protein synthesis Flashcards
what is a gene
length of DNA that codes for a protein
what is the genome
complete set of genes in a cell
what is the proteome
full range of proteins a cell can produce
what are introns
non coding parts of DNA
what is mRNA and its structure
messenger RNA
linear strand, complementary to DNA
triplet of bases called a codon
what is tRNA and its structure
transfer RNA
single, folded strand
triplet of bases called an anti-codon
carries amino acid
what happens in transcription
- DNA helicase unwinds DNA strand by breaking hydrogen bonds between bases
- one strand acts as template
- free RNA nucleotides in nucleoplasm are attracted to exposed bases
- RNA polymerase joins adjacent nucleotides, forming phosphodiester bonds
- mRNA leaves nucleus
what is pre-mRNA
eukaryotic cells contain non-coding parts of DNA called introns that are removed and the exons (coding parts) are sliced before mRNA leaves the cell
what happens in translation
- mRNA attaches to ribosome
- tRNA has complementary base pairs to mRNA codon and carries a specific amino acid
- a peptide bond forms between adjacent amino acids
- tRNA molecules released and process continues until a stop codon is reached
- mRNA and ribosome dissociate
what are 4 feature of the nature of genetic code
triplet code: three nucleotide bases code for specific amino acid
non-overlapping: each base only part of one codon
degenerate: different codons can code for same amino acid
universal: all organisms use the same genetic code
