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Why. How?. Lab 4: DNA – the instructions for life. First things first:. Why do we teach the way that we teach?. Modeling. Why we do it How to tell if we ’ re doing it right. What ’ s the difference. Between assertion and evidence ?
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Why How? Lab 4: DNA – the instructions for life
First things first: • Why do we teach the way that we teach?
Modeling • Why we do it • How to tell if we’re doing it right
What’s the difference... • Between assertion and evidence? • What constitutes a valid, coherent scientific argument that X is true? • Is the earth the center of the solar system? Justify!
Sense-making created by Piotr Kaczmarek http://dd.dynamicdiagrams.com/wp-content/uploads/2011/01/orrery_2006.swf
Is today ‘science’?Are these ‘investigations’? • The goal of science is to create simplifying worldview that is predictive and explanatory. • You’ll never feel the pull of electronegativity, the ‘pH-ey’ presence of a proton. But thinking in this way helps you explain, predict? • That’s what we’re going for today in this way of looking at the bases
Why use analogies? (181 only) • http://www.technologystudent.com/struct1/arch1.htm
Where we’ve been • Proteins and how they get their shape • Hemoglobin – explored one awesome protein in detail
Where we’re going • HOW does the cell know how to make Hemoglobin (and every other protein)? • Where are the instructions? • How are these instructions ‘read’? • Who does the building? • How can it be that none of the builders can ‘think’, ‘read’ or ‘understand’?
DNA! • Is the instruction molecule of the cell • Proteins are the action molecules of the cell • DNA contains the instructions for building proteins
Atoms: They’re how life works • DNA, RNA: C, H, N, O, P, [Mg++] • Carbs: C, H, O • Protein: C, H, N, O, (S), (P) How can this small assortment of atoms be used to both build the machines of the cell (proteins) AND store the instructions for the machines (DNA)?
Primary goals • Consider the necessary properties of a chemical that ‘is’ instructions • Understand DNA stores and relays the instructions • Understand HOW the bases go together • See that pairing is replication (storing) and transcription (relaying)
How to make sense of DNA? • Recipe book analogy
Now it’s your turn! • Have students do the Info-flow exercise
Once you have finished Information Flow, come up and get a worksheet. • The worksheet is a series of questions concerning how the analogy relates to the processes of replication and transcription/translation, so it will be beneficial to pay attention to what is written in the exercise as you do it • It will be worth points on your quiz next week
How does the recipe analogy make us smarter? • The whole recipe book = ?
How does the recipe analogy make us smarter? • The whole recipe book = ? • all the DNA in a cell (the whole genome)
How does the recipe analogy make us smarter? • The whole recipe book = ? • all the DNA in a cell (the whole genome) • What does a recipe represent?
How does the recipe analogy make us smarter? • The whole recipe book = ? • all the DNA in a cell (the whole genome) • What does a recipe represent? • Gene = section of DNA = instructions for making a protein
How does the recipe analogy make us smarter? • The whole recipe book = ? • all the DNA in a cell (the whole genome) • What does a recipe represent? • Gene = section of DNA = instructions for making a protein • The recipes for how many different dishes are in the book?
How does the recipe analogy make us smarter? • The whole recipe book = ? • all the DNA in a cell (the whole genome) • What does a recipe represent? • Gene = section of DNA = instructions for making a protein • The recipes for how many different dishes are in the book? • How many different types of genes are in the genome (all the DNA in a cell)?
How does the recipe analogy make us smarter? • The process of making a copy of the whole recipe book = ?
How does the recipe analogy make us smarter? • The process of making a copy of the whole recipe book = ? • The process of REPLICATION
How does the recipe analogy make us smarter? • The process of making a copy of the whole recipe book = ? • The process of REPLICATION • How much of the book would you want a copy of?
How does the recipe analogy make us smarter? • The process of making a copy of the whole recipe book = ? • The process of REPLICATION • How much of the book would you want a copy of? • How much of the DNA would a new cell want a copy of?
How does the recipe analogy make us smarter? • The copy of the recipe book that was given to you = ?
How does the recipe analogy make us smarter? • The copy of the recipe book that was given to you = ? • the copy of all the DNA that a new cell gets when it is made
How does the recipe analogy make us smarter? • The copy of the recipe book that was given to you = ? • the copy of all the DNA that a new cell gets when it is made • Things to think about: • If you had just been given the recipe book, would you make EVERY recipe in the book?
How does the recipe analogy make us smarter? • The copy of the recipe book that was given to you = ? • the copy of all the DNA that a new cell gets when it is made • Things to think about: • If you had just been given the recipe book, would you make EVERY recipe in the book? • Does a cell make all of the proteins that it has the instructions for?
