Cell Structures

In this section, we will consider the very building blocks of life. The structures within a single cell underpin every process in this website, and we will go through these in detail.

Firstly we will describe the structure and function of the nucleus. Every eukaryotic cell contains a nucleus. The nucleus has three main functions. These are gene expression, processing of pre-mRNA and compartmentalisation.  In addition, the nucleus contains a nucleolus within it, which is the primary site for ribosome synthesis

Next we will consider the mitochondria, famously entitled ‘the powerhouse of the cell’. Mitochondria are cell organelles with a typical size of 0.75-3 micrometers. They are found in most mammalian cells. They play an essential role by hosting the electron transport chain, responsible for synthesising ATP. They also host mitochondrial DNA which is inherited maternally.

Lysosomes are a key component in the effective function of human cells. Small and often overlooked, lysosomes work as part of the recycling system of the cell. In this article, we will look at the structure, synthesis and function of lysosomes, and their role in some pathologies.

The endoplasmic reticulum is the major site of synthesis in the cell. It is a system of flattened sacs (cisternae) that extend from (and are continuous) with the outer nuclear envelope – taking up a significant volume of the cell (over half of the membranous components in the cell).

The golgi apparatus is a membrane bound organelle found in most cells. It has a function in packaging proteins and is implicated in the secretory pathway. In this article we shall look at the structure and function of the golgi apparatus and its role in Wilson’s disease.

Cell membranes are responsible for a variety of important functions within the body, such as allowing control of the enclosed environment. In this article we shall consider the main functions of the cell membrane, the composition of membranes and clinical conditions in which a portion of the cell membrane is abnormal.

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Mitochondria

Diagram of a cell nucleus showing the nuclear envelope with outer and inner membranes, nucleolus, nucleoplasm, heterochromatin, euchromatin, nuclear pores, and surrounding ribosomes.

Nucleus

Diagram of the endomembrane system showing the nucleus, rough and smooth endoplasmic reticulum, Golgi apparatus, lysosome, secretory vesicles, nuclear envelope, nuclear pores, ribosomes, and plasma membrane.

Lysosomes

Electron micrograph showing smooth endoplasmic reticulum, indicated by an arrow.

Endoplasmic Reticulum

Illustration of the Golgi apparatus showing stacked, curved membrane sacs, surrounding vesicles, and the labeled trans face.

Golgi Apparatus

Diagram of a cell membrane showing a phospholipid bilayer with embedded proteins, cholesterol, glycolipids, carbohydrates, cytoskeletal filaments, extracellular fluid, and cytoplasm.

The Cell Membrane

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