Blog Archives - Mr. Powell Science

Genetics Exam Wrap Up and Ethics in Genetics Project

9/29/2017

Congratulations on completing your first 8th grade science exam! Grades are up in the grade book and if you feel compelled to retake any part of the test, see Mr.Powell about scheduling a retake. Additionally, if you still want to figure out the dihybrid cross. Here's a video on how to solve them.

Genetics Test Day!

9/28/2017

Genetics Exam Tomorrow!

9/27/2017

Tomorrow is your genetics exam. If you haven't completed your review packet, do that to study. I encourage you to look back through the last few weeks posts and watch some of the videos to prepare yourself for our exam tomorrow. If you didn't bring a review packet home, one is attached below. The answer key will be uploaded later tonight if you want to check your answers.

Genetics Review Packet.pdf
File Size:	77 kb
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genetics_review_answers_side_1.pdf
File Size:	385 kb
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genetics_review_answers_side_2.pdf
File Size:	378 kb
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genetics_review_answers_side_3.pdf
File Size:	328 kb
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genetics_review_answers_side_4.pdf
File Size:	333 kb
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Pedigree Quizzes returned and 100 Greatest Discoveries Genetics

9/26/2017

Students got back their graded Pedigree quizzes today, which we reviewed in class. Afterwards we watched most of a Discovery Channel production "100 Greatest Discoveries in Science: Hosted by Bill Nye" Students filled out a video guide sheet as we watched. Tomorrow Students will review for their exam with Mr. Houde.

greatest_discoveries_with_bill_nye.doc
File Size:	27 kb
File Type:	doc

Pedigree Quiz Today

9/25/2017

Students took a summative quiz on Pedigrees today. Our Genetics Unit Exam will be Thursday and will cover: DNA Structure and Function, Punnet Squares, and Pedigrees. If you are still struggling with Pedigrees, here is another helpful video that explains how to complete and interpret a pedigree.

...and even more pedigrees

9/22/2017

We continued our exploration of pedigrees today in preparation for our Pedigree quiz Monday. One of the more difficult pedigree problems is determining the "pattern of inheritance" exhibited in the pedigree. The video below gives a very thorough explanation of how you can tell what kind of inheritance is exhibited in any pedigree.

BONUS Gold Tape Question

Anyone can claim gold tape by completing the following task:
Make a pedigree of at least 4 generations based on a family from either a cartoon, movie, or book. You must identify what trait the pedigree traces, the genotypes and phenotypes of all members of the family, and pattern of inheritance. You may invent additional family members if needed but your pedigree must be based on an already established fictional family. Possible families you can use are The Simpsons, Family Guy, Flintsones or Jetsons, Harry Potter, Hobbits/Lord of the Rings, Hunger Games, and any other fictional family you like!

You have until the end of the school day Thursday September 28 to turn in your pedigree to Mr. Powell.

Gummi Bear Pedigrees

9/21/2017

Pedigrees are one of the more challenging concepts to wrap your head around in genetics. The basics of pedigrees, what the symbols and charts represent are easy, however interpreting and creating the pedigrees from a description can be quite the task. Today in class students tried their hand at pedigrees not just with pen and paper but with Swedish fish and gummi bears. The fish were "female" and the bears were "boys" and by reading about the family history, students were able to assemble pedigrees using their candy to represent the family members, with their color(s) representing their genotype.

More Pedigrees

9/20/2017

Today continued our exploration of pedigree charts. Depending on the type of trait, either Autosomal recessive or Autosomal Dominant, the Heterozygous individuals may be completely shaded in or only half shaded in. If the heterozygotes are completely shaded in, we can infer that the trait being traced in Autosomal Dominant, because the presence of a single dominant allele causes the trait to be expressed. However for Autosomal recessive disorders, the Heterozygotes are carriers of the recessive allele although they do not express the trait. We use half shaded symbols to show that the individual carries the affected allele despite not expressing the trait themselves.

Pedigree for an Autosomal recessive trait. Only homozygous recessive individuals express the trait. Heterozygotes are carriers and are depicted with a half shaded symbol.

Pedigree for an Autosomal Dominant trait. All carriers express the trait and therefore both homozygous dominant and heterozygous individuals are depicted with a completely shaded symbol.

Pedigrees

9/19/2017

Today's class focused on pedigrees. Pedigrees are tools we can use to look at the family history of certain traits. They are also very useful in visualizing the inheritance patterns of sex-linked traits. We will be spending the next few days learning to draw and interpret pedigree charts. The video below gives a very thorough explanation of how to use pedigrees to look at the inheritance of many different types of traits as well as their phenotypes and genotypes.

Sex Determination in Humans and other Animals

9/18/2017

In class today we reviewed the fruit fly lab from last week and discussed how it is possible that humans share 60% of the same DNA as fruit flies. Because all living things evolved from an original common ancestor, the genetics relationship between organisms can be described by how similar or different they are from each other. We talked about how humans are more closely related to dogs than to fruit flies but that we are even more closely related to chimpanzees than any other organism. In fact we share more than 98% of our DNA with chimpanzees, our closest living relative.

Additionally we discussed how the biological sex of an organism is determined and watched the video to the left which explained that sex determination is different among other groups of animals.