February 24, 2013

February 24, 2013

I hope everyone was able to enjoy their weekend.  I know ours was a busy one with lots of family time!

Events of the Past Week

Monday - No School.  Happy President's Day!

Tuesday - We began the Mendelian Genetics portion of our genetics unit on Tuesday.  The students were introduced to monohybrid crosses involving simple dominance and incomplete dominance, as well as a type of experiment called a testcross.  For homework, the students completed Problem Set 1.

Wednesday - Problem Set 1 was collected at the beginning of class.  We then spent a little time talking about some common human traits controlled by one pair of genes, such as having a widow's peak, a hitch-hiker's thumb, a longer second toe than big toe, or the ability to roll your tongue.  After investigating some of our own traits, we then learned how to perform a dihybrid cross.  The dihybrid cross is used to predict the outcome of a cross involving two different traits at the same time.  For homework, the students were given Problem Set 2.

Thursday - We learned about X-linked traits on Thursday.  Examples of common X-linked traits are red-green colorblindness, hemophilia, and Duchenne muscular dystrophy.  These are all traits whose genes are located on the X chromosome.  This means that males are more likely to have them because they only inherit one gene for any X-linked trait, meaning that a recessive gene cannot be hidden.  The students then worked on the first 8 problems for Problem Set 3, which were to be completed for homework.

Friday - The students began class by taking a prequiz assessment to see how ready they were for their quiz on Monday, which will cover monohybrid crosses, dihybrid crosses, simple dominance, incomplete dominance, X-linked traits, pedigrees, and testcrosses.  After the prequiz, the students were introduced to pedigrees, which are basically family trees.  After being introduced to pedigrees and how to interpret them, the students were given time to work on problems 9 and 10 from Problem Set 3, which are to be done for Monday.

Upcoming Events

Monday - The students will take their first genetics quiz, which will consist of 15 multiple choice problems and one, 3 part written problem.  After the quiz, the students will take a look at the pedigree for Queen Victoria's family to learn how an X-linked recessive trait caused the Russian Revolution and the rise of communism!  Afterwards we will listen to the song "I'm My Own Grandpa" by Ray Stevens and try to draw a pedigree of the family described in the song.  At the end of class I will take some time to explain the requirements of the lab report the students will be writing using the data from their fruit fly computer simulation that was run at the beginning of our unit.

Tuesday - We will learn about traits for which more than one allele exists in the population on Tuesday (such as blood types).  We will also learn about a type of inheritance called codominance (not to be confused with incomplete dominance) at the same time when we study blood types that day.  Homework will be to complete numbers 1-7 on Problem Set 4.

Wednesday - The students will be introduced to polygenic inheritance (traits controlled by more than one pair of genes, such as height and skin color).  For homework they will complete questions 9 and 10 in Problem Set 4.  Question 8 will be skipped as it covers a topic that we will learn about during our evolution unit.

Thursday - Problem Set 4 will be collected.  The students will then be introduced to the concept of epistasis, in which one pair of genes controls the expression of another set of genes.  We will look at coat color in labrador retrievers as our example.  For homework there will be worksheet with 2 different epistasis problems.

Friday - We will review everything we learned during the course of the week in preparation for our second genetics quiz on Monday.  If there is any time remaining after our review, the students can use that time to work on their fruit fly reports with their groups.  Homework will be to study for the quiz on Monday.

Graba Geek of the Week

This week's Geek of the Week goes to Madelyn Ziaj, who earned excellent grades on both Problem Set 1 and Problem Set 2, and was not afraid to send me questions via e-mail to help her when she was confused on anything in the homework.  Keep up the hard work, Madelyn!