Protein synthesis The big picture The central dogma

Protein synthesis

The big picture The central dogma: DNA RNA Proteins • The synthesis of proteins occurs in two major steps: – Transcription • DNA gene is transcribed into m. RNA – Translation • m. RNA (carrying the protein message) is used to build the protein

Dna vs. Rna • DNA • RNA – – – – Double stranded A, T, C, G A: T and C: G Deoxyribose sugar in nucleotides Single stranded A, U, C, G A: U and C: G Ribose sugar in nucleotides – 3 types of RNA: • m. RNA(messenger) • r. RNA(ribosomal) • t. RNA(transfer)

Types of RNA • m. RNA (messenger) – Copies the DNA and carries it out of nucleus to ribosome • r. RNA (ribosomal) – Part of ribosomes, structures that make proteins • t. RNA (transfer) – Acts as the “taxi” to bring in amino acid required from code.

Step 1: transcription • Location: Nucleus • DNA gene is converted into m. RNA (messenger) by the enzyme RNA Polymerase

Step 2: Translation • Location: cytoplasm • Machinery: Ribosome (r. RNA), t. RNA • Ribosome attaches to m. RNA and reads the message 1 codon at a time – 1 codon = 1 amino acid • t. RNA deliver the proper amino acids to the ribsome http: //www. 712 designs. com/animations/flash/translat ion/M 1_L 3 -2_Translation. html

Put it all together

The genetic code • Codon = sequence of 3 RNA nucleotides • Each codon is the code for an amino acid Practice: AUG = methionine (start) UAC = tyrosine CGG = arginine UGA = stop codon

Let’s do some more practice!

Protein Synthesis Practice • What would be the correct amino acid sequence for the following DNA template? T A C G G A C A T T C T A T C

Check your work Turn it in!

Take some time to answer the following questions: • • What are amino acids? What are a chain of Amino Acids called? How many different Amino Acids are there? How do you determine what amino acids the gene is coding for • Codon vs. Anticodon • Start codon vs. stop codon

Mutations • Good or bad? Let’s try identifying the different types of mutations! • Let’s look at different types of mutations!