Question

Explain 3 concepts for each compartment of the Venn diagram on the next page. (18pts)

Topic:

Cell signaling to cell division

(compare and contrast)

Answer 1

Ans: The concept of the Venn diagram can be explained by considering three simple examples such as a group of people who play baseball called 'a' while the other group of people plays hockey called as 'b' and a final group of people who like to play soccer called 'c'. These three sets can be represented in the form of a Venn diagram. as three circles which can be represented as intersecting each other. Further, when we study it compartments, we can understand the following concepts:

1. Union: The elements of the sets that are common can be mentioned in the union of sets. It contains all elements. eg. people who play either baseball or hockey or soccer

2. Intersection: It represents overlapping of the sets and can be explained as people who can play baseball and hockey and soccer

3. Difference: It represents that some people play baseball and hockey but not soccer so the one needs to unite only those people only baseball and hockey and subtract those who also play soccer. The same can be explained in the case of people having a choice other than that of explained earlier.

Cell Signaling: It is the biological process of cellular communication which may be of three types: autocrine, paracrine, and endocrine. The autocrine cell signaling occurs when a particular cell secretes a signal molecule and binds on the receptor of the same cell. As a result, a cascade of molecular reactions starts within that cell. In the case of paracrine signaling, signal molecules produced by one cell may travel nearby and may bind to the receptor of cells present in the vicinity. While in the case of endocrine signaling, the secreted signal molecules may travel through the bloodstream to longer distances and can bind to their target cell receptor. This type of cellular communication is very specific in nature and may have long-lasting effects. The process of cell signaling is essential to maintain homeostasis, growth, metabolism, reflex action, development, metabolism, apoptosis, etc.

Cell division: The cell division in the case of eukaryotes especially humans is of two types: mitosis and meiosis. The mitotic cell division occurs in the somatic cells and is considered as the major type of cell division. The meiotic cell division occurs in either testis or ovary at a specific developmental stage. The mitotic division results in a generation of genetically identical cells thereby maintaining chromosomal numbers. While the meiotic cell division involving two rounds of cell division called meiosis I and meiosis II. During 1st meiotic stage, the homologous chromosomes of the parents come close to each other and undergo duplication (interphase). A cross over event occurs. The resulting cells divide in the second meiotic stage to form a gamete having a single set of chromosomes.

The similarities that could be explained in the case of both of these processes is that they require cellular messenger molecule to get activated and once they receive the proper chemical signal, cascade of molecular reactions start to occur. Both of them play a crucial role in the development of the human being throughout life. While discussing contrast or differences, cell-signaling is a continuous process and happens very fast in real-time. While the cell division occurs at a specific stage of the cell cycle. A cell can arrest itself in a particular stage/phase and can never divide throughout its life. e.g. neurons. The cell division is limited to specific generations i.e. up to 30 to 40. Beyond that, normal cell don't show cell division as such. It is called a Heyflick phenomenon.