Cell Structure and Function

Introduction

In biology, a cell is a membrane-bound unit that contains the basic molecules of life and is made up of which all living entities are made up of. A single cell, such as a bacterium or yeast, is frequently a complete organism in and of itself. As cells age, they develop specialised functions. These cells work together with other specialised cells to form the foundations of huge multicellular organisms like humans and other animals. Despite being far larger than atoms, cells are nonetheless incredibly small. Mycoplasmas, a type of bacteria, are the tiniest known cells; some of these single-celled organisms are as small as 0.2 m in diameter.

Characteristics of Cells

• The body of an organism is supported and structured by cells
• The cell’s interior is divided into distinct organelles, each of which is enclosed by its own membrane
• The nucleus (major organelle) stores genetic data required for cell reproduction and growth
• In the cytoplasm, each cell has a single nucleus and membrane-bound organelles
• Mitochondria, a double membrane-bound organelle, is responsible for the majority of the energy transactions required for cell survival
• Lysosomes break down waste products in the cell
• By synthesising certain molecules and digesting, guiding, and sorting them to their proper locations, the endoplasmic reticulum plays an important role in the cell’s internal organisation

Cytoplasm

It acts as a catalyst in biochemical reactions. It serves as a platform for the other organelles in the cell to function. The cytoplasm of a cell is in charge of cell proliferation, growth, and replication. Diffusion is a physical phenomenon that allows items in the cytoplasm to migrate over small distances.

Cytoskeleton

The cytoskeleton is a network of long fibres that maintains the structural integrity of the cell. The cytoskeleton performs a variety of tasks, including maintaining cell structure, enabling cell division, and allowing cells to move about. It also has a track-like system for regulating organelle and other substance transport within cells.

Cell Structure

There are numerous types of cells in an individual, including prokaryotic cells, plant cells, and animal cells. The cell’s size and shape range from millimetres to microns, and are mainly determined by the job it performs. Cells come in a variety of forms. They can be rod-shaped, flat, curved, concave, spherical, rectangular, oval, or other shapes. Only a microscope will be able to see these cells.

Structure and Functions of a Prokaryotic Cell

Capsule

The oily outer covering of the cell wall is known as the capsule. The capsule’s primary job is to keep the cell from drying up, as well as to protect it from external stresses.

Cell Wall

The cell wall is a stronger and more rigid framework that gives a cell its shape and protects its internal organelles. Between the capsule and the cell membrane, it is the intermediate layer.

Cell Membrane

The cell membrane is a fragile inner structure that regulates the entry and departure of any substance within the cell. It performs the function of a permeable membrane. It has a breadth of 5-10nm and aids in the oozing of proteins and the removal of waste materials.

Cytoplasm

It is the viscous membrane, which is lying in between the cell membrane and nucleoid. 

Nucleoid

The nucleoid is a cytoplasmic area that contains genetic material. A prokaryotic organism’s DNA is a single large loop located inside the nucleoid. It’s a crucial component in cell division.

Ribosome

Ribosomes are made up of RNA and proteins. Protein synthesis in the cell is aided by it. Inside the cytoplasm, they are the tiniest membrane.

Plasmids

Plasmids are the double-stranded DNA-carrying membranes of cells. In prokaryotic species, plasmids are uncommon.

Pili

It’s a bacterial cell’s thinnest tissue. They are made up of a protein complex called pilin and are primarily responsible for attaching to objects, especially during sexual reproduction.

Flagella

It is a helical membrane with a diameter ranging from 19 to 20 nanometers that plays a crucial part in an organism’s mobility from one location to another.

Structure and Functions of a Eukaryotic Cell

Plasma Membrane

Plasma membranes are semipermeable membranes that act as a cell’s barrier, protecting and dividing the cell from the outside environment.

Nucleus

The nucleus is surrounded by a double-layered Phospholipid bilayer wall. They serve as a storage facility for the cell’s genetic materials in the form of DNA, as well as a repository for all of the crucial information required for a cell’s management.

Nuclear Membrane

The nuclear membrane is a double membrane layer that surrounds the nucleus and controls the flow of resources in and out of the nucleus.

Nucleolus

The non-membrane-bound organelle within the nucleus is known as the nucleolus.

Mitochondria

Mitochondria are the two smooth membranes found in all eukaryotic cells. They are the cell’s powerhouse. It is quite important. Transforms glucose into ATP.

Endoplasmic Reticulum

Organelle with two membranes that divides the cell into parts. It is connected to the cell’s nuclear membrane. It is involved in protein synthesis, lipid and steroid production, calcium storage and regulation, and carbohydrate digestion. Rough and smooth endoplasmic reticula are the two types of endoplasmic reticulum.

Ribosome

The ribosome is located in the cytoplasm. They are the sites where ribosomal RNA and proteins are synthesised in the cells.

Golgi Bodies

This is a compressed membrane that is mostly employed to preserve the cell’s resources. This membrane also aids in the storage and transport of materials within the cell. As a result, it’s also known as a cell’s post office.

Lysosomes

Lysosomes are membrane-bound organelles that contain digestive enzymes that aid in the breakdown of macromolecules. The lysosome performs an important role in cell protection by eliminating foreign substances that enter the cell.

Cytoplasm

Cytoplasm is a jelly-like organelle found in the interior area of a cell. It performs an important role in maintaining a cell stable and distinguishing the cell organelles from one another.

Chromosomes

Chromosomes are rod-like structures made up of proteins and DNA. Chromosomes are also important in establishing a person’s gender.

Plant Cell Structure

Plant cells are eukaryotic cells, meaning they have a nucleus, are multicellular, and have progressive membrane-bound organelles. The form of these plant cells differs from that of animal cells, as do certain organelles that are only found in animal cells but not in plant cells.

Animal Cell Structure

Animal cells are eukaryotic cells, meaning they have a genuine nucleus and multicellular, membrane-bound organelles. Animal cells, like plant cells, share comparable organelles with the exception of the cell wall, chloroplasts, number of vacuoles, and other factors. The shape of an animal cell is irregular due to the lack of a cell wall.

Conclusion

Over time, people’s perceptions of cell structure have shifted dramatically. Cells were once thought to be simple membrane sacs containing fluid and a few floating particles, according to early biologists. Cells are vastly more intricate than this, according to today’s biologists.

In the human body, cells come in a variety of sizes, shapes, and types. The concept of a “generalised cell” is proposed for descriptive reasons. It incorporates characteristics from all cell types. A cell is made up of three parts: the cell membrane, the nucleus, and the cytoplasm, which sits between the two. The cytoplasm contains elaborate arrangements of fine fibres as well as hundreds, if not thousands, of tiny yet unique structures known as organelles.