In meiosis, haploid cells are created. The number of chromosomes depends on the original starting number. In humans, 23 etc
The cell cycle, or cell-division cycle, is the series of events that take place in a cell leading to its division and duplication (replication) that produces two daughter cell. In cells without a nucleus (prokaryotic), the cell cycle occurs via a process termed binary fission. In cells with a nucleus (eukaryotes), the cell cycle can be divided in three periods: interphase—during which the cell grows, accumulating nutrients needed for mitosis preparing it for cell division and duplicating its DNA—and the mitotic (M) phase, during which the cell splits itself into two distinct cells, often called "daughter cells" and the final phase, cytokinesis, where the new cell is completely divided. The cell-division cycle is a vital process by which a single-celled fertilized egg develops into a mature organism, as well as the process by which hair, skin, blood cells, and some internal organs are renewed.
After cell division, each of the daughter cells begin the interphase of a new cycle. Although the various stages of interphase are not usually morphologically distinguishable, each phase of the cell cycle has a distinct set of specialized biochemical processes that prepare the cell for initiation of cell division.
A biological process is a process of a living organism. Biological processes are made up of any number of chemical reactions or other events that results in a transformation.
Regulation of biological processes occurs where any process is modulated in its frequency, rate or extent. Biological processes are regulated by many means; examples include the control of gene expression, protein modification or interaction with a protein or substrate molecule.
Developmental biology is the study of the process by which organisms grow and develop, and is closely related to Ontogeny. Modern developmental biology studies the genetic control of cell growth, differentiation and morphogenesis, which is the process that gives rise to tissues, organs and anatomy, but also regeneration and aging,.
Eukaryotes are organisms with a true nucleus in which the DNA genome is enclosed in a double membrane (e.g. fungi, protozoans, vertebrates, higher plants), in contrast to prokaryotes (bacteria and blue-green algae) that lack a nuclear membrane. It may seem surprising, given the enormous accomplishments of molecular and evolutionary biology, but there is still no general agreement among biologists on the questions of how sex in eukaryotes arose in evolution and what basic function sex serves. Fundamental to answering these questions is achieving an understanding of the origin and function of meiosis. Meiosis is a key stage of the sexual cycle in eukaryotes. Meiosis is the stage of the sexual cycle in which a diploid cell, ordinarily having two complete sets of chromosomes, gives rise to haploid cells (gametes) each having one set of chromosomes. Two such gametes arising from different individual organisms may fuse by the process of syngamy (fertilization) to generate a new diploid individual, thus completing the sexual cycle.
Meiosis is ubiquitous among eukaryotes. It occurs in single-celled organisms such as yeast, as well as in multicellular organisms, such as humans. Eukaryotes arose from prokaryotes more than 1.5 billion years ago, and the earliest eukaryotes were likely single-celled organisms. To understand sex in eukaryotes, it is necessary to understand (1) how meiosis arose in single celled eukaryotes, and (2) the function of meiosis.
An immature ovum is a cell that goes through the process of oogenesis to become an ovum. It can be an oogonium, an oocyte, or an ootid. An oocyte, in turn, can be either primary or secondary, depending on how far it has come in its process of meiosis.