Protein Synthesis

DNA Transcription Ribosome mRNA Translation Protein (chain of Amino acids) Protein Synthesis Cell

DNA and Protein Synthesis • DNA contains the genetic information or genesto make proteins • Proteins are chains of amino acidslinked together • These proteins determine the physical traitsof an organism and control cellular functions.

What is a Gene? • A geneis 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, “junk DNA”, 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 RNAProteins

Protein Synthesis • Step 1: Transcription • DNA unzips • Messenger RNA (or mRNA) is made from DNA using base pairs • RNA is different from DNA: • RNA is single stranded, not double stranded • Instead of deoxyribose, it has ribose • instead of Thymine, it uses Uracil • 3) mRNA carries the genetic code from the nucleus to the ribosome in the cytoplasm

Protein Synthesis: Transcription

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

Codons • Codon: is a group of three bases that code for a specific amino acid • ex: AAA = Lysine • The codons code for 20 amino acids • 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 • The codons are the template for protein synthesis, • which takes place on the ribosomes (rRNA)in the • cytoplasm

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

Protein Synthesis: Translation • Translation: • In the cytoplasm, mRNA attaches to the rRNA(ribosomal RNA) and starts reading the codons • tRNA(transfer RNA) – carries amino acidsto the ribosome and attaches them together to make a growing protein chain • When protein production is complete, the ribosome releases the protein chain, and the protein folds into a 3D shape

Protein Synthesis: Translation

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

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

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

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

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

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

Protein Synthesis