Practice problems

1. You're working on golden rice, a plant that promises to alleviate nutritional deficiencies in some developing countries. You cross two true breeding plants. One parent is has fat grains, wavy leaves, red flowers and is short in stature, while the other parent expresses the contrasting phenotypes of thin grains, straight leaves, white flowers and is tall in stature. The four pairs of contrasting traits are controlled by four genes, each located on a separate chromosome. In the F1, only fat grains, straight leaves, red flowers, and tall stature were expressed. In the F2, all possible combinations of these traits were expressed in ratios consistent with Mendelian inheritance. (a) Wha... click for more

Genetics: man with type A blood x woman with type B blood

A man with type A blood marries a woman with type B blood. Their first child has type O blood. What proportion of his sperm have the IA allele? ______________ What proportion of her eggs have the IB allele? ______________ What is the chance that their second child will also have type O blood? Diagram this cross:

Biology problem

2. A true-breeding line peas with purple flowers, yellow pods, and green seeds (line A), is crossed to a true-breeding line with white flowers, green pods, and yellow seeds. The F1 all have purple flowers, green pods, and yellow seeds. How many loci involved in this cross?_________ A typical line A individual would exhibit how many different pollen genotypes?____________ How many types of gametes can the F1 plants make?________________ How many of the F2 are expected to exhibit all three recessive traits? ________ Diagram the cross below:

Biology problem

2.) A true-breeding line peas with purple flowers, yellow pods, and green seeds (line A), is crossed to a true-breeding line with white flowers, green pods, and yellow seeds. The F1 all have purple flowers, green pods, and yellow seeds. The F1 from the cross above are crossed to a line with white flowers, yellow pods, and green seeds. If 1000 offspring were scored for the three characters above, what number of offspring would be expected to have each of the eight possible phenotypes? List them below. (See attached file for full problem description)

Single gene cross: Line A is a true-breeding line of brown mice. Line B is a true-breeding line of white mice. A male from line A is crossed to a female from line B. The resulting F1 offspring are all black. The F2 offspring have black, white, and brown mice. What type of interaction between genes is this?

4. Line A is a true-breeding line of brown mice. Line B is a true-breeding line of white mice. A male from line A is crossed to a female from line B. The resulting F1 offspring are all black. The F2 offspring have black, white, and brown mice. What type of interaction between genes is this? What proportion of sperm from the F1 is expected to carry the allele for brown coat color? What proportion of black, white, and brown offspring would you expect in the F2?_________________ Diagram this cross: