Transcription: Making RNA to Get the Instructions of DNA into the Cytoplasm
What is Transcription? Transcription is the transfer of genetic information from DNA into messengerRNA (mRNA). It occurs in the nucleus of the cell.
DNA: Nucleus Bound DNA will not leave the protection of the nucleus mRNA makes a copy of the DNA code and brings this copy into the cell’s cytoplasm
RNA Ribonucleic Acid 1. Uses ribose sugar rather than deoxyribose 2. Single stranded 3. Bases A, C, G, and U (uracil, substitutes for thymine)
Transcription 1.Two DNA strands separate. Only one strand serves as the template for the new RNA molecule. 2.Free RNA nucleotides line up along the template A –U & C-G 3.RNA polymerase links the nucleotides to form the RNA molecule. Read the caption to the class. Which DNA strand was the template for making the mRNA strand? How do you know?
Editing the mRNA Strand RNA polymerase begins transcription at the site of a promoter. Promoters contain a specific base sequence signaling the start of transcription. Introns are portions of RNA that are cut out of the RNA strand and discarded. Exons are the remaining pieces that are spliced back together to form the final mRNA strand.
How Do DNA & RNA Compare? https://www.youtube.com/watch?v=Wdt39RLmE_s
Translation: mRNA → Amino Acids In mRNA, a row of three nitrogen bases forms a triplet called a codon. Codons are translated into amino acids. The number of amino acids and their arrangement code for specific instructions. Example: CCG is the codon for the amino acid glycine Assign individual students codons 1-7. Demonstrate how to use the Genetic Code to Translate into AA.
The Genetic Code
How Do the 3 Processes Compare? Replication Transcription Translation ↓ ↓ ↓ DNA mRNA Amino Acids Nucleus Nucleus Cytoplasm
What are the 3 Types of RNA?
What are the 3 Functions of RNA? mRNA - Messenger RNA: Encodes amino acid sequence of a polypeptide. tRNA - Transfer RNA: Brings amino acids to ribosomes during translation. rRNA - Ribosomal RNA: With ribosomal proteins, makes up the ribosomes, the organelle that translates the mRNA.
Translation mRNA leaves the nucleus and travels to rRNA in the cytoplasm. 1. Initiation- Translation begins at the start codon AUG (methionine). 2. Elongation- The tRNA anticodon uses complementary base pairing to bring the appropriate amino acid. Peptide bonds connect the amino acids. 3. Termination- Translation ends when a stop codon is reached.
Compare and contrast the structure of DNA and RNA. Explain the process of transcription. Describe the roles of each type of RNA. Explain the process of translation.