CSET Topic Genetics,(Discussions and correct solutions)freshly 2025 |EDITION 1ST

Homozygous - term used to refer to an organism that has two identical alleles for a particular trait BB when a strain of fruit flies homozygous for light body color is crossed with a strain of fruit flies homozygous for dark body color, all of the offspring have a light body color. This illustrates the principle of? - dominance B dominance - An organism with a dominant allele for a particular form of a trait will always exhibit that form of the trait. (ex. Bb ---The big B would be dominant B segregation - (genetics) the separation of paired alleles during meiosis so that members of each pair of alleles appear in different gametes incomplete dominance - creates a blended phenotype; one allele is not completely dominant over the other independent assortment - states that genes for different traits can segregate independently during the formation of gametes and helps account for the many genetic variations observed in pants, animals, and other organisms heterozygous - term used to refer to an organism that has two different alleles for the same trait Bb recessive - The inherited characteristic often masked by the dominant characteristic and not seen in an organism. bb pure - having two like genes For a given trait, the 2 genes of an allelic pair are not alike. An individual possessing this gene combination is said to be? - heterozygous for that trait In peas, flowers located along the stem (axial) are dominant to flowers located at the end of the stem (terminal). Let A represent the allele for axial flowers and a represent the allele for terminal flowers. When plants with axial flowers are crossed with plants having termianl flowers, all of the offspring have axial flowers. Teh genotypes of the paretn plants are most likely: - AA x aa alleles - different forms of a gene autosomes - Chromosomes that do not determine the sex of an individual chromosomes - threadlike structures made of DNA molecules that contain the genes. phenotype - an organism's physical appearance, or visible traits the appearnce of a recessive trait in offspring of animals most probably indicates that: - both parents carried at least one recessive gene for that trait Which statement describes how 2 organisms may show teh same trait, yet have different genotypes for that phenotype? - one is homozygous dominant and the other is heterozygous In cabbage butterflies, white color (W) is dominant and yellow color (w) is recessive. If a pure white cabbage butterfly mates with a yellow cabbage butterfly, all the resuting (F1) butterflies are heterozygous white. Which cross represents the genotypes of the parent generation? - WW x ww homo - same BB hetero - different Bb WW x ww - kids heterozygous Ww to show dominant trait only need - one capitol letter W example of dominant trait - 6 fingers F P is dominant - p is reccessive Polydactyly is a characterstic in which a person has 6 fingers per hand. Polydactlyl is dominant over the trait for 5 fingers. If a man who is heterozygous for this trait marries a woman withthe normal number of finger, what are the chances theri child would be polydactly? - man is Pp and woman is pp Pp x pp equals Pp,Pp,pp,pp 50% chance A cross between 2 pea plants hybrid for a single trait produces 60 offspring. Approximatley how many of the offspring would be expected to exhibit the recessive trait? - Tt x Tt = TT, Tt, Tt, tt the tt is recessive 60 divide 4 is 15. In guinea pigs, black coat color is dominant over white coat color. The offspring of a mating between 2 heterozygous black guinea pigs would probably show a genotype ratio of: - 1 BB: 2 Bb: 1 bb 2 heterozygous Bb x Bb If a breeder wanted to discover whether a black guinea pig was homozygous (BB) or heterozygous (Bb) for a coat color, the animal in question would be crossed with an individual of what genotype: - bb In horses, black color is dominant over chestnut color. 2 black horses produce both black and a chestnut colored offspring. If coat color is controlled by a single pair of genes, it can best be assumed that: - both parent horses are heterozygous for hair color When a mouse with black fur is crossed with a mouse with white fur, all f1 generation offspring have gray fur. Which phenotypic results can be expected in the F2 generation. - 25% black, 50% gray, 25% white Explain how organisms can have the same phenotypes and different genotypes. - one mouse can be homozygous dominant BB and one is heterozygous Bb or hybrid. Humans have 23 pairs of chromosomes - how many pairs of chromosomes do humasn have?