In this article, we will learn about cells, their components and their composition. We will also learn about the structural organisation of cells and the types of cells. After reading this article, readers will be able to tell the following:
What is cell?
What is the cell made up of?
What is the structural organisation of the cell?
Types of cell.
What Is a Cell Made Up Of Structure and Functions of Cell Organelles
A cell is the most fundamental structural and functional unit of all living things. A cell is a structure with organelles that perform the essential tasks it needs to survive. But not every cell is the same. Animal cells are very different from plant cells. One of their main distinctions is the absence of cell walls in animal cells.
Additionally, different cells have different sizes; the egg or female ovum is the biggest cell in the human body. It is around 1 millimetre across. Granule cells are the tiniest cells, about 4.5 micrometres in size, and are found in the human cerebellum.
Types of Cells
Eukaryotic and prokaryotic cells make up the majority of cells.
Prokaryotic Cell
The prokaryotic cell's primary characteristics are listed below.
Bacteria, mycoplasma, and blue-green algae represent them.
Different shapes multiply quickly.
It is the naked genetic material.
Organelles in cells are missing.
Except in Mycoplasma, the presence of a cell wall around the cell membrane.
The two components, the 50s and 30s of ribosomes, which are joined to form the 70s ribosomes and serve as locations for protein synthesis, are connected to the cell membrane.
Polyribosomes are ribosomes that chain together with RNA.
The cytoplasm contains reserved elements such as cell inclusion bodies.
The Eukaryotic Cell
The following lists the primary characteristics of eukaryotic cells.
Animals, plants, fungi, and protists all have eukaryotic cells.
Organelles bound to membranes cause the cytoplasm to be separated into compartments.
A well-organised nucleus enclosed by a nuclear membrane is present.
Chromosomes are structures that hold genetic material.
In addition to the membrane, plant cells also have a cell wall. In contrast to animal cells, they have a sizable central vacuole.
Animal cells have centrioles, which are distinctive.
The Structural Organisation of a Cell
We will now discuss the structural organisation of a cell in detail.
Cell Membrane
One crucial component of the cell is the cell membrane.
Composed of phosphoglyceride-containing lipids organised in a bilayer. Later, protein compounds were also found.
Proteins exist in two forms: integral protein, which is submerged in the membrane, and peripheral protein, which is exposed.
According to Singer and Nicholson's hypothesis, the membrane's quasi-fluid structure makes it possible for proteins to migrate across the bilipid layer.
The plasma membrane's main job is to guarantee that chemicals are transported.
Cell Wall
Cell Wall
The following is a list of the cell wall's properties.
It is composed of algae and plants.
Plants use cellulose, hemicellulose, and pectin to make their cell walls.
Galectins, minerals, and cellulose make up the algal cell wall.
Plants' main cell walls can't expand, therefore, once they reach maturity, they quickly change into secondary cell walls.
The endoplasmic reticulum, Golgi bodies, lysosomes, and vacuoles comprise the endomembrane system.
Endoplasmic Reticulum
Endoplasmic Reticulum
The endoplasmic reticulum is involved in some of the most crucial processes.
Ribosomes are not present on the surface of smooth ERs, which are involved in lipid production.
Rough ER: Produces and secretes proteins and has ribosomes on its surface.
Golgi Apparatus
Golgi Apparatus
The Golgi apparatus is a further crucial component of the cell.
It is a site of glycoprotein and glycolipid production.
Golgi Apparatus is involved in transporting and packaging materials.
Golgi Apparatus consists of parallel stacks of flat, disc-shaped cisterns.
Lysosome
Lysosome
The membrane-bound structure. It has an abundance of hydrolytic enzymes like lipase and protease that can break down proteins, carbs, and lipids.
Mitochondria
Mitochondria
The mitochondria are the next critical component of the cell structure. These characteristics are listed below.
Mitochondria are found in areas where aerobic respiration occurs.
Mitochondria produce ATP, which is the cellular energy currency.
The matrix comprises ribosomes, circular DNA molecules, RNA molecules, and protein synthesis-related molecules.
Plastids
Plastids
Another crucial component of the cell structure is the plastids.
Plastids are available in plant cells.
Plastids are organelles with a limited degree of autonomy and different genetic makeup.
Depending on the type of pigment discovered, there are three types. As follows:
Leucoplasts are nutrient-stored, colourless plastids of various shapes.
Chromoplasts: Because soluble lipids are present, they have a yellowish or reddish colour.
Double membranous structures are called chloroplasts. The term "stroma" refers to the inner membrane. The stroma contains stacks of thylakoids called grana. Enzymes for protein synthesis are present in the stroma.
Centrosome
Centrosome
This is a crucial component of the cell structure.
The centrosome consists of two centrioles, which are cylindrical structures.
The spokes are the peripheral fibrils in the hub of the centriole.
Nucleus
Nucleus
The nucleus is located further along in a cell's structure. It carries out several significant tasks.
It has chromatin, nuclear matrix, and nucleoli, which are extremely extended nucleoprotein fibres.
During cell division, chromatin material rearranges into chromosomes.
It consists of proteins and histones.
The centromere, or major constriction, is found at the centre of each chromosome on its disc.
Chromosomes can be classified as metacentric, submetacentric, telocentric, or acrocentric, depending on where the centromere is located.
Interesting Facts
The nerve cell are the only cell in the human body that will remain the same in number as they were at birth
Telomeres present at the end of each chromosome decide the life span of the cell.
