Answer:
See explanation and attachment
Explanation:
This problem is assessing whether or not you understand the terms included. You can have a whole range of answers, this is an example of some answers I came up with!
Problem 1: Two tall pea plants produce hybrid pea plants that are both tall and small, at a ratio of 3:1 tall : small plants, how is this possible?
This is possible because the pea plants are heterozygous. The punnet square showing the genotypes is attached: 3 out of 4 possibilities are tall. 1:4 homozygous dominant, 2:4 (1:2 heterozygous) and 1:4 possibilities are small (homozygous recessive)
Problem 2: Problem 2: A dog homozygous recessive for a blonde coat (genotype bb) is bred with another dog that is heterozygous for a brown coat (genotype Bb). The owner wants to have some purebred pups that are blonde, what genotype will these dogs have, and what percentage of offspring can we expect to be purebred for the blonde trait?
The possible genotypes that arise from this cross are Bb and bb. In order for a dog to be purebred, they must be homozygous, and to have the blonde trait (which is recessive) must have two copies of the b allele. There is a 50% chance of offspring being bb, blonde, homozygous recessive, and purebred.
Problem 3: A plant with red flowers (RR) is crossed with a plant with white flowers (rr). The resulting plants from the offspring all have a pink phenotype. Explain how this could happen
A cross between two homozygotes (RR and rr) would give 100% offspring with an Rr genotype. This heterozygous genotype gives a pink phenotype. This phenomenon is called incomplete dominance. This arises when one allele is not expressed over the other, so a third, independent but intermediate phenotype is present, in this case as pink flowers.
Problem 4: A person with blood type A (AO) has a child with a person with blood type AB (AB). What is the percentage chance that their child will have blood type A, and what is the percentage change they will be homozygous blood type A.
Blood type is an example of a trait showing co-dominance. Both alleles are expressed equally. According to the punnet square, there is a 25% chance of the child having an AO genotype, 25% chance of them having a homozgous AA genotype, and 50% chance they will have blood type A phenotype
Problem 5: Two plants with round, green peas are crossed. There plants are heterozygous, R is the dominant allele for round, the recessive allele is r for wrinkled. G is the dominant allele for green peas, g is the recessive allele for white. Show the genotypes that could arise from this dihybrid cross. What is the ratio of the phenotypes that will arise?
The results of the dihybrid: cross are in the punnet square, the ratio of the phenotypes is 9:3:3:1 (round green: round white: wrinkled green: wrinkled white)
