Human Reproduction Question 87
87. Amount of yolk and its distribution are changed in the egg. Which one is affected?
(a) Pattern of cleavage
(b) Formation of zygote
(c) Number of blastomeres
(d) Fertilisation
Show Answer
Answer : a
Hints & Solutions
(a) The pattern of cleavage is determined by the amount of yolk and its distribution. In holoblastic cleavage, the segmentation lines pass through the entire egg. Hence, it divides egg completely. Egg in this type of cleavage contains moderate to sparse amount of yolk. For example, frog, human egg. In meroblastic cleavage, the sedimentation lines do not completely pass through the egg and remain confined to a part of the egg. Hence, it does not divide the egg completely egg in this type of cleavage contains a large amount of yolk. For e.g. insects and birds.
