transcription, translation, mutation Flashcards
protein synthesis
How cells follow DNA directions on how to make proteins
Each chain of nucleotides is a
line of code
Each chain of nucleotides contains
directions for making many different proteins
each set of directions is a gene
one gene= one protein= one trait
steps in making a protein
1) Copy the Directions for one protein onto RNA (one gene)
Transcription
2) Use the RNA directions to make a protein
Translation
Transcription
Copy the Directions for one protein onto RNA (one gene)
RNA polymerase scans the DNA to find the gene it needs to copy
mRNA carries coded directions out into cell where it binds to a ribosome
what four jobs does RNA polymerase do in in transcription
1) unwind the DNA double helix
2) breaks hydrogen bonds to separate chains
3) match RNA nucleotides to the DNA gene
4) fuse the RNA nucleotides together to make a chain of RNA
mRNA
The chain of RNA that is made is called mRNA
Or messenger RNA
Translation
Translates nucleotide code of RNA into
the amino acid code of a protein
translation takes place where and is done by what
Takes place in the cytoplasm
Is done by a ribosome
mRNA
chain of nuclotides that make up the coded directions for making the protein
codon
the code for one amino acid
Every 3 nuclotides of mRNA is a codon
ribosome structure
made of two subunits; large ribosomal subunit made of RNA and small ribosomal site made of proteins
how does process in ribosome start
Subunits bind onto mRNA chain at start codon (P)
how many codons at a time are in ribosome
3
which codons are being read
codons in P and A
what do the letters E P and A stand for sites
E exit
A add on
P where it starts
what does tRNA do
bring amino acids to the ribosome Match the correct amino acid in place by matching their anti-codon to the mRNA codon Fit into the E, P and A sites
how many amino acid types do each tRNA pick up
ONLY ONE KIND
what does tRNA do after dropping off amino acids at ribosome
moves back into the cytoplasm to pick up another amino acid(but always the same kind)
what enzyme binds amino acids to tRNA
aminoacyl-tRNA synthetase
steps to translation
initiation
elongation
termination
translation initiation
Ribosome subunits bond to mRNA
tRNA that matches start codon binds at site P
translation elongation
tRNA that matches 2nd codon binds at site A
ribosome attaches the 2 amino acids those tRNAs carry to each other by a peptide bond
Ribosome moves down mRNA chain by one codon
the first tRNA
Moves into the E
site and exits
the ribosome
the next tRNA moves into place