In cucumbers normal leaves (N) are dominant to curled leaves (n) and elongated fruit (L) is dominant to spherical fruit and these genes are linked on the same chromosome. If a pure-breeding normal-leaved, elongated fruit cucumber is crossed with a curled-leaved, spherical fruit cucumber, what will be the phenotype of the F1? the phenotypic ratio of the F2?

1774

In cats yellow is due to gene B and black to its allele b. These genes are located on the X chromosome (sex-linked). The heterozygous results in calico (tortoise shell). What kinds of offspring (sex & color) are expected from the cross: black male & calico female? Most calico males are sterile, why?

2525

What is the chromosome number of Ginkgoes?

1667

How the chromosome region where the centromere is located is called? How are chromosomes classified in relation to the position of their centromere?

506

What are the substances that constitute the chromatin? What is the difference between chromatin and chromosome?

480

What is the relation between the concepts of chromatin and chromosome? Are euchromatin and heterochromatin part of chromosomes?

493

What are the primary and the secondary constrictions of a chromosome? What is the other name given to the secondary constriction?

473

What is the difference between chromatin and chromosome?

510

What is the other name given to sex chromosomes?

480

How are the concepts of chromosome, chromatin and chromatids related? In which phase of the cell cycle does dna duplicate?

474

What are homologous chromosomes? Which are the human cells that do not have homologous chromosomes?

481

What is the function of sex chromosomes?

497