is created with (5’ to 3’) okazaki fragments that are later spliced together.
What is involved in post-transcriptional RNA processing?
1) 5’ cap is added
2) exons are spliced out
3) 3’ poly-A tail is added
What are the three steps of translation?
Initiation: small subunit + tRNA binds to mRNA at start codon; then large subunit joins.
Elongation: new tRNA brings next amino acid; ribosome moves to next codon.
Termination: Ribosome reaches stop codon and releases mRNA and protein.
What is the start codon?
AUG Methionine
What are the stop codons?
UAA, UAG, UGA
What is the hybridizing character of the N in a peptide bond and why?
sp2
the bond between the carbonyl and the nitrogen is partially double-bond due to resonance (N donates lone pair to bond to create negative charge on O).
