In: Biology
PART ONE 1-5
1. In the cross AaBb X aaBb, what are the gametes for AaBb?
2. What is the genotype of a white-eyed male fruit fly?
3. Suppose you count 40 green tobacco seedlings and 2 white tobacco seedlings in one agar plate. do your results show that both parent plants were heterozygous for the color allele? Explain your answer.
4. Suppose that students in the laboratory periods before you removed some of the purple and yellow corn kernels on the ears of corn as they were performing the Experimental Procedure. What specific effects would this have on your results?
5. In the cross AaBb X aaBb, what are the genotypic (not phenotypic) results for this cross (be sure to include numbers of each)?
PART 2 6-10
6. In the cross AaBb X aaBb, what are the gametes for aaBb?
7. Suppose you count tobacco seedlings in six agar plates, and your data are as follows: 125 green plants and 39 white plants. What is the phenotypic ratio?
8. If a cross results in 90 long-winged flies to 30 vestigial-winged flies, what are the phenotypes of the parents?
9. If you count 52 purple rough corn kernels and 50 yellow smooth corn kernels, how many purple smooth corn kernels should you expect to count? How many yellow rough corn kernels should you expect to count? Explain your reply. (Hint: Remember our calculated ratios from the activity in class. How would you turn those ratios into actual counts?)
10. If offspring exhibit a 9:3:3:1 phenotypic ratio, what are the genotypes of the parental (P) generation?
1). AB, Ab, aB, ab for AaBb and aB, ab, aB, ab for aabb.
2). XrXr genotype shows inherited recessive allele from both of the parents which is the only way to have white eye fly.
3). Yes, to have two recessive tobacco seeds we need to have the recessive traits first. Because the heterozygote allele is also a combination of one dominant and one recessive allele.
4). It would affect our phenotypic ratio and genotypic results. The amount that is set for each color would not be perfect.
5). In the cross AABb X aaBb, the genotypes obtained are AaBB, AaBb, Aabb, and aabb in a ratio of 1:2:1:1.
6. Gametes for aaBb will be aB, ab.
7). The phenotypic ratio will be 3:1. 125/39 = 3.2/1 or 3/1 = 3:1.
8). The phenotype will be LL (longed winged) or Ll (heterozygote) longed winged.
9). The ratio of the phenotype is expected to be 9:3:3:1.
where
9 The phenotype of smooth-purple corn,
3 The phenotype of rough-purple corn = 52, 3Phenotype of smooth-yellow corn = 50 and 1Phenotype of rough-yellow corn.
Let the 1st ratio be x.
So, (3x + 3x) = 102
or , 6x = 102
or, x = 17.
Also, 9x = 153.
Thus, No. of smooth-purple corn = 9x = 153.
No. of rough-yellow corn = x = 17.
10). AaBb AaBb