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. 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..

1. 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.

2. 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.
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.

3. Spindle is formed in prometaphase.