Genetics Monohybrid Crosses Worksheet Answer Key Introduction:
Genetics is an exciting and ever-evolving field that helps us understand how living organisms inherit traits from their parents. Monohybrid crosses are experiments conducted to study the inheritance of only one trait between two parents. A genetics monohybrid cross worksheet is a great tool to help students understand these concepts better. This worksheet enables students to practice solving problems on genetics, using the Punnett square method and making predictions about the inheritance pattern. In this comprehensive guide, we will provide you with the answers to the genetics monohybrid crosses worksheet.
Question 1: In green peas, the allele for green cotyledons (G) is dominant over the allele for yellow cotyledons (g). Two heterozygous (Gg) green pea plants are crossed. What is the probability of offspring with green cotyledons?
Answer: There are four possible gametes that can be formed by each parent, namely G or g. When we cross the two parents, we draw a Punnett square and get a ratio of 1:2:1 for GG, Gg, and gg, respectively. The probability of offspring with green cotyledons(GG or Gg) is ¾ or 0.75 or 75%.
Question 2: In guinea pigs, black coat color (B) is dominant over white coat color (b). A black guinea pig is crossed with a white guinea pig, and all their offspring are black. What are the genotypes of the parents?
Answer: Since all offspring are black, the black guinea pig must have genotype BB, and the white guinea pig must have genotype bb. The cross would be Bb x bb. All F1 offspring will be heterozygous (Bb), and hence, black.
Question 3: In fruit flies, eye color is linked to gender. White eyes (w) are recessive to red eyes (W). If a male fruit fly with red eyes is crossed with a female with white eyes, what will be the phenotype ratio of the offspring?
Answer: Since the white eye is a recessive trait, only the homozygous recessive female (ww) and the heterozygous female (Ww) can exhibit the trait. The red-eyed male must be homozygous for the dominant allele (WW). When we cross WW with Ww or ww, we get all daughters with red eyes (Ww) and all sons with white eyes (ww). The phenotype ratio will be 1:1 for white-eyed sons and red-eyed daughters.
Question 4: In humans, the allele for tongue rolling (R) is dominant over non-tongue rolling (r). A man who can roll his tongue has a non-tongue-rolling father. What is the genotype of the man?
Answer: The non-rolling father must have the genotype rr. If he cannot roll his tongue, he does not have any dominant alleles. The man can roll his tongue, which means he must have at least one R allele. So, his genotype must be Rr.
The genetics monohybrid crosses worksheet is an essential tool for students to learn about inheritance patterns and the Punnett square method. Solving these problems helps students to hone their analytical and critical thinking skills, leading to a greater understanding of genetics concepts. In this comprehensive guide, we have provided you with the answers to the genetics monohybrid crosses worksheet, helping you to understand the solutions to the problems and the underlying principles. We hope this guide has been useful, and that you can now confidently tackle any similarly structured questions on genetics and excel in your studies.