HARD
AS and A Level
IMPORTANT
Earn 100
A cell with three sets of chromosomes is said to be triploid, 3n. A cell with four sets of chromosomes is said to be tetraploid, 4n. Could meiosis take place in a 3n or a 4n cell? Explain.
Important Questions on Inheritance
HARD
AS and A Level
IMPORTANT
A diploid (2n) chromosome number of Drosophila is 8. Copy and complete the table given below to show the different outcomes of the mitotic and meiotic division of a Drosophila cell.
| Mitosis | Meiosis | |
| number of division cycles | ||
| number of daughter cells | ||
| number of chromosomes per nucleus in daughter cells |
HARD
AS and A Level
IMPORTANT
Construct a genetic diagram to predict the chance that a child born to two parents, both with blood group AB, will have blood group B. Use the symbols IA and IB to represent the alleles.
HARD
AS and A Level
IMPORTANT
A woman with blood group A and a man with blood group B have a child with blood group O. Use this information to determine the genotypes of the woman and the man, and then construct a genetic diagram to explain how the child inherited her blood group. Use the symbols IA, IB and IO.
HARD
AS and A Level
IMPORTANT
A test cross was carried out between a brown rabbit and a white rabbit. Five brown offspring and one white offspring were produced. Use a genetic diagram to show how this indicates that the brown rabbit must be heterozygous.
HARD
AS and A Level
IMPORTANT
A test cross using a different brown rabbit produced four offspring, all of which were brown. Explain why this indicates that the brown rabbit may be homozygous.
HARD
AS and A Level
IMPORTANT
In a species of plant, the alleles for the tall stem is dominant to short. The two alleles for leaf colour, giving green or white in the homozygous condition are codominant, producing variegated leaves in the heterozygote.
A plant with tall stems and green leaves was crossed with a plant with short stems and variegated leaves. The offspring from this cross consisted of plants with tall stems and green leaves and plants with tall stems and variegated leaves with a ratio of 1 :1. Construct a genetic diagram to explain this cross.
HARD
AS and A Level
IMPORTANT
Distinguish between the terms genotype and phenotype.
HARD
AS and A Level
IMPORTANT
Distinguish between the terms homozygous and heterozygous.
