Introduction:
Nucleosomes are the basic repeating units of chromatin, which is the complex of DNA and proteins that make up the chromosomes in eukaryotic cells. Each nucleosome consists of DNA wrapped around a core of eight histone proteins. The number of nucleosomes in a mammalian cell varies depending on the cell type and the stage of the cell cycle.

Number of Nucleosomes in Mammalian Cell:
The estimated number of nucleosomes in a mammalian cell is around 30-40 million. However, this number is not constant and can vary depending on the cell type, the stage of the cell cycle, and the level of chromatin condensation. For example, during mitosis, the chromatin condenses into highly compacted structures called chromosomes, and the number of nucleosomes is greatly reduced.

Factors Affecting Number of Nucleosomes:
The number of nucleosomes in a mammalian cell can be affected by several factors, including:

1. Cell type: Different cell types have different levels of chromatin condensation, which can affect the number of nucleosomes.
2. Stage of the cell cycle: During the S-phase of the cell cycle, when DNA replication occurs, the number of nucleosomes increases as new DNA is synthesized and wrapped around histones.
3. Cellular differentiation: During cellular differentiation, the chromatin structure can change, leading to alterations in the number of nucleosomes.
4. Environmental factors: External factors like temperature, pH, and osmotic pressure can also affect the number of nucleosomes.

Conclusion:
In conclusion, the number of nucleosomes in a mammalian cell varies depending on the cell type, the stage of the cell cycle, and the level of chromatin condensation. Despite this variability, the estimated number of nucleosomes in a mammalian cell is around 30-40 million.

In case of human , approximately 30 million nucleosomes can be present in haploid body .