Cell Structure

S Hoyland

Furness College

Channelside

Barrow-in-Furness

Cumbria LA14 2PJ

Introduction

The human body is made up of trillions of cells; these cells are the body’s living building blocks. The cells themselves, as with the human body, are highly organised and within their interior have many highly specialized organelles. Through the coordinated actions of these cellular components each cell has the ability to perform certain basic functions essential to its own survival and specialized tasks that contribute to the maintenance of homeostasis. The cellular components within the cell (organelles) reflect the metabolism of the cell and dictate the bodily system it will be associated with, these cellular variations are essential for the whole body’s survival. All body functions ultimately depend on the activities of the individual cells that compose the body.

A Basic Human Cell

Organelles within A Human Cell

Nucleus

The nucleus is one of the major parts of any individual cell and is also typically the largest, usually spherical in appearance and located towards the centre of the cell. Within the nucleus is the cells genetic material, deoxyribonucleic acid (DNA), which has two important functions. First,

the DNA provides instructions for directing the synthesis of proteins and enzymes within the cell. By directing the kinds and amounts of various proteins and enzymes that are produced, the nucleus indirectly governs most of the cellular activities and is therefore commonly known as the control centre. Second, DNA serves as a genetic blueprint allowing the cell to replicate and produce additional cells just like itself, continuing the specific cell line within the body. The nucleus is surrounded by a thin nuclear membrane, which allows substances to enter and leave through pores in its surface.

Figure 1 (www.molecure.com)

Endoplasmic Reticulum (rough and smooth)

The endoplasmic reticulum is a folded outgrowth of the nuclear envelope and consists of two distinctive types, smooth ER and rough ER. The two types differ in both their appearance and the function within the cell.

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Rough ER is a system of membranous sacs; these sacs give the rough ER a very large surface area due to their folded construction. It derives its name due to the fact it is coated with numerous ribosomes, which line the outer surface of its membrane, the large surface area allows more ribosomes to be attached. Rough ER is mainly involved with the production of proteins destined for export from the cell. The proteins are produced by the ribosomes coating the outer membrane and once the protein leaves the ribosome it enters into the lumen of the rough ER. Here ...

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