Biology Test 4 DNA + Protein Synthesis

mRNA

mRNA

messenger RNA, brings DNA coding out of nucleus to ribosome (where proteins are built)

rRNA

combines w/ proteins to make ribosomes

tRNA

carries amino acids to ribosomes and matches up to specific codons

ribozymes/RNase

RNA can act as an enzyme (this enzyme will reassemble/refine mRNA and get rid of unwanted RNA) (RNA spliceosomes are a subset of RNase)

initiation (transcription)

RNA polymerase unwinds DNA chain, transcribes DNA to RNA w/ base pairs

elongation (transcription)

RNA polymerase follows from 5’ to 3’ and lengthens the new RNA

termination (transcription)

RNA polymerase reaches stop codon and releases, winds DNA, and stops transcription

initiation (translation)

Ribosomes begin translation upon reaching a start codon, tRNA with anticodon delivers the amino acid

elongation (translation)

Next tRNA comes into ribosome and bonds its amino acid, then ribosome moves and repeats

termination (translation)

When the ribosome reaches a stop codon, it releases polypeptide and mRNA

Promoter

DNA segment that recognizes RNA polymerase, promotes transcription

operator

DNA segment, binding site for repressor protein, blocks RNA polymerase

structural gene

code for particular proteins

inducer/repressor

Binds to or removes repressor proteins from operator

repressor protein

Protein that represses the actions of RNA polymerase and stops transcription

epignetic control

Uncoils DNA and loosens it from histones (wrapped DNA can’t allow RNA polymerase)

transcription control

Turns mRNA formation on and off (most common), similar to operons

post-transcription control

Processes pre-mRNA into mature mRNA, mature mRNA that is functional is necessary

translation control

Regulates rate of initiation (how fasts ribosomes move, how many tRNA molecules are available)