Question

Describe the apparent differences that can be observed between the animal and vegetal poles in a frogs. At which cell stage will the first appear?

Answer 1

The main apparent differences that can be observed between the animal and vegetal poles in frogs are-

1. The upper hemisphere is the animal pole while the vegetal pole is at lower hemisphere.
2. The animal pole is dark-coloured or pigmented due to presence of pigment granules while the vegetal pole is light in colour.
3. The vegetal pole is yolk rich while yolk content is less in animal pole. Since animal pole contains less yolk, it include more cytoplasm and the egg nucleus.

Frog deposits its egg in water and the uneven distribution of yolk and proteins between the two halves in egg cell are prepatterned by mother frog. The deposited egg in water which is ready for fertilization is at metaphse of meiosis II.