Protein Synthesis How DNA uses RNA and Ribosomes

Protein Synthesis How DNA uses RNA and Ribosomes to make proteins.

RNA Characteristics I. Bases a. Adenine b. Cytosine c. Guanine d. Uracil e. Sugar – a ribose rather than a deoxyribose f. Phosphate

II. Structure v A nucleic acid backbone v single stranded.

III. Types of RNA Three types of RNA are used to make proteins v m. RNA – messenger RNA v r. RNA – ribosomal RNA v t. RNA – transfer RNA

IV. m. RNA Function TRANSCRIPTON A. transcribe DNA code B. take code outside of nucleus to ribosome C. give instructions to ribosome on how to build protein

V. t. RNA Function u To deliver amino acids to the ribosome as it is building (synthesizing) protein

VI. r. RNA Function u are where translation of RNA to protein takes place u Ribosomes are made up of protein and ribosomal RNA (r. RNA)

VII. Genes q q Where do we find genes? (short arm and long arm of chromosome) Stretch of DNA Genes face either direction on a strand p q

VIII. The CODE!! A. James Watson and Francis Crick, with the help of Rosalind Franklin’s X-ray crystallography images unraveled the structure of DNA: B. The fact that bases paired led directly to a theory of how DNA codes for proteins. It took a few years to determine that the bases spell threeletter “words” called codons

m. RNA Codons u 3 letters on m. RNA are called codons. These three letter codes are used to determine which Amino Acid is to be placed on the protein. Ex: TAC AUG = Start Codon This is where you begin translation of DNA’s code given to m. RNA

m. RNA Syntehsis (Transcription) – A m. RNA is transcribed (built) using the DNA as a template. – The anti-sense strand is used as the template. u The resulting m. RNA looks exactly like the template strand of the DNA, with one important distinction each T is replace with a U.

See the m. RNA codon chart (Pink) u Write the codon for Proline here: u Glycine? u Which amino acid has the most codons? u Which amino acid has the fewest? u Start codon starts each protein u Three codons tell a ribosome to stop making a protein. List them here:

Protein Syntehsis Translation – m. RNA is TRANSCRIBED or produced from DNA in the nucleus. – m. RNA is shipped from nucleus to the cytoplasm. – A ribosome hooks to the m. RNA and “reads” to the first start codon. AUG Anticodon – 3 letters found to match the m. RNA’s codon.

–A t. RNA delivers a Methionine (start codon), the first amino acid of each protein. –Many more t. RNA’s deliver one of the twenty amino acids to match the codon of the m. RNA to the anticodon of the t. RNA. –The protein is synthesized (built) one codon at a time reading from 5’ to 3’ along the m. RNA. u The protein only stops being built when a stop codon is read.

video u http: //www. dnai. org/text/mediasho wcase/index 2. html? id=586

A Gene = ? u u Copy strand – strand being read Original Strand – strand not being read A. Start Codon – AUG B. Stop Codon - u 5’Termination. STOPPoly A Sequence. AUGPromoter. Open Reading Frame 3’ C. Termination Sequence -