a What is the purpose of mitosis b Identify morphological ch

a. What is the purpose of mitosis? b. Identify morphological changes during mitosis in the following cell structures: chromatin, chromosomes, chromatids, nucleolus, nuclear membrane, centrioles, and spindle. c. Explain how cytokinesis occurs in animal cells, compared to how it occurs in plant cells. d. What is the involvement of microtubules and microfilaments in moving chromosomes during mitosis and in forming a cleavage furrow during cytokinesis?

Solution

Answer:

Cell Structure

Changes

Chromatin

During the onset of prophase, chromatin fibers do condense into discrete chromosomes which can be seen through a light microscope.

Chromosomes

They are formed by detaching chromatin network and become long, thin, and a thread like structure.

Chromatids

They are the two separate longitudinal thread which are joined at the center of chromosome called centromere.

Nucleolus

It disappears during the early prophase.

Nucleolus membrane

It disappears and gets recover when the two daughter cells are formed

Centrioles

It takes place in development of spindle fiber in a cell division.

Spindle

Also called as spindle fiber which helps in formation of genetically identical daughter cells. Spindle is formed in prometaphase.

Plant cells

Animal cells

A mid body is absent

It is present

In it division occurs by the formation of cell plate.

Here, complete cleavage takes place.

It takes place passively.

It takes place actively.

It is centrifugal.

It is centripetal.

A row of vesicles is formed.

A row of vesicles is not formed.

Wall formation is present.        

Wall formation is absent

It determines structure of a cell.

It forms a dynamic cytoskeleton

It forms spindle apparatus to divide chromosomes.

It helps to move cell eg. Lamellipodia, Filopodia

It provides means of transport for vesicles.

Motor proteins help to transport intracellular organelles.

Whereas cleavage furrow is the emplacement of surface of the cell that leads cleavage process by which Cytokinesis takes place. Here, microtubules and microfilaments play a major role in occurrence of mitosis properly.