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92
In women, gametogenesis begins in fetal life, but is arrested in prophase of meiosis I for years until just before ovulation. This arrested oocyte is called the "primary oocyte". The human genome consists of 23 chromosomes, and normal somatic cells in humans have two of each chromosome (2N) in the resting state. Since the DNA in the primary oocyte has already replicated and but hasn't undergone division yet, the cell contains double the number of chromosomes of the original cell. Therefore the primary oocyte has 92 chromosomes (4N).
Keep in mind though, that just before ovulation, the cell will complete meisois I and be released as 2N (the other 2N is split off as the 1st polar body). This released cell (secondary oocyte) which is now 2N is arrested in metaphase of meiosis II until fertilized, where it will release a second polar body (which now only has 1N). The fertilized egg therefore has two copies of chromosomes, 23 from mother (from the original 92 you started out with), and 23 from the sperm.
What else can I help you with?
Is Oocyte haploid?
Unfertilized egg is haploid; but fertilized egg is diploid. That is why you sometimes see chickens even in commercial eggs.
Compare and contrast Primary oocyte and secondary oocyte?
Primary oocytes are diploid cells that have undergone DNA replication but are arrested in prophase I of meiosis, whereas secondary oocytes are haploid cells resulting from the division of primary oocyte after completing meiosis I. Secondary oocytes are arrested in metaphase II and are released during ovulation, while primary oocytes are present in the ovaries prior to puberty.
The process of creating an egg cell or oogenesis begins with one diploid cell and ends with?
The process of oogenesis begins with one diploid cell, known as an oogonium, which undergoes mitosis to produce primary oocytes. Each primary oocyte then undergoes meiosis, but it stops at prophase I until puberty. Upon hormonal stimulation, during each menstrual cycle, one primary oocyte completes meiosis I, resulting in a secondary oocyte and a polar body. The secondary oocyte then proceeds to meiosis II but only completes it if fertilization occurs, ultimately producing one mature egg (ovum) and another polar body.
In which stage is a primary oocyte arrested?
A primary oocyte is arrested in the prophase stage of meiosis I.
When a primary oocyte divides a secondary oocyte and what are produced?
A primary oocyte divides into a secondary oocyte and a polar body during meiosis I. The secondary oocyte undergoes meiosis II to produce a mature ovum (egg) and another polar body.
When the primary oocyte divides a secondary oocyte and what else is produced?
The primary oocyte divides into a secondary oocyte and a polar body during meiosis I. The secondary oocyte then goes through meiosis II to produce a mature ovum (egg) and another polar body.
What surrounds a primary oocyte?
follicle cells
A primary oocyte is closely surrounded by flattened epithelial cells called?
Primary oocyte is surrounded by flattened epithelial cells called follicular cells.
What forms part of the primary follicle in the ovary?
A primary follicle consists of a primary oocyte surrounded by a single layer of enlarged cuboidal epithelium. Recall that previously, there was a primary oocyte in a primordial follicle surrounded by a thinner single layer of squamous follicular cells.
What does follicle stimulating hormone promote the development of?
primary follicle/oocyte
During oogenesis an oogonium directly gives rise to what?
A primary oocyte
What is oogenessis?
This is the process by which eggs (ova) are made.It begins with the primordial germ cells (also called oogonium) which are diploid (have the full set of paired chromosomes). They divide by mitosis to produce primary oocytes. Then a primary oocyte undergoes a first meiotic division creating a secondary oocyte and a first polar body (which dies). Then after the second meiotic division of the secondary oocyte, an ootid (now haploid - i.e. has full set of unpaired chromosomes) results, along with a second polar body (which dies just like the first one). The ootid then develops into an ovum (egg).
