Author: Biology Junction Team

Identify the Controls and Variables

The Simpson’s Identifying  Controls and Variables

 

Smithers thinks that a special juice will increase the productivity of workers. He creates two groups of 50 workers each and assigns each group the same task (in this case, they’re supposed to staple a set of papers). Group A is given the special juice to drink while they work. Group B is not given the special juice. After an hour, Smithers counts how many stacks of papers each group has made. Group A made 1,587 stacks, Group B made 2,113 stacks.

 

 Identify the:

1. Control Group

2. Independent Variable

3. Dependent Variable

4. What should Smithers’ conclusion be?

 

5. How could this experiment be improved?
Homer notices that his shower is covered in a strange green slime. His friend Barney tells him that coconut juice will get rid of the green slime. Homer decides to check this this out by spraying half of the shower with coconut juice. He sprays the other half of the shower with water. After 3 days of “treatment” there is no change in the appearance of the green slime on either side of the shower.

 

 6. What was the initial observation?

Identify the-
7. Control Group

8. Independent Variable

9. Dependent Variable

10. What should Homer’s conclusion be?

 

 

 

Bart believes that mice exposed to microwaves will become extra strong (maybe he’s been reading too much Radioactive Man). He decides to perform this experiment by placing 10 mice in a microwave for 10 seconds. He compared these 10 mice to another 10 mice that had not been exposed. His test consisted of a heavy block of wood that blocked the mouse food. he found that 8 out of 10 of the microwaved mice were able to push the block away. 7 out of 10 of the non-microwaved mice were able to do the same. Identify the:
11. Control Group

12. Independent Variable

13. Dependent Variable

14. What should Bart’s conclusion be?

15. How could Bart’s experiment be improved?
Krusty was told that a certain itching powder was the newest best thing on the market, it even claims to cause 50% longer lasting itches. Interested in this product, he buys the itching powder and compares it to his usual product. One test subject (A) is sprinkled with the original itching powder, and another test subject (B) was sprinkled with the Experimental itching powder. Subject A reported having itches for 30 minutes. Subject B reported to have itches for 45 minutes. Identify the:
16. Control Group

17. Independent Variable

18. Dependent Variable

19. Explain whether the data supports the advertisements claims about its product.

Lisa is working on a science project. Her task is to answer the question: “Does Rogooti (which is a commercial hair product) affect the speed of hair growth”. Her family is willing to volunteer for the experiment.

 20. Describe how Lisa would perform this experiment. Identify the control group, and the independent and dependent variables in your description.

 

 

 

What Am I Doing Here?

POPULATION GENETICS PROBLEMS: HARDY-WEINBERG

POPULATION GENETICS PROBLEMS:  HARDY-WEINBERG EQUILIBRIUM

  1. A study on blood types in a population found the following genotypic distribution among the people sampled: 1101 were MM, 1496 were MN and 503 were NN. Calculate the allele frequencies of M and N, the expected numbers of the three genotypic classes (assuming random mating). Using X2, determine whether or not this population is in Hardy-Weinberg equilibrium.

 

  1. A scientist has studied the amount of polymorphism in the alleles controlling the enzyme Lactate Dehydrogenase (LDH) in a species of minnow.  From one population, 1000 individuals were sampled. The scientist found the following genotype frequencies: AA = .080, Aa = .280; aa = .640. From these data calculate the allele frequencies of the “A” and “a” alleles in this population. Use the appropriate statistical test to help you decide whether or not this population was in Hardy-Weinberg equilibrium.

 

  1. The compound phenylthiocarbamide (PTC) tastes very bitter to most persons. The inability to taste PTC is controlled by a single recessive gene. In the American white population, about 70% can taste PTC while 30% cannot (are non-tasters). Estimate the frequencies of the Taster (T) and nontaster (t) alleles in this population as well as the frequencies of the diploid genotypes.

 

  1. In another study of human blood groups, it was found that among a population of 400 individuals, 230 were Rh+ and 170 were Rh-. Assuming that this trait (i.e., being Rh+) is controlled by a dominant allele (D), calculate the allele frequencies of D and d. How many of the Rh+ individuals would be expected to be heterozygous?

 

  1. Phenylketonuria is a severe form of mental retardation due to a rare autosomal recessive allele. About 1 in 10,000 newborn Caucasians are affected with the disease. Calculate the frequency of carriers (i.e., heterozygotes).

 

  1. For a human blood, there are two alleles (called S and s) and three distinct phenotypes that can be identified by means of the appropriate reagents. The following data was taken from people in Britain. Among the 1000 people sampled, the following genotype frequencies were observed SS = 99, Ss = 418 and ss = 483. Calculate the frequency of S and s in this population and carry out a X2 test. Is there any reason to reject the hypothesis of Hardy-Weinberg proportions in this population?

 

  1. A botanist is investigating a population of plants whose petal color is controlled by a single gene whose two alleles are codominant. She finds 170 plants that are homozygous brown, 340 plants that are homozygous purple and 21 plants whose petals are purple-brown. Is this population in HWE (don’t forget to do the proper statistical test)? Calculate “F” (inbreeding coefficient) and explain what is happening in this population.

 

Click HERE for answers (but don’t go here until you’ve actually tried to answer these questions!)