Scoring Rubric for Take-Home Assignment #4 Fall 2009
Refer to my key on the web following the due date for
more information concerning the chromosome drawings.
Question #1 Chromosomes (6
pts)
Did the student Properly illustrate and label the
following?
| homologous chromosome pair #12 |
1 point ____ |
| the two sex chromosomes |
1 point ____ |
| the PAH gene locus |
1 point ____ |
| the dominant alleles (PAH or just P)alleles |
1 point ____ |
| the recessive alleles (pah or just p) |
1 point ____ |
| sister chromatids |
1 point ____ |
Question #2 Meiosis and Independent assortment (6
Points)
Did the student properly illustrate and label the
following?
| Independent assortment at metaphase I (two
drawings). |
2 points ____ |
| Proper assortment of chromosomes at end of
meiosis I (four drawings). |
2 points ____ |
| Proper assortment of chromosomes into sperm
cells at the end of meiosis II (# of drawings may vary as long as all 4
TYPES of sperm combinations
are included) |
2 points ____ |
Question #3 The woman's Eggs (4 Points)
| We did not ask for further explanation so the
correct fraction or percentage is all that is needed. |
4 points ____ |
Question #4 Offspring prediction (4 Points)
| Correct probability (chance) that the
couple will have a boy who is heterozygous for the PAH gene locus? |
2 points ____ |
| There should be one or two Punnett squares
indicating the target genotypes or some logical explanation of the
cross to explain how the probability was derived. This could also be a
multiplication of probabilities of gender probabilities and PKU
probabilities. |
2 points ____ |
|