How does the recipe analogy make us smarter? • The copy of the recipe book that was given to you = ? • the copy of all the DNA that a new cell gets when it is made • Things to think about: • If you had just been given the recipe book, would you make EVERY recipe in the book? • Does a cell make all of the proteins that it has the instructions for? • Put another way – does a ‘liver cell’ make all the proteins the DNA it contains has the instructions for?
How does the recipe analogy make us smarter? • Clarifications: • REPLICATION is just the very first part of the analogy (making a copy of the recipe book). • It is a separate process from everything else that follows
How does the recipe analogy make us smarter? • Process of making a photo copy of the recipe = • the processes of TRANSCRIPTION (making a copy of RNA from DNA) • Photo copy of the recipe =? • Strand of mRNA • How much of the recipe book should be taken to a picnic to make just one recipe? • How much of the DNA would need to be copied to make just one protein? • How permanent does the recipe copy need to be? • How permanent does the copy of the DNA (copy = mRNA) need to be?
How does the recipe analogy make us smarter? • Process of making a photo copy of the recipe =
How does the recipe analogy make us smarter? • Process of making a photo copy of the recipe = • the processes of TRANSCRIPTION (making a copy of RNA from DNA)
How does the recipe analogy make us smarter? • Process of making a photo copy of the recipe = • the processes of TRANSCRIPTION (making a copy of RNA from DNA) • Photo copy of the recipe =?
How does the recipe analogy make us smarter? • Process of making a photo copy of the recipe = • the processes of TRANSCRIPTION (making a copy of RNA from DNA) • Photo copy of the recipe =? • Strand of mRNA
How does the recipe analogy make us smarter? • Process of making a photo copy of the recipe = • the processes of TRANSCRIPTION (making a copy of RNA from DNA) • Photo copy of the recipe =? • Strand of mRNA • How much of the recipe book should be taken to a picnic to make just one recipe?
How does the recipe analogy make us smarter? • Process of making a photo copy of the recipe = • the processes of TRANSCRIPTION (making a copy of RNA from DNA) • Photo copy of the recipe =? • Strand of mRNA • How much of the recipe book should be taken to a picnic to make just one recipe? • How much of the DNA would need to be copied to make just one protein?
How does the recipe analogy make us smarter? • Process of making a photo copy of the recipe = • the processes of TRANSCRIPTION (making a copy of RNA from DNA) • Photo copy of the recipe =? • Strand of mRNA • How much of the recipe book should be taken to a picnic to make just one recipe? • How much of the DNA would need to be copied to make just one protein? • How permanent does the recipe copy need to be?
How does the recipe analogy make us smarter? • Process of making a photo copy of the recipe = • the processes of TRANSCRIPTION (making a copy of RNA from DNA) • Photo copy of the recipe =? • Strand of mRNA • How much of the recipe book should be taken to a picnic to make just one recipe? • How much of the DNA would need to be copied to make just one protein? • How permanent does the recipe copy need to be? • How permanent does the copy of the DNA (copy = mRNA) need to be?
How does the recipe analogy make us smarter? • Following the instructions on the copy of the recipe =
How does the recipe analogy make us smarter? • Following the instructions on the copy of the recipe = • Translation
How does the recipe analogy make us smarter? • Following the instructions on the copy of the recipe = • Translation • How many sandwiches could be made from the photo copy of the recipe at the picnic?
How does the recipe analogy make us smarter? • Following the instructions on the copy of the recipe = • Translation • How many sandwiches could be made from the photo copy of the recipe at the picnic? • How many proteins can be made from the mRNA?
How does the recipe analogy make us smarter? • Turkey club sandwich =
How does the recipe analogy make us smarter? • Turkey club sandwich = • a specific protein
How does the recipe analogy make us smarter? • Turkey club sandwich = • a specific protein • Every different dish in the recipe book =?
How does the recipe analogy make us smarter? • Turkey club sandwich = • a specific protein • Every different dish in the recipe book =? • all the different types of proteins
How does the recipe analogy make us smarter? • Turkey club sandwich = • a specific protein • Every different dish in the recipe book =? • all the different types of proteins • **Remember: A genome (all the DNA in a cell) stores the information needed to make every different protein • **However, only a small subset of proteins is ever made by a specific type of cell
Important point to remember: • REPLICATION is a completely separate process from TRANSCRIPTION/TRANSLATION • Transcription DOES not directly follow Replication • REPLICATION is the copying of the entire genome (ALL the DNA) in order to provide a new cell with a copy • TRANSCRIPTION is the copying of a section of DNA (gene) to make mRNA (a temporary messenger molecule) • TRANSLATION is the ‘reading’ of the mRNA in order to build a protein