Study BMB 400 Chapter 15 Flash Cards

Pile Management Card
BMB 400 Chapter 15

standard genetic code

-widespread but not universal
-ex: RNA derived from mito DNA

genetic interaction

-product of mutated gene interacts with the original product
-2 genes don't physically interact

supressing frameshift mutations

-if deletion occurs, add a nucleotide!
-aka suppressor of frameshift mutation
-can be different codon or different gene!

frameshift

-insertion/deletion that changes reading frame

nonsense

-cause abrupt termination

missense

-replacement of 1 aa

nonsilent

-do change aa
-non-degenerate positions
-likely subject to evolutionary selection

silent mutation

-does not change aa
-occur in degenerate positions
-most frequent b/c don't really matter
-used for adjusting GC% of genomes

pairings

G: U or C
C: G
A: U
U: A or G
I: A, U, or G

inosine

deamination of adenosine
-enzymatic rxn

61 codons can be read by ___ tRNAs

evidence: higly purifed tRNAs could recognize >1 codon

wobble base

-last codon (of 3' end)
-first anticodon (of 5' end)

are all codons used euqally?

Hellz to the NO!
-pattern of usage corresponds to species/tissues

purine in the 2nd position

-usually hydrophilic aa's

pyrimidine in 2nd position

-usually hydrophobic aa's

change 1st codon...

...will give you a similar aa

degeneracy

-almost all aa's are encoded by multiple codons
-found primarily in 3rd position

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