The focus of today's lesson was on gene expression. We began our discussion by discussing Garrod's study of alkaptonuria and how that led him to deduce that a gene error is responsible for an enzymatic malfunction (he hypothesized that genetic diseases are inborn errors of metabolism). Beadle and Tatum's work with neurospora supported Garrod's hypothesis by using mutant strains grown in minimal media. Here is a link to a great animation about this experiment: Dolan DNA Learning Center.
In the last 15 minutes of class students were given time to look over last week's test on DNA Replication and Meiosis. Test corrections will be due Monday, December 13th at 3:05.
There is a quiz on Chapter 17 planned for Friday, December 10th.
Monday, December 6, 2010
Friday, December 3, 2010
Introducing Gene Expression
We started class today by making holiday cards for Gary. Thank you to everyone who participated! I don't think we often appreciate how much our community means to Gary and how much he means to us. Hopefully our cards will bring him smile over the December break.
In all classes except third I gave you a pre-test on the concepts of gene expression. This did not count, but served as a gauge for how much students remember from their Biology class. Based on what you learned by taking the pre-test I asked students to look back over 17.1 and 17.2 to make sure you had a general understanding of how DNA is used to make protein.
Third period was able to begin a discussion of the one-gene-one-protein hypothesis by examining Beadle and Tatum's experiment with Neurospora. Other classes will begin this on Monday.
Have a great weekend! Good luck to football at State! And if you are in the school performance of Sight Unseen "break a leg!"
In all classes except third I gave you a pre-test on the concepts of gene expression. This did not count, but served as a gauge for how much students remember from their Biology class. Based on what you learned by taking the pre-test I asked students to look back over 17.1 and 17.2 to make sure you had a general understanding of how DNA is used to make protein.
Third period was able to begin a discussion of the one-gene-one-protein hypothesis by examining Beadle and Tatum's experiment with Neurospora. Other classes will begin this on Monday.
Have a great weekend! Good luck to football at State! And if you are in the school performance of Sight Unseen "break a leg!"
Thursday, December 2, 2010
Wrapping Up DNA Replication
To start class today I gave students a chance at some extra credit on Monday's test. Each student was given a set of 15 pictures to first separate into mitosis and meiosis and then put in order. See me as soon as possible if you were absent for this opportunity!
We finished our discussion of DNA replication by discussing how errors are minimized. This is addressed on p. 305 of your textbook. Next we talked about why the ends of chromosomes shorten with each replication. The process is summarized on p. 306. Our conversation extended to the ethical implications of using telomerase as a treatment for disease and/or aging. It is an interesting area to think about and one that we will likely be hearing more about in the next decade!
Toward the end of class I shared an AP Free Response question on the topic of DNA structure and replication. The question is below:
Scientists seeking to determine which molecule is responsible for the transmission of characteristics from one generation to the next knew that the molecule must (1) copy itself precisely, (2) be stable but able to be changed, and (3) be complex enough to determine the organism's phenotype.
We finished our discussion of DNA replication by discussing how errors are minimized. This is addressed on p. 305 of your textbook. Next we talked about why the ends of chromosomes shorten with each replication. The process is summarized on p. 306. Our conversation extended to the ethical implications of using telomerase as a treatment for disease and/or aging. It is an interesting area to think about and one that we will likely be hearing more about in the next decade!
Toward the end of class I shared an AP Free Response question on the topic of DNA structure and replication. The question is below:
Scientists seeking to determine which molecule is responsible for the transmission of characteristics from one generation to the next knew that the molecule must (1) copy itself precisely, (2) be stable but able to be changed, and (3) be complex enough to determine the organism's phenotype.
- Explain how DNA meets each of the three criteria stated above.
- Select one of the criteria and describe experimental evidence used to determine that DNA is the hereditary material.
Subscribe to:
Posts (Atom)