Reference no: EM132761299

Based What happens to each of the following during early cell division? The question is at thwe very bottom.

a) the size of the embryo

b) the number of cells that make up the embryo

c)the size of the cells within the embryo

Answer from your tutor:

Explanation:

a ) During early cell division, the cells do not grow between divisions. In essence, they get smaller and smaller. It is shown that many embryonic cells commit to a developmental fate when they become too small to divide unevenly anymore. Early in embryonic development, the cells switch from dividing asymmetrically (into daughter cells with different sizes and developmental fates) to dividing symmetrically (into identical cells with the same fate). The size of the cells seems to be what determines when that switch occurs.

b) Just after conception ( for the first 12 hours after conception), the fertilized egg remains a single cell. After about 30 hours , it divides from one cell into two. After some hours later, the two cells divide to become four. And at the end of 3 days, the fertilized egg cell shall have become a berry-like structure made up of 16 cells. In essence, the number of cells increases

c) After fertilization, a series of rapid cell divisions do occur that decrease the size of the cells with each subsequent division. This eventually produces a morula. It is therefore true for cleavage that the size of cells decreases since the interphase in cleavage division is short and does not necessarily need growth. The different cells derived from cleavage, up to the blastula stage, are called blastomeres. Eventually, the resulting blastomeres will become quite smaller in size when its number increases.

on the answers in these questions

What is the relationship between the size of the cells present in the embryo during early cell division?