During the first and second cell divisions during early embryogenesis, some moll

Question

During the first and second cell divisions during early embryogenesis, some mollusk embryos produce a cytoplasmic protrusion called the polar lobe. This polar lobe is preferentially absorbed into the D blastomere lineage following mitosis. Removal of the polar lobe or the D blastomere results in the development of incomplete larvae that lack the intestine, meosodermal organs such as the heart and some muscles and also some ectodermal organs such as the eyes.

Describe an experiment to determine if the role that you have hypothesized for the polar lobe is necessary for the normal patterning of the mollusk embryo (loss-of-function, “block it”).

Describe a result that is consistent with your hypothesis.

Describe a result that is inconsistent with your hypothesis.

Describe an experiment to determine if the role that you have hypothesized for the polar lobe is sufficient to pattern the early mollusk embryo (gain-of-function, “move it”).

Describe a result that is consistent with your hypothesis.

Describe a result that is inconsistent with your hypothesis.

(A) Clear animal cytoplasm Granular equatorial cytoplasm AB Clear vegetal cytoplasm Polar lobe AB CD AB CD Polar lobe absorbed into CD blastomere Second polar lobe extrusion Polar lobe absorbed into D blastomere

Explanation / Answer

ans-1 the following experiment can be performed to observe loss of function

the polar lobe of the mollusk embryo should be removed by using specific tools and one other mollusk should be grown as a control sample. the result can be interpreted by observing thr growth of the both larva.

ans-2 the consistent result will be as follows

the mollusk embryo without polar lobe will not grow properly and will lacking some of internal organs while the control will grow normally.

ans-3 the inconsistent result will be that the control and subject samples will develop normally.

ans-4 this can be achieved by taking some mollusk with polar lobe(considered as subject 1)and some mollusk without polar lobe(considered as subject 2) then the polar lobe should be removed from the subject 1 and should be transferred to the embryo which were not having polar lobe or subject 2. then the result should be interpreted by observing the development of embryo.

ans-5 the consistent result will be if the subject 2 develop normally and having all the organs in proper growth.

ans-6 the inconsistent result will be if the subject 2 doesnot develop properly and having some missing organs.

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