I can't figure out the correct answer for this, please help.
The drosophila embryo goes through a series of mitotic divisions before cytokinesis occurs. This demostrates one of the following.
1: cytokinesis is inextricably associated with mitosis
2. mitosis is always followed by cytokinesis
3: cytokinesis is never associated with mitosis
4: cytokinesis is inextricably associated with mitosis
Why are 1 & 4 the same?
2. is very often true, but not always.
So I guess 1 & 4
Cytokinesis is the division of the cytoplasm in a cell, which usually occurs immediately after nuclear division in mitosis. Cytokinesis is necessary to ensure a constant chromosome number in each cell. In mitosis, the chromosome number doubles, resulting in there being two sets of chromosomes in just one cell. The process of cytokinesis then results in two cells, each with their own single set of chromosomes. In animal cells, a process known as cleavage is undergone, in which the cytoplasm constricts at the centre. A ring of microfilaments (structural proteins polymerized in a helical form) forms in the middle of the cell, and as they constrict, the cell begins to pinch into two parts. As these parts separate, the cell surface shows very active movement, called “bubbling”. In plant cells, a dividing plate known as the cell plate forms across the centre, separating the two daughter cells, then forms a new cell wall. One notable exception to the normal process of cytokinesis is oogenesis (the creation of an ovum in the ovarian follicle of the ovary), where the ovum takes almost all the cytoplasm and organelles, leaving very little for the resulting polar bodies, which then die.
Source
http://en.wikipedia.org/wiki/Cytokinesis
The correct answer is 1 & 4, which are the same: "Cytokinesis is inextricably associated with mitosis."
As you mentioned, cytokinesis is the division of the cytoplasm in a cell, which usually occurs immediately after nuclear division in mitosis. However, there are exceptions where mitosis happens without cytokinesis, like in the drosophila embryo. This demonstrates that, although cytokinesis is typically associated with mitosis, they are not always inextricably linked, and mitosis is not always followed by cytokinesis. However, in the majority of cases, mitosis and cytokinesis occur together to ensure proper cell division and maintenance of chromosome numbers.
1 and 4 are the same because they both state that cytokinesis is inextricably associated with mitosis. This means that cytokinesis always occurs after mitosis and they are interconnected processes. Mitosis is the division of the nucleus in a cell, while cytokinesis is the division of the cytoplasm. In most cases, cytokinesis occurs immediately after mitosis to ensure that each new cell has a complete set of chromosomes.
Option 2 is not always true because there are instances where mitosis can occur without immediate cytokinesis. For example, in some situations, cells can undergo multiple rounds of nuclear division (mitosis) without undergoing cytoplasmic division (cytokinesis). This can lead to the formation of multinucleated cells.
To summarize, options 1 and 4 are correct because cytokinesis is indeed inextricably associated with mitosis, while option 2 is more of a general statement that is often true but not always the case.