protein synthesis Flashcards
what is transcription?
copying a gene into a complementary strand of mRNA
first step of transcription (point 1)
DNA helix unwinds, exposing the bases as DNA helicase breaks hydrogen bonds between complementary bases
how many strands act as a template for transcription? (Point 2)
Only one strand of DNA
what happens after strands separated? (Point 3)
Free RNA nucleotides line up opposite exposed complementary DNA bases
What happens after RNA nucleotides line up? (Point 4)
RNA polymerase joins RNA nucleotides into strand of pre-mRNA (phosphodiester bonds between adjacent nucleotides)
Continues until stop codon reached
What happens after strand of pre-mRNA is made? (Point 5)
Pre-mRNA is released and DNA rewinds
What happens after pre-mRNA is released? (Point 6)
Pre- mRNA is spliced, removing introns forming functional mRNA
What is translation?
Turning mRNA into a sequence of amino acids (primary structure)
What is the first step of translation? (Point 1)
mRNA attaches to ribosome in the cytoplasm, at the start codon
What happens after mRNA attaches to ribosome? (Point 2)
tRNA molecules with complementary anti-codon attaches to the first codon of mRNA
what happens after tRNA attaches to mRNA? (Point 3)
The ribosome moves along mRNA to enable another complementary tRNA to attach to the next codon on mRNA
What happens after another tRNA molecule attaches? (Point 4)
Two amino acids are joined by a peptide bond in which requires ATP
what happens after two amino acids bond together? (Point 5)
This continues until ribosome reaches stop codon at end of mRNA, amino acid chain detaches from ribosome
What happens once the amino acid chain detaches? (Point 6)
Polypeptide chain is sent to the Golgi to become folded and modified
