Are Sponge Bob's Genes Really Square?

This weekend, all of my little Geneticists will be busy completing the Bikini Bottom Genetics Take Home Test. Since the test is to be completed at home, I do expect for you to use your resources - your notebook, this blog, the internet, your textbook....whatever you need to do your best on the test. In this post, I will include reminders to several key concepts about Genetics, probability and Punnett Squares. Make sure that you read each question on the test carefully, check your work and do the best that you can!




Vocab to help you with the test (also found on your yellow vocabulary sheet):

• Allele - an alternate form of a gene. For our study of Genetics in 7th grade, we are only working with genes that have two alleles for each trait (humans are much more complex than this, though). Represented using letters (ex: H, h, B, b, T, t)



• Homozygous - genotype in which the two alleles in the pair are identical (ex: HH, hh). Also known as a purebred.



• Heterozygous - genotype in which the two alleles in the pair are different from one another (ex: Hh). Also known as a hybrid.



• Phenotype - the physical characteristic displayed by the trait (ex: brown hair, blue eyes). Can be observed.



• Genotype - the actual genetic makeup of the organism (allele pairs). Not always able to be observed. (ex: BB, Bb, bb)



• Dominant - form of the trait that is always expressed. Represented using uppercase letter (ex: H, B, T)



• Recessive - form of the trait that is only expressed when paired with another recessive allele. Can be masked by a dominant allele; represented using lowercase letters (ex: h, b, t)

That's a good review to enable you to work your way through the test if you lost your vocabulary sheet (which, I hope that you didn't!).

Everyone has done such a great job working with the Punnett Squares this week - every Junior Geneticist in Team 7A has been correctly identifying the genotypes of two parents, properly placing them on the outside of the Punnett Square and accurately crossing the parents to find the possible genotypes of their offspring. However, word problems (like the ones on your take home test) are a bit trickier....here are a few steps to get you through them:

1. Identify what the question is asking you to do (underline or highlight it if necessary)

2. Identify the genotypes of the parents

3. Write the genotypes of the parents along the top and side of the Punnett Square (one allele along each box)

4. Perform the cross, including two alleles in each box

5. Determine the phenotypes of the offspring's possible outcomes (refer to the question to determine which form of the trait is dominant, and which is recessive)

6. Answer the question

Don't forget that I will be collecting the tests during homeroom on Monday (I will notify your homeroom teacher to collect them and give them to one of my homeroom students as the come around) so that 4th period does not have more time to work on it than 1st period does. I will not be accepting any tests in class Monday or on Tuesday. If the school attendance documents your late arrival, I will be accomodating, however, for all other circumstances, THERE WILL BE NO LATE WORK. Absences on Monday will be handled individually.

Get the test over and done with early, so that if you have any questions you can email me immediately and so that you can enjoy the remainder of your weekend without the test hanging over your head!

Have a great weekend!!! No more rain!! : P