protein synthesis Flashcards
difference between eukaryotic DNA and prokaryotic DNA
E - linear P - circular
E - associated with histones P - not associated which histones
E - genes cotnain introns P - genes don’t contain introns
introns
non coding DNA base sequences within a gene
DNa is chloroplasts and mitochondria
like prokaryotic
mRNA structure
single stranded
Linear
complementary copy of a single gene to the template of DNA
length varies upon number of bases so it SHORTER than DNA
has codons
DNA vs mRNA
D - double stranded M - single stranded
D - longer M- shorter
D - thymine M - uracil
D - deoxyribose M - ribose
D - H bonds M - no H bonds
D - introns M (mature) - no introns
tRNA structure
single stranded
cloverleaf structure
anticodons
shorter than mRNA
tRNA function
carry a specific amino acid to the ribosome
genome
complete set of genes in a cell
proteome
full range of proteins that a cell is able to produce
loci
position of a gene within a chromosome
gene
a dna base sequence that codes for a sequence of amino acids in a polypeptide chain
transcription
DNA helicase unwinds DNA double helix, breaking H bonds between the 2 strands
the strands seperate, one acts as a template
complementary free RNA nucleotides are attracted to excposed DNA bases
RNA polymerase joins adjacent RNA nucleotides together forming phosphodiester bonds
mRNA formed is complimentary to the DNA and called pre mRNA
Introns are now removed by splicing to produce mature mRNA
exons are spliced back togetehr
mRN passes out of nucleus via nuclear pore to the ribosome
what are ribosomes amde up of
rRNA nad ribosomal proteins
translation
mRNA binds to a ribosome
tRNA carrying specfific amino acid occupies first binding site where start codon is located
ATP provides energy to bind amino acid to tRNA
second tRNA carryinga specfiic amino acid binds to the second binding site on mRNA codon (base pair)
ribosome catalyses the formation of peptide bonds between aminoa cids
ribsosome moves along mRNA to include the next codon
tRNA lost from first codon
process repeats until stop codon is reacged
polypeptide released ito the RER as the ribosomal complex falls apart
universal
the same 3 bases of DNA code for the same amino acid in all organisms
non overlapping
each base is only part of 1 triplet
degenerate
more than one triplet codes for one amino acid
