Introduction to Cells

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Objective

Students will be able to identify the structure and functions of various organelles located in a cell.

Big Idea

Cells are the basic building blocks of life.

Note to Teachers

This Introduction to Cells unit deals basically with organelle structure and function, and is part of of my Cells 'R Us project based learning experience. 

The Cells 'R Us project based learning experience is broken up into two units -- Cells and Organelles and Cell Processes. Instead of teaching all the content and then expecting the students to use it in their projects, I teach the content as the students progress through the project in an attempt to achieve "just-in-time" teaching. This allows me to chunk the lessons in a way that makes sense to the big project without overwhelming the students with information.

The complete sequence of lessons I use is:

In between that sequence, I provide work days so the students can integrate what they have learned into their final project. 

The specific lessons that cover the development of the project are:

Hook

5 minutes

To introduce the topic, I play Frank Gregorio's "Introduction to Cells".

I embedded the video into the webpage I developed for the project (Cells 'R US). The webpage also provides students with easy access to all the documents and resources they will need for the project.

I like using this video instead of the Inner Life of a Cell because the captions provide some direction for the discussions and activities that follow. 

Probe

15 minutes

Now that I have the students' attention, I distribute the atoms and cells probe, and give the students about 5 minutes to consider and write down their answers. I make it clear to the students that the probe is intended to explore what they think as they answer the why section, rather than just guessing the answer that they think I am expecting.

This means that in their answer to the "Why?" box, they must give specific reasons for their choice, and in the discussion that will follow we challenge their "why". I also tell students that defending their explanation is a specific skill that people with a scientific mindset need to develop (NGSS Practice 7), so I am expecting the use of complete sentences and academic language.

Once the students have written down their ideas, I ask them to pair up with an elbow partner to discuss their ideas before our class discussion. I tell that even if they came to the same conclusion, they must listen for the specifics in the explanations that they can add to, or challenge. 

I reconvene the class and discuss their answers and explanations. Since students have done it on their own, and then had an opportunity to practice their share (with possible challenges) with a partner, everyone in the whole class discussion can participate with minimal threat. 

Watch as the students discuss their ideas.

As we wrap up the probe discussion, we touch on "What makes a cell, a cell" eliciting however briefly the components of cell theory (All living things are composed of cells. Cells are the basic units of structure and function in living things. All cells come from existing cells.)

Note to teachers: In the probe you will notice I ask students to ACE their answers. ACE (Answer-Cite-Explain) is a strategy for demonstrating learning in short or extended response items. Follow the ACE link to learn more information as well as the prezi I use when I introduce the strategy.

Project Scenario

15 minutes

I display the Cells R Us scenario, and we read through it together once. I also have paper copies of the scenario and rubric that I distribute to table groups. 

I then write the driving question on the board:

How can I develop a model that explains what cells are, what they are made of and how they work?

Or alternatively, How can I, as a travel destination adviser, create a working analogy for the cell?

Their table task today is to develop their own list of "need to knows" based on the scenario, guiding question and rubric, as well as the skills that a team would need to have in order to perform successfully.

I give about 10 minutes for the students to work at their tables before we reconvene as a class to develop the class "need to knows", which I type on a document that will be shared with all students. In the past, I have done this on chart paper, but as my students now all have access to 1:1 computing, I think that this shared document might be useful as a readily accessible tool for all.

The need to know document is an integral part of a project based learning (PBL) experience. As the students begin their tasks they will be adding their answers, resources and new questions to the collective document, which will then serve as a powerful resource for all in their final projects.

Closure

10 minutes

In the previous section, the students also created a list of skills needed to do the research. I use chart paper to make a list of those identified skills. I tell the students that an important part of deciding who to work with is knowing that your team has most (if not all) of the skills present. 

In order to be able to make those good choices, I tell the students to go over the list, and identify the skills they think they posses. Then, before leaving the room, they must write their names next to "what they believe they bring to the project", so that when I/we create teams we have some balance. 

Usual questions that I hear:

Can I write my name more than once? Yes.

Can I not write my name at all? No, we all bring something to the table.

Does that mean that if I write my name as researcher, I have to do all the research? No (It just means that you might share some of the tricks you have learned that make you a "good researcher").

This system allows the students to take ownership of their participation in the project, as they become the go to person for that skill, and validates the participation of all.