Sunday, December 2, 2012

Cell Unit Study - Week 7 - RNA and Ribosomes

Week 7: We made mRNA, tRNA, ribosomes and proteins.

Ribosomes are factories inside the cells in our bodies which produce proteins. mRNA and tRNA are the instructions which tell the factories how each protein is made. We built a model of these factories along with the instructions by following the information in chapter 1 in The Way We Work by David Macaulay. Please note this is not an activity book, but a book which explains cells well. I developed this activity to compliment the book.

To build the ribosome, or factory, we used two toilet paper rolls, a cylindrical container and a cardboard box. Holes were cut in each end of the box and on both sides of the cylindrical container.


DNA contains instructions for creating proteins which are used in all parts of our bodies. DNA is so important that it always remains in the nucleus. Our DNA was represented by two strands of multicolored yarn. With our yarn (the molecules) purple always matches with red, orange with blue and pink with green.
mRNA is a copy of a small portion of DNA. Since purple molecules always match with red molecules, orange molecules with blue molecules and pink molecules with green molecules, only one strand of the DNA is copied into mRNA.

The mRNA is fed into the bottom of the ribosome.

The molecule on the mRNA is read by the ribosome and a corresponding tRNA with an attached amino acid is fed into the toilet paper roll in the ribosome.

The amino acids are represented by fiber.

This picture shows the inputs. mRNA on the bottom, and three corresponding tRNA with attached amino acids.
This picture shows the outputs. mRNA on the bottom which can be reused in another ribosome, tRNA on the left and a protein formed by combining amino acids.

tRNA comes out the toilet paper roll while the newly formed protein comes out the center container.



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3 comments:

  1. I love that you used wool roving!

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  2. Wow, this is quite complicated concepts that you have simplified by this ingenious activity. Mccaulay's book must be very inspiring to you. Did you think the kids were understanding it all?

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    1. I think they understood a great deal while we did the experiment which was actually several weeks ago. Now I would be happy if they remembered that a Ribosome has something to do with RNA, is like a little factory, and that DNA and RNA are related. Either way, if they do decided to study higher level sciences in the future the words will not seem quite so foreign.

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