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  A nucleic acid backbone  single stranded.

III. Types of RNA Three types of RNA are used to make proteins  mRNA – messenger RNA  rRNA – ribosomal RNA  tRNA – transfer RNA

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

V. tRNA Function  To deliver amino acids to the ribosome as it is building (synthesizing) protein

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

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

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 three- letter “words” called codons

mRNA Codons  3 letters on mRNA 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 AUG = Start Codon This is where you begin translation of DNA’s code given to mRNA

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

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

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

–A tRNA delivers a Methionine (start codon), the first amino acid of each protein. –Many more tRNA’s deliver one of the twenty amino acids to match the codon of the mRNA to the anticodon of the tRNA. –The protein is synthesized (built) one codon at a time reading from 5’ to 3’ along the mRNA.  The protein only stops being built when a stop codon is read.

video  case/index2.html?id=586 case/index2.html?id=586 case/index2.html?id=586

A Gene = ?  Copy strand – strand being read  Original Strand – strand not being read A. Start Codon – AUG B. Stop Codon -  5’TerminationSTOPPoly A SequenceAUGPromoterOpen Reading Frame3’ C. Termination Sequence -