Physiological Determinants of Global Health

Classroom Activities

Activity One: Strawberry Lab and DNA Puzzle

Essential Question: What about our cells make me different than you?

The introduction to the unit will be a hands-on activity to help gain momentum with student motivation and engagement. The purpose of the first activity is to provide students with a common experience that will help them when they need to work cooperatively in subsequent parts of the unit.

To prepare for the DNA extraction activity, students will view a short video on cells. The video will be a very basic introduction to the cell as the basic unit of life. A diagram of a cell will be given to students and very general overview of organelles will be discussed. The main focus will be on the structure and function of the nucleus.

The Strawberry DNA extraction activity requires students to follow a procedure to chemically breakdown and separate the DNA molecules in a frozen strawberry. Students are given frozen strawberries, baggies, and salt, water, and dish detergent. The contents are mashed together and eventually strained through a coffee filter. One strained, rubbing alcohol is added to the mixture and the DNA will “settle out” on top. Students can use a fork or a bamboo stick to pull the DNA out in globs.

I am choosing not to do this as an inquiry based activity, since my students would not have enough background knowledge to make hypothesis and create a procedure, however, students with a strong background in chemistry or biology could be challenged by being given a bin of materials and asked to come up with a procedure. I will link the DNA extraction activity to the scientific method by bringing up a discussion on controlled variables, sample size, and data collection. My students have sufficient background to discuss these topics, but other grade levels may need to modify as needed.

After students answer lab based questions about the DNA extraction, we will take guided Cornell Notes. As an AVID school (Advancement Via Individual Determination), we are required to model this type of note-taking and scaffold students into reflecting and asking questions about the notes. The notes will be basic information on DNA, genes, and chromosomes and how they relate to the nucleus. I will use distributed summarizing and focused note-taking strategies to help students begin to make connections. My goal for this activity is for students to work in pairs and be able to come up with at least one Depth of Knowledge (DOK) level three or four question. These questions require students to use strategic thinking to explain their understanding of concepts. DOK three or four questions may yield more than one answer and require a student to justify his or her reasoning.

Activity Two: DNA Puzzle and Small Group Reading

Essential Question: What makes a disease hereditary?

The hands on portion of the second activity reviews information about the cell and nucleus, but also previews the terms mutation and hereditary. To begin, students will view a short video on DNA. Then, they would work together in partners or groups of three to complete the DNA puzzle activity. The DNA puzzle pieces will be colored and students will create a key for showing what the colors represent (A, C, T, G, etc). After the puzzle is completed, I will refer back to the Cornell notes to discuss from where the pieces of the DNA originated (that is, we receive half from our mothers and half from our fathers). A graphic organizer, such as a frayer model, would be used to help me organize information from the class discussion. The graphic organizer would include sections for definitions, examples, non-examples, and a picture representation. I would like the class to come up with a definition of heredity on their own, but will be prepared to scaffold if necessary. This part of the lesson could be modified up to allow older students to work by themselves or in partners. It may be more appropriate to give younger students a definition.

On the smart board (or using magnetic pieces on the whiteboard), I would show a completed DNA molecule with one piece shaded black. This would help me introduce the idea of a mutation, or change, in DNA. While there are many ways these mutations can occur, sixth graders will only be responsible for understanding that an overall change has occurred.

Students would be given the reading “Genetics” from KidsHealth.Org and complete a close read of the text. The text paragraphs and lines would be pre-numbered to make it easier to students to reference information for the second part of the lesson. The first close read would be for them to code the text for new and important words. The second read would be for them to identify the main ideas of the text and use a highlighter to notate this. Finally, students would be responsible for creating text-dependent questions. An exit ticket would be used as a formative assessment to gather information on what students feel they strongly understand and in what areas they need additional support.

Activity Three

Essential Question: What happens when signals in a cell “get crossed” and don’t function properly?

The final activity will be a pair-share activity. Students will be assigned either CF or HSAN and will be responsible for reading articles relating to each disease. Using graphic organizers and note-taking strategies discussed earlier in the unit, students will become experts on the disease they have researched. The texts will include news articles as well as readings from kid-friendly health websites. After students have had some time to read and take notes on their own, I will ask them to share what they have learned. We will start our discussion of ideas by just generating information in list format. Then, students will sort and categorize the statements. They will need to give each category a heading and be prepared to explain their thoughts. For this activity, students will work by themselves initially, but will work in partners and then as groups of four to finalize the organization of the statements. The groups will put their final thoughts on poster paper and we will share out as a class to see common thoughts.