Meiosis in spermatogenesis

Step 1

Primary spermatocytes  replicates its DNA and meiosis begins with 2n4c.

Step 2

Meiosis 1, homologous pairs of chromosomes lineup at the metaphase plate and crossing over occurs.

Step 3

Then the meiotic spindle pulls, one duplicated chromosome of each pair to the opposite pole of the dividing cell.

Step 4

The two cells formed by meiosis 1 are called secondary spermatocytes.

Step 5

Each secondary spermatocyte has 23 chromosomes, the haploid number (n).

Step 6

Each chromosome within a secondary spermatocyte is made up of two chromatids still attached by the centromere and now we are at 1n2c.

Step 7

No replication of DNA occurs in the secondary spermatocyte.

Step 8

In meiosis 2, we are still at 1n2c and the chromosomes lineup in a single file along the metaphase plate and two chromatids of each chromosome separate.

Step 9

The four haploid cells resulting from meiosis 2 are called spermatids.

Step 10

A single primary spermatocyte produces four spermatids with the haploid number (n) via two rounds of cell division with the haploid number (n).

Step 11

We end with 4 haploid cells and 1n1c.