BIOL lab II
1-A cross gives a 3:1 phenotypic ratio. What are the genotypes of the parents? 3:1. (heterozygous parents)
2- According to Mendel’s law of segregation, parents who both have the genotype Aa would produce what gametes?
A germ cell Aa undergoes meiosis
3-What is the genotype of a plant that produces green peas? Yellow peas are dominant.
Yy or yy when crossed with a heterozygote (Yy) will give some offspring that are green
4- To determine whether an animal with the dominant phenotype is heterozygous or homozygous, it is best to cross it with the SAME phenotype.
5- If you performed the Drosophila cross LL × ll, what phenotypic ratio would you expect among the offspring?
6- According to Mendel’s law of independent assortment, how many different types of gametes would an AaBb parent have? An AABb parent?
AaBb: AB, Ab, aB, ab (4)
AABb: AB, Ab (2)
7- What is the genotype of a homozygous long-winged fly that is heterozygous for gray body color?
8-What is the expected phenotypic ratio among offspring if both parents are heterozygous for both traits? 9 short, black | 3 short, red | 3 long, black | 1 long, red (9:3:3:1)
9- Why do you expect class data to be closer to the expected ratio than your individual data? It averages out.
10- What is the genotype of a white-eyed male fruit fly?
white eyed, male X r Y. white eyed, female X r X r
11- Which gender can have white eyes if the female parent is homozygous dominant for red eyes and the male parent has white eyes?
Male offspring have white eyes
12- What does a father always give his male offspring in X-linked genetic crosses? X-linked genes are never passed from father to son.
13- What is the phenotype of a tobacco plant with the genotype Cc? Phonotype of C