Monohybrid And Dihybrid Crosses

The term "phenotype" refers to the observable characteristics or traits of an organism. These traits can include physical features, such as eye color or height, as well as behavioral or physiological characteristics. The phenotype is determined by a combination of genetic factors and environmental influences. It is what can be seen or observed in an organism, as opposed to the genotype, which refers to the genetic makeup or underlying genes of the organism.

The term "genotype" refers to the genetic makeup of an organism. It represents the specific combination of genes that an individual possesses. Genes are the units of heredity that are responsible for the traits and characteristics of an organism. Therefore, the genotype of an organism is the genetic information that is encoded in its genes. This information determines the physical and biological traits that an organism will exhibit.

A homozygous recessive plant has two copies of the recessive allele. This means that both of the plant's alleles for a particular trait are the same and are recessive. In genetics, alleles are alternative forms of a gene that determine specific traits. Recessive alleles are only expressed when an individual has two copies of the same recessive allele. Therefore, in this case, the plant has two copies of the recessive allele, resulting in the expression of the recessive trait.

When a purebred pea plant for height is crossed with a hybrid for height, the phenotypic ratio of 4:0 indicates that all of the offspring have the same phenotype as the purebred parent. This suggests that the trait for height is dominant and the hybrid parent is heterozygous for the trait. Therefore, the statement is true.

If the unknown plant's genotype is homozygous dominant, it means that both of its alleles for the gene in question are dominant. When this plant is crossed with a purebred recessive plant, all of the offspring will inherit one dominant allele from the unknown plant and one recessive allele from the purebred recessive plant. Since the dominant allele is always expressed over the recessive allele, all four of the offspring will have the dominant phenotype.

In a dihybrid cross, two traits are being crossed and the outcome can be determined by looking at the phenotypic ratios of the offspring. In this case, the traits being crossed are TtGg and ttgg. The genotype of the first parent is known, and the genotype of the second parent is known as well. Since the traits are not linked and are independently assorting, the outcome can be determined by looking at the possible combinations of alleles for each trait. This can be done without filling out the entire sixteen square table, as the phenotypic ratios can be determined from the known genotypes. Therefore, the statement is true.

The given question is asking for all possible combinations of alleles in the pollen of a pea plant with the genotype TtPp. The genotype TtPp represents two different genes, with T and t representing one gene and P and p representing another gene. Each gene has two alleles, uppercase and lowercase. The possible combinations of alleles in the pollen are TP, Tp, tp, and tP.

The given correct answer suggests that when a heterozygous green seeded plant is crossed with a purebred recessive for seed color, the phenotypic ratio is 2:2, meaning that there is an equal chance of obtaining green seeded plants and recessive plants. Similarly, the genotypic ratio is also 2:2, indicating that there is an equal chance of obtaining the heterozygous genotype and the recessive genotype.