Question

A diploid organism has a chromosome number 2n=6. How many chromatids will be present during metaphase of meiosis? Select one: O a. 3 b. 9 O c. 24 Od. 12 e. 6

Answer 1

the cell cycle progress as G1, S, G2, and M phase, during S phase the DNA replicates, so each chromosome has 2 sister chromatids attached to each other at the centromere, during prophase the chromatin condenses to form chromosomes, homologous chromosomes pair up and crossing over occurs between the non-sister chromatids, then during metaphase I the paired chromosomes align at the metaphase plate, so the number of chromatids= 2$\times$ number of chromosomes= 2$\times$6=12

so the answer is d) 12.