Transcription and Translation Protein Synthesis! Transcription and Translation

What you will learn today In Transcription, DNA is copied to make a strand of RNA. Transcription occurs in the nucleus. In Translation, proteins are made from RNA. Translation occurs in the ribosome. Codons are 3 nucleotides that code for an amino acid, which then make proteins. The Gene Scene: http://www.youtube.com/watch?v=xc2wbIDfO7E

Quick DNA Review DNA Structure video: http://www.youtube.com/watch?v=qy8dk5iS1f0&feature=player_embedded

DNA vs. RNA Full Name Sugar Structure Nitrogen Bases Deoxyribonucleic Acid Ribonucleic Acid Sugar Deoxyribose Ribose Structure Double Stranded Single Stranded Nitrogen Bases A, T, C, G A, U (Uracil), C, G

DNA vs. RNA Location Outside of the nucleus (ribosome) Nucleus Picture

Transcription and Translation DNARNAProtein

Central Dogma DNA has the instructions for the order of amino acids which determines the proteins that make up the traits (including physical characteristics such as height, eye color, hair color, etc.) of any organism.

Step 1: Transcription Function: A single strand of RNA is made from DNA. DNA RNA Location: Nucleus The DNA is kept safe in the nucleus while the RNA is sent out into the cell to direct the building of proteins http://www.concord.org/~btinker/workbench_web/models/eukTranscription.swf

Steps of Transcription RNA polymerase (an enzyme) attaches to DNA at a special sequence that serves as a “start signal”. The DNA strands are separated and one strand serves as a template. The RNA bases attach to the complementary DNA template, and mRNA is made!

Steps of Transcription The RNA polymerase recognizes a ‘stop’ part on the DNA molecule and releases the new mRNA molecule. (mRNA leaves the nucleus and travels to the ribosome in the cytoplasm.) http://www.stolaf.edu/people/giannini/flashanimat/molgenetics/transcription.swf

Think-Pair-Share DNA: AATCTAGATCATTA RNA:________________ Transcribe this strand of DNA into RNA (Transcription!): DNA: AATCTAGATCATTA RNA:________________ *Remember: There are no ‘T’s in RNA! Press play; ask S to make T-chart to remember differences between RNA and DNA; Press next when blinking or after students have shared some differences; add name of sugar to chart Press next; add different base to chart Press next; add number of strands to chart

Step 2: Translation Function: Pieces of RNA make amino acids, which then make proteins. RNA Proteins Location: Ribosome http://www.concord.org/~btinker/workbench_web/models/eukTranscription.swf

Types of RNA There are different types of RNA: mRNA: messenger RNA Carries a message (genetic code) from the nucleus to the ribosome (how to make proteins) tRNA: transfer RNA Transports amino acids to the ribosome Press play; ask S to make T-chart to remember differences between RNA and DNA; Press next when blinking or after students have shared some differences; add name of sugar to chart Press next; add different base to chart Press next; add number of strands to chart

Steps of Translation mRNA leaves the nucleus and binds to a ribosome. Press play; ask S to make T-chart to remember differences between RNA and DNA; Press next when blinking or after students have shared some differences; add name of sugar to chart Press next; add different base to chart Press next; add number of strands to chart

Steps of Translation The ribosome looks for codons. Codon: group of 3 nucleotides on the messenger RNA that specifies one amino acid. Press play; ask S to make T-chart to remember differences between RNA and DNA; Press next when blinking or after students have shared some differences; add name of sugar to chart Press next; add different base to chart Press next; add number of strands to chart

Steps of Translation tRNA (transfer RNA) carries Amino Acids to the mRNA. This tRNA has an anticodon that matches the codon on the mRNA strand. Anticodon: group of 3 unpaired nucleotides on a tRNA strand. Press play; ask S to make T-chart to remember differences between RNA and DNA; Press next when blinking or after students have shared some differences; add name of sugar to chart Press next; add different base to chart Press next; add number of strands to chart

Steps of Translation Each amino acid is dropped off and a chain forms. When the chain is completed, it disconnects and makes a protein! Press play; ask S to make T-chart to remember differences between RNA and DNA; Press next when blinking or after students have shared some differences; add name of sugar to chart Press next; add different base to chart Press next; add number of strands to chart Interactive animations : http://www-class.unl.edu/biochem/gp2/m_biology/animation/gene/gene_a3.html http://www.stolaf.edu/people/giannini/flashanimat/molgenetics/translation.swf

Use these charts for translation!

Let’s Practice!! The mRNA sequence reads the following codons. What amino acids do they stand for? AUG GGA GAG CAA What amino acid does the anticodon CGU stand for? Press play; ask S to make T-chart to remember differences between RNA and DNA; Press next when blinking or after students have shared some differences; add name of sugar to chart Press next; add different base to chart Press next; add number of strands to chart

Let’s Practice!! AUGCGACGAAUUUAA Find the amino acid sequence for the following mRNA sequence (translation): AUGCGACGAAUUUAA Press play; ask S to make T-chart to remember differences between RNA and DNA; Press next when blinking or after students have shared some differences; add name of sugar to chart Press next; add different base to chart Press next; add number of strands to chart

Think-Pair-Share DNA: AATCTAGATCATTAC RNA:________________ First-- Transcribe this strand of DNA into mRNA: DNA: AATCTAGATCATTAC RNA:________________ *Remember: There are no ‘T’s in RNA! Press play; ask S to make T-chart to remember differences between RNA and DNA; Press next when blinking or after students have shared some differences; add name of sugar to chart Press next; add different base to chart Press next; add number of strands to chart

DNA: AATCTAGATCATTAC RNA: UUAGAUCUAGUAAUG AA: ___ ___ ___ ___ ___ Second—Translate that strand of mRNA into amino acids. DNA: AATCTAGATCATTAC RNA: UUAGAUCUAGUAAUG AA: ___ ___ ___ ___ ___ Press play; ask S to make T-chart to remember differences between RNA and DNA; Press next when blinking or after students have shared some differences; add name of sugar to chart Press next; add different base to chart Press next; add number of strands to chart

DNA: AATCTAGATCATTAC RNA: UUAGAUCUAGUAAUG AA: Leu Asp Leu Val Met Second—Translate that strand of mRNA into amino acids. DNA: AATCTAGATCATTAC RNA: UUAGAUCUAGUAAUG AA: Leu Asp Leu Val Met Press play; ask S to make T-chart to remember differences between RNA and DNA; Press next when blinking or after students have shared some differences; add name of sugar to chart Press next; add different base to chart Press next; add number of strands to chart

Review Transcription Translation Proteins mRNA Ribosome Nucleus Amino Acids Ribosome