Transcription and Translation

GENES Portion of a chromosome that codes for a specific trait Includes both introns and exons The structure and function of the cell is determined by genes that are active (not all genes are active).

RNA Single stranded Made of nucleotides Contains Uracil instead of Thymine Has Ribose (sugar)

Types of RNA mRNA messenger RNA Makes RNA copy of DNA rRNA Ribosomal RNA Part of ribosome tRNA Transfer RNA Brings amino acids to ribosome

DNA vs. RNA RNA DNA Single stranded Double stranded Bases = A, U, C, G Sugar = Ribose Copies DNA, makes protein DNA Double stranded Bases = A, T, C, G Sugar = Deoxyribose Carries genetic code

Transcription A segment of DNA is copied to mRNA. Exon: Segment of a gene that codes for protein Intron: Segment of a gene that is not expressed http://www.dnalc.org/resources/3d/index.html

Steps of Transcription Gene (DNA) unwinds Transcription starts at a PROMOTER (where RNA polymerase will attach) 3. RNA POLYMERASE READS DNA, MAKES A MATCHING STRAND OF RNA.

4. RNA detaches from the DNA, introns are removed. 5. mRNA leaves the nucleus

Replication vs. Transcription Replication Transcription *Makes DNA *Makes RNA *2 strands made *1 strand made

Codon vs. Anticodon Codon = Sequence of 3 nucleotides on mRNA, codes for an amino acid Anticodon = sequence of 3 nucleotides on tRNA, is complementary to the codon Codon

Genetic Code 64 codons Code for 20 amino acids and 3 “stop” signals Start codon: AUG (methionine) 3 Stop codons The three “stop” codons are UAA, UAG, UGA

Translation Ribosomes attach to and “read” mRNA, make protein.

Steps of Translation 1. tRNA binds to the “start” codon. Ribosome: 2. attaches to mRNA 3. matches tRNA with mRNA codon. 4. removes amino acid from tRNA.

Steps of Translation (cont.) 5. A bond forms between amino acids. A polypeptide chain is formed. Process continues until a stop codon is reached. 6. Ribosome releases the polypeptide chain which will fold to form a protein.

Protein Shape The shape of the protein is determined by the sequence of amino acids. The shape of the protein determines its function. If the order of the codons is changed, the resulting protein is changed (may not be functional).

Transcription/Translation Videos Crash Course: https://www.youtube.com/watch?v=itsb2SqR-R0 Bozeman: https://www.youtube.com/watch?v=h3b9ArupXZg http://www.youtube.com/watch?feature=player_embedded&v=NJxobgkPEAo http://highered.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/sites/dl/free/0072437316/120077/micro06.swf::Protein%20Synthesis

Transcription/Translation Practice http://learn.genetics.utah.edu/content/begin/dna/transcribe/ http://www.classzone.com/cz/books/bio_07/get_chapter_group.htm?cin=3&rg=animated_biology&at=animated_biology&var=animated_biology