High School SMILE Meeting
13 March 2001
Notes Prepared by Porter Johnson

Biology/Chemistry

Karlene Joseph (Lane Tech HS) Handout: Genetic Recombination
directed activities that review meiosis and genetics by employing small stackable block cubes [similar to LEGO^TM blocks]. We used 6 cubes for each of 6 different colors, and connected 3 cubes of the same color to represent chromosomes. Then we constructed an original parent cell by placing one chromosome of each color in a matrix of 3 pairs of "homologous" chromosomes, and assigned letters [alleles] to each color; [eg a, b, c, A, B, C]. Capital letters represent the dominant genes, and lower case letters represent recessive genes. We then simulated the following rearrangements.

Replication: Produce an system identical to the original---12 states altogether---2 now of each color.
Crossing Over: Trade one cube with another on a homologous pair to effect crossing over of one gene for 2 of 3 homologous pairs by detaching and re-attaching blocks of different colors within one homologous pair.
Independent Assortment: Line up your chromosome set as they would appear in metaphase I in meiosis. Separate the homologous chromosomes by independent assortment for the first meiotic division.
Gametes: Show the unique combination of genes each gamete will receive as they would in anaphase II of meiosis---second meiotic division.
Offspring: Two gametes fuse in fertilization to restore a diploid state and create a zygote, or new organism.

We indicated the dominant genes for each case.

Here is a list of human traits for which there are contrasting forms. Within each trait one form (eg oval versus round head shape) was arbitrarily chosen as dominant and the other recessive. The results of each person's "virtual offspring" (above) could then be converted into a "phenotype" by making interesting and usually humorous sketches of the faces.

*	Trait	Contrast
1	Head shape	Oval vs Round
2	Chin shape	Pointed vs Square
3	Eye shape	Round vs Almond shaped
4	Hair shape	Curly vs Straight
5	Nose size	Big vs Little
6	Ear size	Big vs Little
7	Earlobes	Large hanging vs Small attached
8	Eyebrows	Bushy vs Thin
9	Lips	Thick vs Thin

Sarah Brennan (Robeson HS) Handout: Stoichiometry Fudge Recipe
presented us with a fudge recipe consisting of powdered sugar, cocoa, butter, milk, vanilla. For one batch, here is a recipe that gives the amounts of ingredients required and the amount of fudge produced.

Ingredient:	Powdered Sugar	Cocoa	Butter	Milk	Vanilla	Fudge
Recipe	3 2/3 cup	1/2 cup	1/2 cup	1/4 cup	1 teaspoon	48 pieces

If we had only 1/4 cup of butter, we would scale this recipe down by a factor of 2:

Ingredient:	Pwdr Sugar	Cocoa	Butter	Milk	Vanilla	Fudge
#1	1 5/6 cup	1/4 cup	1/4 cup	1/8 cup	1/2 teaspoon	24 pieces

Now, supoose we had only 3 cups of sugar. We would multiply each of the amounts by the factor 3 / (3 2/3)= 9/11 to obtain

Ingredient:	Pwdr Sugar	Cocoa	Butter	Milk	Vanilla	Fudge
#2	3 cup	0.4 cup	0.4 cup	0.20 cup	0.8 teaspoon	39 pieces

Every good cook knows how to scale the proportions to vary the size of each batch. For Example, what are the other proportions if 5 cups of sugar are available. Simple; you just multiply by 5 / (3 2/3) =15 /11. The results:

Ingredient:	Pwdr Sugar	Cocoa	Butter	Milk	Vanilla	Fudge
#3	5 cup	0.7 cup	0.7 cup	1/3 cup	1 1/3 teaspoon	65 pieces

The principles of stoichiometry are identical to those of the culinary arts. Once you find the right proportions, you simply scale the amounts of ingredients to make the right size batch. For example, consider the reaction

2 H₂ + O₂ ---> 2 H₂O That is, two molecules of H₂ and one molecule of O₂ are required to make two molecules of H₂O. We can go from molecules to moles to grams just by using the molecular weights of the ingredients:

Ingredient Mol Wt	H₂ 2 gr/mole	O_{2 32 gr/mole}	H₂O 18 gr/mole
#1	2 molecules	1 molecule	2 molecules
#2	2 moles	1 mole	2 moles
#3	4 grams	32 grams	36 grams

Zoris Soderberg (Webster School) Introduction to Nutrition

Part A: She asked the question Where does your food come from? Do you like hot dogs, ham sandwiches, pork chops, or ribs?

She drew a picture of a pig, and marked these three regions

Region	Food Product
Hips and thighs	Ham
Under belly	Ribs
Top: backbone	Pork chops

[The rest of the pig gets ground up to make hot dogs!]

Zoris then took a bag of Fritos^TM corn chops and read these ingredients on the list:

corn
vegetable oil (corn or partially hydrogenated sunflower)
salt

Rates of diabetes and obesity are soaring among children as well as adults, and increasing levels of "fast food" intake are surely the cause. We should limit our intake of these "empty calorie" foods. Read the label; set a better table!

Part B: Zoris then handed out small [40 ml] new medicine bottles, which she got from a druggist. [Do not use old medicine bottles for this purpose!] Each bottle was half-full with an opaque liquid. We shook them vigorously until a watery substance separated from a solid residue. We had just made butter from cream. The whole process took about 5 minutes. We enjoyed spreading the butter on saltine crackers and eating. It was great!

Notes taken by Ben Stark and Karlene Joseph