assemble the dna follow base pair rules blue—guanine red—cytosine purple—thymine ...
TRANSCRIPT
Replication
Assemble the DNA
Follow base pair rules
Blue—Guanine Red—Cytosine Purple—
Thymine Green--Adenine
Replication
Assemble the DNA
Follow base pair rules
Blue—Guanine Red—Cytosine Purple—
Thymine Green--Adenine
Flow of information DNA stores information--blueprint.
› Replication to copy the information exactly. DNA to RNA is transcription—job
instructions.› Transcription to make a working template.
RNA to protein is translation—produce final product.› Translation to produce proteins for the cells.
Types of RNA
messenger RNA (mRNA). A copy of the gene that is being expressed.
ribosomal RNA (rRNA). Four different RNA molecules that make up the structure of the ribosome.
transfer RNA (tRNA). Small RNA molecules that act as adapters between the codons of mRNA and amino acids.
mRNA—single strand
mRNA is a complementary single strand that is transcribed from one DNA strand of one gene.
Working instructions to build one protein
One gene one mRNA One mRNA one protein
Editing messenger RNA A gene includes both
coding segments called exons and non-coding segments called introns.
Only exons are read for codons to produce proteins.
Introns are cut out and exons are spliced.
Reading the mRNA
The nucleotides are read in triplets called codons.
Reading starts at AUG, the start codon. Read groups of three until a STOP
codon is reached. Each codon is specific for a single
amino acid. There may be multiple codons for an
amino acid.
Transfer RNA
tRNA is a folded single strand of RNA which is able to bind to an amino acid. tRNA binds to one and only
one amino acid. tRNA has a series of three
nucleotides that make an anti-codon that matches up with the codon on mRNA
Ribosomes
Ribosomal RNA (rRNA) is a single strand RNA that folds.
2-4 rRNA join to make a ribosome
Ribosomes are the site of translation, an assembly machine for proteins.
Protein Synthesis--Preparation
Preparation: transcription of a gene in the DNA to mRNA
mRNA exits nucleus to cytoplasm.
Initiation Stage Step 1: mRNA joins a ribosome. Step 2: Read AUG start codon Step 3: tRNA brings in attached
amino acids. tRNA matches its anti-codon to the mRNA codon.
Attach methionine
Termination--STOP The elongation of the protein continues
until a STOP codon is read by the rRNA. Separate protein from ribosome. Ribosomes, mRNA, tRNA can be
reused.
Review DNA—getting from data to structure
DNA is an information structure To make something the data needs to be
transcribed to a working template. Transcription is the process of copying
DNA to a messenger RNA, mRNA.› In the nucleus
Translation is the process of converting the data sequence in mRNA into amino acids linked together to make a protein.› In the cytoplasm