Question

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Answer 1

1.

IMAGE 1	STAGE	DESCRIPTION
A	PROPHASE	The nuclear material form long slender thread like chromosome are nit visible because they form a looseball of tangle and twisted.
B	METAPHASE	A later stage in which individual chromosome are much stronger than thicker and arranged on equatorial plane. Nucleus envelop discentagrated, sister chromatids.
C	ANAPHASE	A stage in which daughter chromosome are seperated groups at two opposite poles. The two seperated sister chromatids are daughter chrosomes. Microtubule attached and kinetochore is found to be shorted.
D	TELOPHASE	The polar migration of chromosome comes to end chromosomes to uncoil and gather into chromatin. Nuclear envelop reformed around the chromosomes.
IMAGE 2
A	CYTOKINASE	It is the final stage of the cell division by which the cell is divided into two. In plants the division of cytoplasm take place by cell plate formation in the middle of the cell
B	PROPHASE	The nuclear material form long slender thread like chromosome are nit visible because they form a looseball of tangle and twisted.
C	METAPHASE	A later stage in which individual chromosome are much stronger than thicker and arranged on equatorial plane. Nucleus envelop discentagrated, sister chromatids.
D	TELOPHASE	The polar migration of chromosome comes to end chromosomes to uncoil and gather into chromatin. Nuclear envelop reformed around the chromosomes.

2. Interphase is a period of great metabolic activity by hich the cell prepare itself for mitosis (cell division). It is called inter-mitotic phase. During this phase no cell division occurs, but nucleus and cytoplasms remain metabolically active and synthesis all substance required for the new daughter cells. Interphase again divided into three phase:- G₁ phase, S phase and G₂ phase.

G₁ phase:

• During this phase, cell synthesis all protein and enzymes required for DNA replication.
• Cell grows continously in this phase.
• Last for 11 hours.

S phase:

• DNA replication occurs in this phase.
• The chromosome duplicate and the site chromatids are help together at region of centromere.
• The chromosome are noe know as diads (since each chromosome duplicate).
• The chromosomes content of the cell has changed from 2n to 4n.
• This phase last for 8 hours.

G₂ phase:

• This place is also called post-DNA synthesis phase.
• Cell growth continous in this phase.
• During this phase, the cell synthesis protein and enzymes required for cell division (M phase) to take place.
• Last for about 4 hours.

3. Significans of Mitosis

• Mitosis take place in somatic cell. The division results in the growth and development of the body of an organism.
• Mitosis ensure equal distribution of nucleus and cytoplasms between the daughter cells both qualitatively and quantitatively.
• The chromsome number is mainteined constant.
• Old and dead cell are replaced by mitosis.
• Mitosis helps in the asexual reproduction of certain organisms.
• It helps the cell in maintaining proper size.
• It helps in the repair of tissue.

4. It is the final stage of the cell division by which the cell is divided into two. In plants the division of cytoplasm take place by cell plate formation in the middle of the cell. The cell plate grows and fuses with the laeral wall of the cell. As a result complete new wall is formed between two nuclei and each daughter get's own cytoplasm and nucleus. In animal cell, cell plate is not formed. this constriction deepens and thus two daughter nuclei are formed.

5. The chromatid belongs to same chromosome are sister chromatids.

The picture shows that the sister chromatids

homologus chromosome centromere