Protein Synthesis Translation

Genes and Proteins The coded information in DNA is put to work through production of proteins. DNA > RNA > Protein > Trait (Melanin)

Genes and Proteins Some proteins: Muscle, skin, pigment, hair etc. Enzymes Help digest food Control Cellular Respiration - (break down glucose) Make spindle apparatus Enzymes control all the chemical reactions of an organism. By encoding the instructions for making proteins, DNA controls cells.

Proteins are polymers of amino acids. (Human Insulin) Genes and Proteins Proteins are polymers of amino acids. The sequence of nucleotides in each gene contains information for assembling the string of amino acids that make up a single protein.

RNA Differs from DNA: DNA double stranded: RNA single DNA deoxyribose sugar; RNA ribose DNA Thymine: RNA Uracil Uracil Hydrogen bonds Adenine

Computer Analogy Building Analogy DNA = CD for Game Protein Synthesis Computer Analogy DNA = CD for Game RNA = Computer and Monitor Protein = Game Building Analogy DNA = Printed Instructions RNA = Workers Protein = Product

Three Types of RNA: Messenger RNA (mRNA), brings instructions from DNA in the nucleus (headquarters) to the cytoplasm (factory). In the factory mRNA moves to the assembly line, a ribosome.

Three Types of RNA: The ribosome (assembly line), made of ribosomal RNA (rRNA) Binds to the mRNA Uses the instructions to assemble the amino acids in the correct order. Amino Acid rRNA mRNA

Three Types of RNA: Transfer RNA (tRNA) is the supplier. Delivers amino acids (raw materials) to the ribosome to be assembled into a protein. Amino Acid Ribosome tRNA mRNA

Translation: From mRNA to Protein “A communication in a second language having the same meaning as the communication in a first language” Converting a sequence of nitrogenous bases in mRNA into a sequence of amino acids.

Translation At ribosomes. Attaches to mRNA like a clothespin clamped onto a clothesline.

Translation Click image to view movie

Chain of RNA nucleotides Translation Amino acid Amino acids brought to ribosomes by transfer RNA. tRNA molecule attaches to only one type of amino acid. Chain of RNA nucleotides Transfer RNA molecule Anticondon

Translation A ribosome attaches to start of mRNA. tRNA, carrying a specific amino acid, approaches. tRNA anticodon pairs with mRNA codon. Ribosome mRNA codon

Translation First codon AUG codes methionine. Signals “start” Ribosome slides to next codon. Methionine tRNA anticodon

Translation New tRNA carries an amino acid to pair with second mRNA codon. Alanine

Translation Amino acids joined by peptide bond. Continues for 50 to thousands of amino acids to make a protein. Methionine Alanine Peptide bond

The Genetic Code The Messenger RNA Genetic Code Second Letter U C A G First Letter Third Letter Second Letter U C A G U Phenylalanine (UUU) Serine (UCU) Tyrosine (UAU) Cysteine (UGU) U Phenylalanine (UUC) Serine (UCC) Tyrosine (UAC) Cysteine (UGC) C Leucine (UUA) Serine (UCA) Stop (UAA) Stop (UGA) A Leucine (UUG) Serine (UCG) Stop (UAG) Tryptophan (UGG) G C Leucine (CUU) Proline (CCU) Histadine (CAU) Arginine (CGU) U Leucine (CUC) Proline (CCC) Histadine (CAC) Arginine (CGC) C Leucine (CUA) Proline (CCA) Glutamine (CAA) Arginine (CGA) A Leucine (CUG) Proline (CCG) Glutamine (CAG) Arginine (CGG) G A Isoleucine (AUU) Threonine (ACU) Asparagine (AAU) Serine (AGU) U Isoleucine (AUC) Threonine (ACC) Asparagine (AAC) Serine (AGC) C Isoleucine (AUA) Threonine (ACA) Lysine (AAA) Arginine (AGA) A Methionine;Start (AUG) Threonine (ACG) Lysine (AAG) Arginine (AGG) G G Valine (GUU) Alanine (GCU) Aspartate (GAU) Glycine (GGU) U Valine (GUC) Alanine (GCC) Aspartate (GAC) Glycine (GGC) Glycine (GGC) C Valine (GUA) Alanine (GCA) Glutamate (GAA) Glycine (GGA) A Valine (GUG) Alanine (GCG) Glutamate (GAG) Glycine (GGG) G

Translation Click image to view movie

mRNA re-use mRNA can be used again, not “used up” after just one. Can use the same plans to build many houses.

Codons DNA code is a series of 4 nucleotides, A, T, C and G. Each three nucleotides in a row on a gene code for a certain amino acid in that part of the protein. TGG-CGC-TAC Thr-Ala-Met Threonine, Alanine, Methionine

Summary Diagram