10 4 Proteins n The job of DNA

10. 4

Proteins n The job of DNA is to provide the instructions for making protein

Proteins n Proteins do the daily business of living, giving cells their shapes and unique abilities v. Movers, enzymes, supporters, defenders n Life’s diversity results from differences in kinds and arrangements of protein molecules

Proteins n What is a protein? v. Long chain of amino acids hooked together v. Only 20 amino acids exist, but they can be combined countless ways

Proteins & Genes n Genes have the instructions for what amino acids to link together and in what order they should be linked n 1 gene has the directions for 1 protein n DNA molecules are just genes after genes (directions for proteins, after proteins…

What determines the order of amino acids? n THE GENETIC CODE! n The genetic code consists of only 4 letters! Can anyone guess what they are? v A, T, G and C

What determines the order of amino acids? n The order of nucleotides/nitrogen bases determines what amino acids are used to make a protein n Codon—set of three nitrogen bases in a row that code for an amino acid

T G A A C T G T T A n How many codons are present? 4 n How many amino acids will be made? 4

Protein Synthesis n Has two parts 1. 2. Transcript ion Translation

Transcription n Creating a copy of m. RNA from DNA v DNA does not turn into m. RNA n DNA must stay in the nucleus where it is protected and can be repaired n m. RNA will leave the nucleus, and go the ribosome where the protein will be made v The m. RNA copy is COMPLEMENTARY not identical to DNA –http: //www. youtube. com/watch? v=Wsof. H 466 lqk

Differences between DNA & RNA Sugar Phosphate group Nitrogen bases Strands DNA RNA Deoxyribose Ribose Same ACGT ACGU Two One

Practice transcription E. G C T A T C A A T C G G C G A U A G U U A G C C F. T T A A T A C G T T C G G A A U U A U G C A A G C C G. C C A C G T G C A T G G U G C A C G U A H. A G C T T A G C C A T U C G A A U C G G U A DNA m. RNA

Translation n Actual protein construction, m. RNA provides the instructions to join amino acids together n Transfer RNA (t. RNA) with the help of ribosomal RNA (r. RNA) reads the m. RNA n Occurs at the ribosome n Anticodon—set of three nitrogen bases on t. RNA that match a codon on m. RNA

n http: //www. youtube. com/watch? v=5 b. L EDd-PSTQ n http: //flash. uww. edu/projectgallery/trn atranslation/index. html n http: //pubs. acs. org/cen/coverstory/85/8 508 cover. html

DNA TTT ACC TAC m. RNA AAA UGG AUG lys trp met

Practice Translation E. G C T A T C A A T C G G Transcription CGAUAGUUAGCC Translation arg----stop F. TTAATACGTTCGG AAUUAUGCAAGCC asp-----tyr-----ala-----ser---- Protein

Practice Translation G. C C A C G T G C A T GGUGCACGUA gly------ala-----arg----H. A G C T T A G C C A T UCGAAUCGGUA ser------asp-----arg-----

Practice Transcription & Translation n http: //learn. genetics. utah. edu/units/basi cs/transcribe/

• http: //www. wisconline. com/objects/index_tj. asp? obj. ID=AP 1302 – Protein synthesis • http: //www. youtube. com/watch? v=NJxobgk. PEAo – Nice overview • http: //www. lewport. wnyric. org/JWANAMAKER/ani mations/Protein%20 Synthesis%20 -%20 long. html – Lew ports biology place—good general overview of protein synthesis

• http: //www. youtube. com/watch? v=y. Z_IPafi o. SU – Newton • http: //www. youtube. com/watch? v=Ml 0 Oq. A Uz. EXU – Complicated RNA shows good proteins building at ribosome