What is cellular level?

The cell is the basic structural and functional unit of living organisms. Understanding what happens at the cellular level provides insight into the fundamental processes of life. This article will provide an overview of cellular structure and function.

What is a cell

A cell is the smallest unit of life. It is enclosed by a membrane and contains the molecules and structures necessary to sustain life. Cells carry out all the processes needed for growth, reproduction, and responding to the environment.

Cell types and sizes

There are many different types of cells in nature. Cells can be classified into two broad categories: prokaryotic and eukaryotic. Prokaryotic cells, like bacteria, lack a nucleus and other organelles. Eukaryotic cells have a nucleus and organelles enclosed within membranes.

Cells come in a wide range of sizes. The smallest cells are mycoplasmas, which can be as small as 0.1 μm. The largest cells are ostrich egg cells, which can be 170 mm in diameter - that's visible to the naked eye! Human cells typically range from 10 to 30 μm.

Cell Components

The main components that make up a cell are the plasma membrane, cytoplasm, and nucleus. Let's look at each in more detail:

Cell membrane

The cell membrane envelops the cell and acts as a barrier between the interior of the cell and the outside environment. It is selectively permeable, allowing certain substances to pass through while preventing others. The cell membrane is composed primarily of phospholipids and proteins.


The cytoplasm is the gel-like material within the cell membrane and surrounds the organelles. It is comprised of a cytosol, a water-based solution, and the cytoskeleton, a network of protein filaments. The cytoplasm provides a fluid medium for chemical reactions and intracellular transport.


The nucleus is the command center of the cell, directing all cell activities. It houses the genetic material of the cell in the form of DNA. The nucleus is enclosed in a nuclear envelope with pores that regulate transport between the nucleus and cytoplasm.


Organelles are specialized structures that perform specific functions within the cell. Some of the main organelles are:


Mitochondria are known as the "powerhouses" of the cell because they generate energy in the form of ATP through cellular respiration. They have two membranes - an outer smooth membrane and an inner folded membrane called cristae.

Endoplasmic reticulum

The endoplasmic reticulum (ER) is a network of tubules and sacs involved in lipid synthesis, protein transport, and calcium storage. There are two types - rough ER has ribosomes attached, while smooth ER does not.

Golgi apparatus

The Golgi apparatus is composed of stacked flattened sacs and is important for processing and packaging proteins and lipids. It modifies, sorts, and transports molecules to target destinations.


Lysosomes contain digestive enzymes for breaking down waste materials, food particles, and damaged organelles. They act as the recycling and waste disposal system of the cell.


Peroxisomes participate in lipid metabolism, such as beta-oxidation of fatty acids. They also neutralize toxins and break down harmful hydrogen peroxide molecules.

The cytoskeleton

The cytoskeleton is a network of protein filaments that provide structure and shape to the cell. It also facilitates intracellular transport and is involved in cell division and movement. There are three main components:


Microfilaments are composed of actin and are the thinnest of the cytoskeletal filaments. They play a role in muscle contraction and cellular structural support.


Microtubules are hollow rods made of tubulin. They help form the mitotic spindle during cell division and serve as tracks for organelle transport.

Intermediate filaments

Intermediate filaments are rope-like fibers that bear tension and anchor organelles. They provide mechanical strength to cells.

Review of key points

  • The cell is the basic unit of life that carries out all vital functions.
  • Cells have a variety of components including a membrane, cytoplasm, and nucleus.
  • Organelles perform specialized jobs within the cell such as producing energy, synthesizing proteins, and breaking down waste.
  • The cytoskeleton provides structural support and enables cell movement.

Understanding the intricate workings of the cell provides the foundation for appreciating the complexities of life. Research at the cellular level continues to uncover new insights into health, disease, and biology.

In order to fully understand the meaning of the term cellular level, it is necessary, first of all, to discover the etymological origin of the two words that give it shape:
-Level derives from the Provençal "level" and this, in turn, emanates from the Latin "libella", which was used to refer to a small scale.

-Cellular, meanwhile, comes from the Latin "cellullaris", which can be translated as "related to cells" and which is the result of the sum of the following lexical components: the noun "cellula", which means "small cell" , and the suffix “-alis”, which is used to indicate “relative to”.
The cellular level is defined by the cells.
The organization of life
The life is organized in different degrees of complexity or hierarchy, known as organizational levels . These structures are studied by the different areas of biology.

Specifically, it is established that the levels of organization of matter are as follows: atomic, molecular, organular, cellular, tissue, organs, organ system, organism, population, community, ecosystem, biome and biosphere.
What is the cellular level
The cellular level is the one made up of cells . A cell, meanwhile, is the smallest structural and functional unit that can reproduce independently in a living being.
Cells are generally microscopic. They have a nucleus and a cytoplasm that are surrounded by a membrane .
Neurons are nerve cells that act at the cellular level of the body.
Cell types
No less important is to know that cells can be of two types:
-Eukaryotic cells, which are identified by the fact that their DNA is within a nucleus, separated from what is the rest of its structure.
-Prokaryotic cells, which are those that do not have a nucleus. This circumstance causes that the mentioned DNA is in the so-called nucleoid. This is not a structure as such but rather a part of what is the cytoplasm or cell body.
The cell level in a pyramid
If we place the different levels of organization in a pyramid, the cellular level would be above the subatomic particles , atoms and molecules , which are not considered "living" . Immediately above it would have the tissues .

It can be said that a cell is made up of molecules, which are groupings of atoms (in turn made up of subatomic particles). Cells, for their part, are organized into tissues , which constitute organs . Some examples of what is the cellular level can be both the so-called pulmonary alveoli as well as the epithelial cells that are the ones that are lining the blood vessels.
From the cellular level, in short, one can go upwards: continuing with the increase in the complexity of each element, the organs are grouped into systems , which make up the organisms . These organisms can meet in populations , which give rise to communities . Those communities that are in the same physical environment create an ecosystem . Finally, the set of ecosystems is called the biosphere .
Importantly, metabolism develops at the cellular level . This process allows the degradation and synthesis of substances that the body takes advantage of or uses in various ways. All living beings , in any kingdom, are made up of cells that fulfill these types of functions.

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