leq: how does rna help to make a protein?
DESCRIPTION
LEQ: How does RNA help to make a protein?. 10.6 to 10.9. The Central Dogma of Biology. The Central Dogma of Biology. Transcription – DNA making RNA Translation – RNA making Protein; (aka protein synthesis). The Central Dogma of Biology. - PowerPoint PPT PresentationTRANSCRIPT
LEQ: How does RNA help to make a protein?
10.6 to 10.9
The Central Dogma of Biology
The Central Dogma of Biology Transcription – DNA
making RNA
Translation – RNA making Protein; (aka protein synthesis)
The Central Dogma of Biology Archibald Garrod (1909) –
determined that genes dictate phenotype through enzymes
His ideas stem from his observations of an inherited disease – Alkaptonuria where affected individuals have a defective enzyme that does not break down two amino acids as aresult the produce Alkapton which makes their urine to turn black
The Central Dogma of Biology George Beadle and
Edward Tatum (1940’s) – American geneticists working with bread mold (Neuraspora crassa)
Strains of nutritional mutants helped them prove that specific enzymes were need to at specific steps in metabolic pathways
“One Gene/One Enzyme”
Transcription DNA making RNA Takes place in the
nucleus One main enzyme –
RNA Polymerase RNA is transcribed
in a 5’ to 3’ direction
Only ONE strand of DNA is transcribed at a time
DNA language is rewritten in the process of Transcription
Nucleic acid language is converted to the language of proteins in the process
of Translation
TRANSCRIPTION Initiation – DNA separates and ONE strand serves as a template for the RNA; RNA polymerase binds to the promotor region of DNA
TRANSCRIPTION
Elongation -RNA elongates as complementary RNA nucleotides match up with DNA
nucleotides are added in a 5’ to 3’ direction; U is substituted for T
As RNA polymerase moves forward, RNA releases from DNA; and DNA rewinds
TRANSCRIPTION Termination – RNA polymerase reaches the terminator sequence & releases the DNA and RNA; DNA rewinds; RNA is ready for the next step
Transcription Promoter – specific nucleotide sequence in
DNA, located @ the start of a gene; binding site for RNA polymerase; where transcription begins
Transcription region – segment of DNA that is made into RNA; the gene
Terminator – sequence of nucleotides in DNA that marks the end of a gene. It signals
Sense Strand – the strand of DNA that is transcribed into DNA
Nonsense Strand – the strand of DNA this in not transcribed
The Rosetta Stone of Life
Genetic Code Universal – shared by all organisms;
the set of rules giving the correspondence between nucleotide triplets (codons) and amino acids in proteins
Codes for Amino acids –› Building blocks of a proteins› 20 different amino acids› Coded for by groups of three nucleotide
bases - codons
Codons
Codons – groups of three consecutive nucletides in mRNA that specifies a particular amino acid or a polypeptide termination signal› AUG – start codon; indicates the starting point for
translation; also codes for methionine› Stop codons – don’t code for an amino acid
instead it signals the end of translation