This is the introduction for the students to the parts that make up DNA. To start the teacher would give them a story telling them about Watson and Crick, Franklin, Wilkins, and Chargaff. Then tell them that they are going to be Watson and Crick working through the discovery of the structure of DNA. Give feeler questions that they should think about while working through it. How are you going to know which pieces fit together? Instructions: Students should be divided into groups of 2-4 students. Each group of students gets a bag that has 25 phosphate pieces, 25 ribose pieces, and 5 of each nucleotide. Students should work together to construct a correct model of DNA using the pieces they have been provided. Students should record their strand on a table they can keep for Part-II. Left Right Example of possible table provided. Post-Lab discussion: Students will do a whiteboard meeting with their different models. When students present their whiteboards they should all have answered a question the teacher has posed. Can bases pair with any base they want? Which of the base pairs match correctly? Then ask them if anyone has heard of another name we use for these base pairs? Do you think there is a reason one base-pair is larger than the other? (Leads teacher into introducing purines and pyrimidines). When introducing purines and pyrimidines can be general that pyrimidines have two pieces and purines have one and have them predict which bases fit into which category. Why do you think the assembled pairs are all the same length? Why do we always have three pieces for each pair? Do you notice anything that each base pair has? (Can lead them to the idea that there is a backbone by asking what do we have that holds us upright? Why do the two strands stay together? (After students deduce that something is holding them together the teacher can provide the name of the bond, hydrogen bonds.) Throughout the discussion the students should be able to come to the conclusion that Cytosine only pairs with Guanine and Thymine only pairs with Adenine. They should also have a firm understanding that DNA exists in a double strand.
This is the introduction for the students to the parts that make up DNA. To start the teacher would give them a story telling them about Watson and Crick, Franklin, Wilkins, and Chargaff. Then tell them that they are going to be Watson and Crick working through the discovery of the structure of DNA. Give feeler questions that they should think about while working through it. How are you going to know which pieces fit together? Instructions: Students should be divided into groups of 2-4 students. Each group of students gets a bag that has 25 phosphate pieces, 25 ribose pieces, and 5 of each nucleotide. Students should work together to construct a correct model of DNA using the pieces they have been provided. Students should record their strand on a table they can keep for Part-II. Left Right Example of possible table provided. Post-Lab discussion: Students will do a whiteboard meeting with their different models. When students present their whiteboards they should all have answered a question the teacher has posed. Can bases pair with any base they want? Which of the base pairs match correctly? Then ask them if anyone has heard of another name we use for these base pairs? Do you think there is a reason one base-pair is larger than the other? (Leads teacher into introducing purines and pyrimidines). When introducing purines and pyrimidines can be general that pyrimidines have two pieces and purines have one and have them predict which bases fit into which category. Why do you think the assembled pairs are all the same length? Why do we always have three pieces for each pair? Do you notice anything that each base pair has? (Can lead them to the idea that there is a backbone by asking what do we have that holds us upright? Why do the two strands stay together? (After students deduce that something is holding them together the teacher can provide the name of the bond, hydrogen bonds.) Throughout the discussion the students should be able to come to the conclusion that Cytosine only pairs with Guanine and Thymine only pairs with Adenine. They should also have a firm understanding that DNA exists in a double strand.
7-%20Overview%20for%20Cell%20Reproduction%20Model.docx