Title of notes: Transcription and Translation p. 16 & 17

Title within the notes:Transcription

I can describe the process used in the creation of a protein. Learning target I can describe the process used in the creation of a protein. Today I am… Actively engaged in lecture of transcription and translation. So that I’ll be able to… understand how important protein synthesis is to life. I’ll know I’ve got it when… Complete all notes and homework.

Pathway to Making a Protein DNA mRNA tRNA (ribosomes) Protein

Protein Synthesis The production or synthesis of polypeptide chains (proteins) Two phases: Transcription & Translation mRNA must be processed before it leaves the nucleus of eukaryotic cells

DNA  RNA  Protein Eukaryotic Cell DNA Pre-mRNA mRNA Ribosome Protein Nuclear membrane Transcription RNA Processing Translation DNA Pre-mRNA mRNA Ribosome Protein Eukaryotic Cell

Transcription The process of copying the sequence of one strand of DNA, the template strand mRNA copies the template strand Requires the enzyme RNA Polymerase

Template Strand

Transcription During transcription, RNA polymerase binds to DNA and separates the DNA strands RNA Polymerase then uses one strand of DNA as a template to assemble nucleotides into RNA

Transcription Promoters are regions on DNA that show where RNA Polymerase must bind to begin the Transcription of RNA Called the TATA box Specific base sequences act as signals to stop Called the termination signal

RNA Polymerase

mRNA Processing After the DNA is transcribed into RNA, editing must be done to the nucleotide chain to make the RNA functional Introns, non-functional segments of DNA are snipped out of the chain

mRNA Editing Exons, segments of DNA that code for proteins, are then rejoined by the enzyme ligase A guanine triphosphate cap is added to the 5” end of the newly copied mRNA A poly A tail is added to the 3’ end of the RNA The newly processed mRNA can then leave the nucleus

Result of Transcription New Transcript Tail CAP

mRNA Transcript mRNA leaves the nucleus through its pores and goes to the ribosomes

Title within the notes:Translation

Translation Translation is the process of decoding the mRNA into a polypeptide chain Ribosomes read mRNA three bases or 1 codon at a time and construct the proteins

Transcription Translation Transcription occurs when DNA acts as a template for mRNA synthesis. Translation occurs when the sequence of the mRNA codons determines the sequence of amino acids in a protein. Translation

Ribosomes Made of a large and small subunit Composed of rRNA (40%) and proteins (60%) Have two sites for tRNA attachment --- P and A

Step 1 mRNA transcript start codon AUG attaches to the small ribosomal subunit The exposed codon attracts a complementary tRNA The tRNA (anticodon) pairs with the mRNA (codon).

Step 2 Peptide bonds join the amino acids Bond is broken between tRNA and its amino acid.

Step 3 The ribosome pulls the mRNA strand the length of one codon. The tRNA is then shifted into the exit site and released The next mRNA (codon) is exposed.

End Product –The Protein! The end products of protein synthesis is a primary structure of a protein A sequence of amino acid bonded together by peptide bonds aa1 aa2 aa3 aa4 aa5 aa200 aa199

Reading Transcription Pages 229 -232 Translation Pages 233 -237 Write down two facts from transcription and bullet point facts Write down two facts from translation and bullet point facts

3 steps of translation Create a foldable with the 3 steps of translation. Create a drawing for each step Short description of what occurs during the step