Question

2. What are the significance of mitosis & meiosis? Explain meiosis – I (prophase- I)?

Answer 1

Answer:

hiii byy

Explanation:

com pot can the answer no

Answer 2

Answer:

Meiosis is the type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell.

Mitotic cell division is equational in nature while meiosis is a reduction division. Meiosis 1 separates the pair of homologous chromosomes and reduces the diploid cell to haploid. It is divided into several stages that include, prophase, metaphase, anaphase and telophase.

Different stages of meiosis 1

The different stages of meiosis 1 can be explained by the following phases :

Prophase 1

Metaphase 1

Anaphase 1

Telophase

Prophase 1

(1) Leptotene – The chromosomes begin to condense and attain a compact structure during leptotene.

(2) Zygotene – In zygotene, the pairing of homologous chromosomes starts a process known as chromosomal synapsis, accompanied by the formation of a complex structure called synaptonemal complex. A pair of synapsed homologous chromosome forms a complex known as bivalent or tetrad.

(3) Pachytene – At pachytene stage, crossing over of non-sister chromatids of homologous chromosomes occurs at the recombination nodules. The chromosomes remain linked at the sites of crossing over.

(4) Diplotene – Diplotene marks the dissolution of the synaptonemal complex and separation of the homologous chromosomes of the bivalents except at the sites of cross-over. The X-shaped structures formed during separation are known as chiasmata.

(5) Diakinesis – Diakinesis is marked by the termination of chiasmata and assembly of the meiotic spindle to separate the homologous chromosomes. The nucleolus disappears and the nuclear envelope breaks down.

I HOPE THIS ANSWER WILL USEFUL

MAKE ME AS BRAINLIST

THANK U