Question

A cell that has a diploid number of 6 chromosomes has 3 chromosomes lined up in the center of the cell, each chromosome containing two joined sister chromatids. What phase of the cell cycle is this cell in?

a.Metaphase I of meiosis

b.Metaphase II of meiosis

c.Metaphase of mitosis

d.Telophase I of meiosis

Explain the answer please..

Answer 1

mitosis and meiosis are two types of cell division occuring in eukaryotic cells. mitosis produces two identical copy of cells. while meiosis produces 4 cells , it occur in genetic organs .

in mitosis the number of chromosomes in two newly produced cells will be equal. the stages of mitosis divided into 4 stages like prophase , metaphase , anaphase , telophase.

during prophase - cells prepare to divide by tightly condensating the chromosomes and initiate mitotic spindles, the chromosomes are thin , long thread like in this stage, each chromosome has two chromatids , and joined at the centromere. during late prophase a kinetochore , protienaceous microtubule binding structure that forms on the chromosomal centromere . number of polar microtubules find and interact with corusponding polar microtubule from the opposite centrosome to form the mitotic spindle.

during metaphase - the two centrosomes begins pulling the chromosomes towards oopposite ends of cells . the resulting tension causes the chromosomes to align along the equator plane , which is situated approximately the middle of cell. (option C is correct answer)

during anaphase - the cohesin , that bind sister chromatid together are cleaved , forming two identical daughter chromosomes. shortening of kinetochore microtubule pulls the newly formed daughter chromosomes to opposite ends of cell. during late anaphase , chromosome reach their maximal condensation level , to help chromosome segregation and the reformation of nucleus .

during telophase - the polar microtubules continue to lengthen , elongate the cells even further , a new nuclear membrane forms using membrane vesicle of parent cells old nuclear envelope. both the sets of chromosomes are now surrounded by new nuclear membrane , begins to relax or decondense.