All animal cells are self-sufficient, they have their own factory or machinery for the generation of essential components of the cell.
Every human cell divides in 24 hours.
Important Questions
1. How are cells formed?
Mitosis or meiosis is the process by which one cell divides to form other cells; during these divisions, the whole content of a cell duplicates and divides into two daughter cells.
2. Do all cells contain DNA?
Yes, all cells contain DNA as genetic material. All cells contain the full set of DNA required for that organism.
3. What is the structure of a cell?
There are three main parts of a cell, nucleus, cell membrane, and cytoplasm; other than this, many organelles are also present in the cytoplasm.
Practice Question
1. What is the structural organisation of a cell?
2. What is a cell made of?
3. Who discovered the cell?
4. What are the various functions of a cell?
Key Features
Cells are the fundamental biological, structural, and functional elements of all living organisms. A cell has the ability to reproduce on its own. They are, therefore, referred to as the basis of life.
The cell organelles are the cellular constituents. These membrane-bound cell organelles are located inside cells and have unique shapes and roles.
For the cell to function normally, they effectively coordinate with one another. A few of them give the cell structure and support, while others play a role in the cell's movement and reproduction.
FAQs on Cell Made Up Of and Structural Organisation of a Cell
1. What is a cell made up of?
A cell is made up of a cell membrane, cytoplasm, and genetic material, along with specialized structures called organelles. In detail:
- The cell membrane forms the outer boundary and controls the movement of substances.
- The cytoplasm is a jelly-like fluid where metabolic reactions occur.
- Organelles such as the nucleus, mitochondria, and ribosomes perform specific functions.
- In plant cells, a cell wall and chloroplasts are also present.
2. What is the structural organisation of a cell?
The structural organisation of a cell refers to the systematic arrangement of the cell membrane, cytoplasm, and organelles that work together to maintain life. It includes:
- An outer boundary (cell membrane or cell wall).
- Internal fluid matrix called cytoplasm.
- Membrane-bound organelles like the nucleus, endoplasmic reticulum, and Golgi apparatus (in eukaryotes).
- Non-membrane-bound organelles like ribosomes.
This organization ensures efficient coordination of cellular functions.
3. What are the main parts of a cell?
The main parts of a cell are the cell membrane, cytoplasm, and nucleus (in eukaryotic cells). These include:
- Cell membrane: Regulates entry and exit of substances.
- Cytoplasm: Site of metabolic activities.
- Nucleus: Contains DNA and controls cell activities.
In addition, cells contain organelles such as mitochondria, ribosomes, and vacuoles depending on the cell type.
4. What is the function of the cell membrane?
The function of the cell membrane is to act as a selectively permeable barrier that controls the movement of substances in and out of the cell. It:
- Maintains the internal environment of the cell.
- Allows nutrients and oxygen to enter.
- Removes waste products.
- Provides protection and structural support.
It is mainly composed of a phospholipid bilayer with embedded proteins.
5. What is the difference between prokaryotic and eukaryotic cells?
The main difference between prokaryotic cells and eukaryotic cells is the presence of a true nucleus and membrane-bound organelles in eukaryotes. Key differences include:
- Prokaryotic cells: No true nucleus, DNA in nucleoid region, no membrane-bound organelles (e.g., bacteria).
- Eukaryotic cells: True nucleus with nuclear membrane, membrane-bound organelles present (e.g., plant and animal cells).
- Eukaryotic cells are generally larger and more complex.
6. What is cytoplasm and what does it do?
The cytoplasm is the semi-fluid substance inside the cell that holds organelles and is the site of most metabolic reactions. It:
- Suspends cell organelles.
- Allows movement of materials within the cell.
- Contains enzymes required for biochemical reactions.
It plays a crucial role in maintaining the cell’s internal structure and function.
7. What is the role of the nucleus in a cell?
The nucleus controls all activities of the cell and stores genetic information in the form of DNA. It:
- Regulates growth and metabolism.
- Directs protein synthesis.
- Controls cell division.
The nucleus is surrounded by a nuclear membrane that separates it from the cytoplasm.
8. What are cell organelles and why are they important?
Cell organelles are specialized structures within a cell that perform specific functions necessary for survival. Important organelles include:
- Mitochondria: Produce energy (ATP).
- Ribosomes: Synthesize proteins.
- Endoplasmic reticulum: Synthesizes proteins and lipids.
- Golgi apparatus: Modifies and packages proteins.
Each organelle contributes to the overall structural organisation and functioning of the cell.
9. What is the function of mitochondria in a cell?
The mitochondria are responsible for producing energy in the form of ATP through cellular respiration. They:
- Break down glucose in the presence of oxygen.
- Release energy for cellular activities.
- Contain their own DNA and ribosomes.
Because of this role, mitochondria are often called the "powerhouse of the cell."
10. What is the difference between plant cells and animal cells?
The main difference between plant cells and animal cells is that plant cells have a cell wall, chloroplasts, and a large central vacuole, while animal cells do not. Key differences include:
- Plant cells: Have cell wall, chloroplasts for photosynthesis, large central vacuole.
- Animal cells: Lack cell wall and chloroplasts, usually have small vacuoles.
- Both contain nucleus, cytoplasm, mitochondria, and cell membrane.
In this article, we will learn about cells, their components and their composition. We will also learn about the structural organisation of cells and the types of cells. After reading this article, readers will be able to tell the following:
What is cell?
What is the cell made up of?
What is the structural organisation of the cell?
Types of cell.
