Question

Blastomeres within the developing embryo while travelling through the fallopian tube
Statement 1: decreases in size
Statement 2: cytoplasm volume to nuclear volume ratio increases
Statement 3: the nuclear volume to cytoplasm volume ratio increases
Statement 4: potency increases

Choose the correct statements

• A. 1and 2 only
  
• B. 2 and 3 only
• C. 1 and 3 only
• D. 1, 2, 3 and 4
  

Answer 1

The correct option is C 1 and 3 only

Fertilization is a process of fusion of mature male and female gametes to form a single cell called the zygote. While moving towards the uterus, the zygote divides constantly. This division results in the formation of a multicellular stage called morula. The cells formed are called blastomeres.
Further divisions and rearrangements of the cell in the morula transform it into blastocyst. These divisions of the zygote are called cleavage. Until the blastocyst hatch from the zona pellucida layer, the actual size of the zygote remains the same but the number of developing blastomeres inside the cytoplasm keeps on increasing. As the same amount of the mass of the cytoplasm is getting divided into the increasing number of blastomeres, the cytoplasmic volume to nuclear volume ratio keeps on decreasing, hence the nuclear volume to the cytoplasmic volume ratio increases.
Since the blastomeres are constantly dividing as they travel through the fallopian tube, their size decreases.

Potency is the property of a particular cell, to give rise to multiple distinct cell types or a whole organism. In humans, the only true totipotent cell is the single-celled zygote. Potency starts gradually decreasing in embryonic cells as they get differentiated into germ layers in the gastrula stage.