Question

What is the ploidy of the embryo sac?

Answer 1

Hint: Ploidy refers to the number of homologous sets of chromosomes. Chromosomes are important elements that determine the genetic properties of the individual. If two sets of chromosomes are present then it is known as diploid and if one set is present it is known as haploid.

Complete answer:
Embryo sac refers to female gametophyte of a seed plant carrying a thin-walled sac inside the nucellus which in turn carries egg nucleus and other nuclei giving rise to endosperm on fertilisation. Embryo sac consists of three parts namely egg apparatus, secondary nucleus and antipodal. Antipodal in turn consists of three cells called haploids.

Embryo sac carries two haploid nuclei and six haploid cells that do not have any cell walls. Sometimes, haploid cells group together and combine to form a single cell called endosperm motor cell. The process ends with fertilisation under which male nucleus and female egg fuse together to form zygote which then turns into embryo after further development.

As ploidy is a concept of genetics which refers to the number of chromosomes occurring inside the nucleus of a cell. So the ploidy of the embryo sac is haploid.

Note: In the normal human body, chromosomes are present in pairs. These are known as diploids.
• Through the process of meiosis, the pair of gametes is produced by cells with each gamete containing half the number of chromosomes and thereby forms haploid.
• If these haploids again combine together then, diploids are formed.
• Chromosomes carry DNA of the cell and they ensure that DNA is accurately copied and is distributed widely in the majority of cell divisions.