Cell Biology continuation

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During the first part of science class today, we talked about plant cells. I asked students to think about what structures studied so far (in animal plants) might be found in plant cells. They mentioned cell membrane, nucleus, nucleolus, rough endoplasmic reticulum, and smooth endoplasmic reticulum. I talked about the cell wall, vacuole, chloroplast, mitochondria, and plasmodesmata. We made a drawing of a plant cell with labels and descriptions. I then assigned their cell model homework (due next Monday, November 5^th). We have 3 students working on animal cell models, and 3 working on plant cell models. They will present their models on Monday. I gave them printed instructions for this project (will send parents an electronic version), and they are encouraged to use their drawings from class, and reliable Internet sources (feel free to ask me for references if you don’t know much about the subject) when working on this.

After the break, we talked about DNA – chromosomes, and structure of DNA. My goal was to provide basic, introductory information about transcription and translation so that we could play the “genetic Frankenstein game”. This game can be used for an active, interactive introduction to genes, transcription and translation. Kids are assigned a few physical traits, and asked to build a piece of DNA coding for the assigned traits (codes were provided to students on a handout that is in their science binder that should go home this week). At the end of the game, kids translate the sequences into a Frankenstein drawing. Unfortunately, we were running out of time, and I feel like most concepts weren’t clear. I will spend more time on this activity next week.

A quick note: we will eventually talk about evolution of life on Earth and have a discussion about cells from an evolutionary perspective.

Katrin had enough time to finish a piece of the DNA molecule for the genetic Frankenstein game.

Cell Biology

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This week my focus was on cells. We started by discussing functions of cells, and then started summarizing the structure of an animal cell. I was drawing on the board and having kids draw with me on a paper that will be kept in they science folder (I am not sure if all parents know, but each student has a science folder with all the work that they have been doing). We started with the cell membrane (lipid bilayer with proteins embedded), its functions (protection and regulation) and structure. We also talked about the nucleus; we talked about DNA and RNA (briefly, will talk more about their functions in the near future), the endoplasmic reticulum (rough and smooth), mitochondria, golgi apparatus, lysosome, vesicles, centrioles, and cytoskeleton.

The kids were really interested in the names and functions of the organelles. On Monday, Luke asked about the size of cells (why they can’t be huge), so on Wednesday we talked about diffusion (passive transport of molecules across membrane). We played a game outside – two kids were oxygen molecules, three were the plasma membrane, and two were mitochondria – we then had a discussion about the amount of energy required for diffusion in small vs. large cells. We ended the class with a you tube video (tour of the cell) and I gave the kids the link to a website that summarizes the structures and functions of cells. Next week I will assign a homework project; I will have each student build a model of a cell (plant or animal). They will have one week to work on this, and the link I provided could be helpful for this assignment. I will provide more information about this project next week.

At the very end of class, we talked about the restoration project. We are going to McLaughlin next Friday. Anybody is welcome to join us. We have about 60 seedlings to transplant.

The following standards were covered this week:

7^th grade Life Sciences

Cell Biology

1.      All living organisms are composed of cells, from just one to many trillions, whose details usually are visible only through a microscope. As a basis for understanding this concept:

a.       Students know cells function similarly in all living organisms. b.  Students know the characteristics that distinguish plant cells from animal cells,

including chloroplasts and cell walls.

c.       Students know the nucleus is the repository for genetic information.

d.      Students know that mitochondria liberate energy for the work that cells do.

Next week we will talk about plant cells, and if we have time I will start talking about cell division and differentiation. I will have a summary of the restoration project for kids to read in the car (it will take us a little over 2 hours to get to McLaughlin). 

Below are two pictures of the kids playing the diffusion game:

Becca, Julia, and Katrin were representing the cell membrane.

Garnet was an oxygem molecule looking for mitochondira.

New biology unit

            Last week we only had science class on Wednesday (I wasn't feeling good on Monday). We spent our time finishing the geology unit and checking on our seedlings for the restoration project. The kids had to finish a geology worksheet, finish their geological timeline, and start extra seeds on germination towels. We are going to McLaughlin on Friday, November 2nd, to plant seedlings at the restoration site.
          On Monday we started an unit about life, and cells. This unit will lead us to genetics. I started the class by asking students to discuss, in groups, what it means to be alive. I asked them to create a list of characteristics that can be used to classify things as living or nonliving. Both groups had common characteristics in their lists, including: movement, cells, evolution and energy. I showed them a few pictures and asked them whether they were looking at living or nonliving things. The class wasn't sure about the classification of seeds, fire and coral reef. We then discussed a few more characteristics of living things (respond to stimuli and have metabolism).
          After this discussion, we had our first "lab". I had a small microscope connected to my computer, and we used it to examine our skins, our clothes, sand, leaves, an ant, Vaca's hair and nose etc. We had fun! Chris took some pictures that I will be adding to this post (bottom).
          Today, Wednesday, we concluded our discussion about characteristics of living things and had a brief discussion about genes and evolution. It was a very interesting discussion - the kids were really involved and actively discussing their thoughts. One of the students asked me why some plants have thorns and I asked them why thorns would be an advantage for the plant. Katrin and Rodrigo talked about protection (of genes), and Garnet was really interested in knowing why/how new traits establish. I told them that mutations are random events, Luke pointed out survival of the fittest and we talked about adaptation.
          On Monday, a few students weren't convinced that seeds are living things so we dissected a bean today. I showed them the embryonic leaves and root. During the last few minutes of class, students looked, under a microscope, at single celled organisms that live in Putah creek.We saw algae and rotifers. Next week we will take a look at cheek cells, plant cells, and some more protists.

Yosemite's Biotic Zones project

 In the last two weeks, students have been learning about the 5 biotic zones found in Yosemite. They spent the first day summarizing their assigned zones and had two sessions to work on the models.

Becca and Garnet worked on the foothill-woodland zone and the lower montane forest. Josh, Luke, and Rodrigo worked on the upper montane forest and on the subalpine forest. Julia and Katrin were responsible for the alpine zone and fire ecology.

Yesterday, Wednesday Oct. 3, students presented their projects to the lower grades.

Here are some pictures of the final projects: