Protein Synthesis DNA Replication Before a cell divides

Protein Synthesis

DNA Replication Before a cell divides, all the DNA must be copied During Interphase of the Cell Cycle, the DNA replicates or makes a copy of itself DNA Replication will produce 2 IDENTICAL new complementary strands following the rules of base pairing: A-T, G-C

Practice – DNA Replication GTACCTAGGCTAAACTGA ________________ TTAGCATACGGGTCAGA _________________

Protein Synthesis Cell DNA Transcription Translation m. RNA Ribosome Protein (chain of Amino acids)

DNA and Protein Synthesis • DNA contains the genetic information or genes to make proteins • Proteins are chains of amino acids linked together • These proteins determine the physical traits of an organism and control cellular functions.

What is a Gene? • A gene is a certain length or piece of DNA on a chromosome • A gene is made of 2 parts: 1. Exon – the expressed parts of the DNA sequence or part that is used to make a protein 2. Intron – the intervening, not expressed or used • Parts are cut, put together and then used to make RNA and proteins

How to make a Protein… • Step 1: Use DNA to make a messenger RNA molecule - Transcription • Step 2: Decode that messenger RNA to see which amino acids are needed to make a protein – Translation Flow of Information: DNA RNA Proteins

Protein Synthesis Step 1: Transcription 1. 2. DNA unzips Messenger RNA (or m. RNA) is made from DNA using base pairs Ø RNA is different from DNA: a) RNA is single stranded, not double stranded b) Instead of deoxyribose, it has ribose c) instead of Thymine, it uses Uracil (and U A) 3) m. RNA carries the genetic code from the nucleus to the ribosome in the cytoplasm

Protein Synthesis: Transcription

Eukaryotic Transcription Nuclear pores Cytoplasm DNA Transcription RNA Processing m. RNA G G AAAAAA Nucleus Export AAAAAA

Practice – Transcription DNA- G T A C C T A G G C T A A A C T G A m. RNA _______________ DNA - T T A G C A T A C G G G T C A G A m. RNA ________________

Codons Ø Codon: Codon is a group of three bases that code for a specific amino acid ex: AAA = Lysine Ø The codons code for 20 amino acids o Just like the alphabet has 26 letters to make all the words we know, the 20 amino acids make all the different proteins found in living organisms Ø The codons are the template for protein synthesis, which takes place on the ribosomes (r. RNA) in the cytoplasm

Protein Synthesis: Translation: 1. In the cytoplasm, m. RNA attaches to the r. RNA (ribosomal RNA) and starts reading the codons 2. t. RNA (transfer RNA) – carries amino acids to the ribosome and attaches them together to make a growing protein chain 3. When protein production is complete, the ribosome releases the protein chain, and the protein folds into a 3 D shape – the shape of the protein dictates is job or where it is used

DNA and Protein Synthesis – Codons and amino acids Name the Amino Acid: UAU Tyrosine CCG Proline AGU Serine GCA Alanine

Protein Synthesis: Translation

Translation - Initiation f. Met Large subunit E P A UAC 5’GAG. . . CU-AUG--UUC--CUU--AGU--GGU--AGA--GCU--GUA--UGA-AT GCA. . . TAAAAAA Small m. RNA subunit 3’

Translation - Elongation Polypeptide Arg Met Phe Leu Ser Aminoacyl t. RNA Gly Ribosome E P A UCU CCA 5’GAG. . . CU-AUG--UUC--CUU--AGU--GGU--AGA--GCU--GUA--UGA-AT GCA. . . TAAAAAA m. RNA 3’

Translation - Elongation Polypeptide Met Phe Leu Ser Gly Arg Aminoacyl t. RNA Ribosome E P A CCA UCU 5’GAG. . . CU-AUG--UUC--CUU--AGU--GGU--AGA--GCU--GUA--UGA-AT GCA. . . TAAAAAA m. RNA 3’

Translation - Elongation Polypeptide Met Phe Leu Ser Gly Arg Ribosome E P A CCA UCU 5’GAG. . . CU-AUG--UUC--CUU--AGU--GGU--AGA--GCU--GUA--UGA-AT GCA. . . TAAAAAA m. RNA 3’

Translation - Elongation Polypeptide Met Phe Leu Ala Ser Gly Aminoacyl t. RNA Arg Ribosome E P A CGA CCA UCU 5’GAG. . . CU-AUG--UUC--CUU--AGU--GGU--AGA--GCU--GUA--UGA-AT GCA. . . TAAAAAA m. RNA 3’

Translation - Elongation Polypeptide Met Phe Leu Ser Gly Arg CA C Ribosome E Ala P A UCU CGA 5’GAG. . . CU-AUG--UUC--CUU--AGU--GGU--AGA--GCU--GUA--UGA-AT GCA. . . TAAAAAA m. RNA 3’