Mention the exact location of the following:
Aster:
Topic: Aster
Try it
Pick an option and check your answer. The full worked answer is below either way.
Answer
(b) Around the centrioles in animal cells.
The ASTER is the star-shaped array of radiating fibres that appears AROUND THE CENTRIOLES during cell division. (Aster means star.)
Two things must both be right, and the options test them separately: it forms around the CENTRIOLES, not the chromatids — which eliminates (c) and (d) it occurs in ANIMAL cells, not plant cells — which eliminates (a)
WHY NOT IN PLANTS: higher plant cells have NO CENTRIOLES at all, so they can form no aster. They still build a spindle, but without the star-shaped rays.
This is one of the two standard differences between plant and animal mitosis, the other being cytokinesis — by CELL PLATE from the centre outwards in plants, by FURROWING from the periphery inwards in animals.
Around the centrioles in animal cells.