Cell structure & function

Cells are essential components of life—every living organism, whether humans, plants, or animals, is made up of cells. They constitute the structural and functional unit of life and have some unique characteristics. Several features about the cell structure and function make them the basic tenets of every organism.

Structure of a Cell

Plasma membrane

The cell membrane, also known as the plasma membrane, is a thin jelly-like layer that encloses the nucleus and the cytoplasm. It serves to separate cells from one another and the surrounding elements. The plasma membrane is permeable, allowing materials and chemicals to travel within and out of the cell.

The cell membrane gives the cell its form and stiffness.

Cell wall

In addition to the cell membrane, in-plant cells, there is also a thick outermost layer called the cell wall. The cell wall is a rigid and stiff structure surrounding the cell membrane. This extra layer, which surrounds the cell membrane, is essential to protect the plasma membrane and cellular components.

The cell wall consists of cellulose, hemicellulose, and pectin. It gives structure and support to the cells while also shielding them from mechanical shocks and damage.

Cytoplasm

There is a jelly-like substance called the cytoplasm between the nucleus and the cell membrane, another crucial cell component. The cytoplasm contains several different parts or organelles that make up the cell. These organelles include mitochondria, Golgi bodies, ribosomes, and other structures.

Nucleus

Except for a small quantity of mitochondrial DNA and, in plant cells, plastid DNA, the cell nucleus contains the whole genome of the cell. To construct chromosomes, nuclear DNA is arranged in many long linear molecules in a complex with a wide array of proteins, such as histones. These chromosomes are organised in a way that promotes cell function. The nucleus is the cell’s control centre because it maintains the integrity of genes and governs the cell’s activities by regulating gene expression.

Nuclear pores are designed to regulate the nuclear transport of molecules across the envelope because the nuclear envelope is impermeable to giant molecules. The pores run through nuclear membranes, providing a pathway for larger molecules to be actively carried by carrier proteins while enabling tiny molecules and ions to pass freely. Large molecules such as proteins and RNA must pass through the pores for gene expression and chromosomal maintenance to occur.

Cell organelles

Ribosomes

Ribosomes are the cell’s protein-producing organelles. They are found circulating in the cytoplasm or anchored in the endoplasmic reticulum and are made up of two subunits. Ribosomes use two types of RNA as templates and instructions to make all sorts of proteins that are essential for the cell’s survival.

Endoplasmic reticulum

The endoplasmic reticulum (ER) is a membranous organelle with a partially shared membrane with the nucleus. The rough ER, packed with ribosomes and involved in protein production, is a section of the ER. The other section of the ER is known as smooth ER and is responsible for producing essential lipids (fats).

Golgi apparatus

The proteins from the rough ER are transferred to the Golgi apparatus (or Golgi complex) if they need to be modified further. The Golgi apparatus, like the ER, is made up of folded membranes. It looks for specialised “codes” in the amino acid sequences of proteins and alters them accordingly. These processed proteins are subsequently stored in the Golgi or packed into vesicles and transported to other parts of the cell.

Chloroplasts

Chloroplasts are organelles found in plants and algae. In these organelles, photosynthesis takes place. Chloroplasts contain chlorophyll, a pigment that absorbs sunlight and transforms water and carbon dioxide into glucose. Owing to chloroplasts, autotrophic animals may meet their energy needs.

Mitochondria

Mitochondria are organelles found in most eukaryotic cells and serve as the cell’s powerhouse. Mitochondria are the powerhouses of cellular respiration, turning glucose into the energy molecule adenosine triphosphate, also known as ATP. ATP fuels cellular functions by breaking high-energy chemical bonds. Mitochondria are widespread in cells that require a lot of energy to function, such as those in the liver and muscles.

Functions of a cell 

Structure and Support

You are aware that a house is constructed of smaller units like bricks. Similarly, an organism, too, is made up of smaller units called cells. Although some specialised cells, such as collenchyma and sclerenchyma, are present to provide structural support, all cells, in general, provide the structural foundation for all creatures.

Growth

Tissues in complex organisms such as humans are formed by simple cell replication. As a result, cells are in charge of an organism’s growth. Mitosis is responsible for the entire process.

Transport

Cells import nutrients used in the various chemical reactions that occur within them. A waste product is formed as a result of these operations. This waste product is then disposed of by the cells. Small molecules such as oxygen, carbon dioxide, and ethanol move through the cell membrane through diffusion, called passive transport. Larger molecules, such as proteins and polysaccharides, are transported into and out of the cell via active transport.

Energy production

Organisms require energy to carry out several chemical reactions. Plants obtain their energy through photosynthesis, whereas animals obtain their energy through respiration.

Metabolism

The cell is in charge of metabolism, which encompasses all of the chemical activities inside an organism to keep it alive.

Reproduction

Mitosis (in more evolved organisms) and meiosis (in less evolved organisms) are two processes that aid in cell reproduction.

Conclusion

So, in this article, we learned about cell structure & function, which are important topics in Biology. We hope this cell structure & function study material will help you in your studies. Remember, a cell is the basic structural and functional unit of all living organisms. Thus, it is the most important part of life.