Cells (Biology)

Cells (Biology)

Introduction

A cell is the smallest living unit of all organisms. There are two types of cells (i) unicellular, consisting of a single cell and (ii) multicellular organisms, where several cells are connected to a functional unit and they form a tissue. The human body consists of hundreds of different cell and different tissues. The science and study of the cells of living things is called the Cytology (Mader, 1998).

Each cell provides a structurally distinguishable, independent and self-maintaining system that is able to absorb nutrients and make their own energy through metabolism that is usable for them. One of the most important features in the cell is the ability to divide, and creating two new cells. The cell contains the information for all of these functions or activities. All cells have to be basic skills as features of life are referred to:

Propagation by division (mitosis or meiosis)

Material and energy exchange (food, construction of cellular structures or metabolic rate)

Response to stimuli (external or internal stimuli to abiotic factors such as temperature or food supply, to biotic factors such as predators, and many others)

Possibility of movement (in bacteria, for example, by the scourge, in animals with muscles , and in cells move proteins and vesicles )

Feature of the structured nature (morphology and dynamic)

Growth and development

Necrosis

Discussion

During evolution, two different groups of organisms have been formed, which differ greatly from the structure of their cells: first, the prokaryotes consisting of simple cells constructed without a nucleus, and secondly, the eukaryotes, which consist of cells that are essential complicated, structured and have a nucleus. Prokaryotes and eukaryotes could be a single cell as well as multicellular organisms. The multicellular form cells called syndicates. Mostly they share many features and are not individually viable. Due to the specialization in multicellular organisms, the above capabilities are limited.

Size of the cell

The dimensions of the cell vary from a few micrometers to a few tens. For this reason, a cell cannot be identified with the naked eye except for some special cases, such as eggs. For physiological reasons the cell cannot exceed a certain size. An increase of diameter of n times would result in an increase in the surface cell of about n² times, with consequent greater possibility of exchanges with the outside both in terms of nutrition and elimination of waste but also an increase in the volume of n³ times. The membranes of many ...