What Are the Parts of the Cell Definition Structure and Functions
Do you know the egg of an ostrich is an example of the largest cell? And the cells which are present in our body are so small that can't be seen by the naked eye. What is the meaning of a cell? How these microscopic cells comprise our whole body. Do you know the types of cells and their functions? Do you know the different components of cells? Do you know the difference between plant cells and animal cells? Do you know bacterial cells are prokaryotic cells whereas human cells are eukaryotic cells? What is the difference between eukaryotic and prokaryotic cells? You will get answers of all these questions after reading this article. Human body cell structure is also explained below.
Cell Definition
The cell is the smallest functional and structural unit of all living organisms. All organisms are made of cells, a group of cells makes tissues, and a group of tissues makes organs.
What are the Types of Cells?
There are mainly two types of cells based on structure.
Eukaryotic cell
Prokaryotic Cells
These cells are found in lower or primitive organisms. These cells do not have a nucleus and the genetic material of these cells is suspended freely in the cytoplasm in a region called the nucleoid. These types of cells reproduce by asexual methods. The cell size is generally 0.1-0.5 micrometres. The hereditary material may be either DNA or RNA.
Eukaryotic Cells
These types of cells have true nuclei, and their size is between 10 and 100 micrometres. These cells can reproduce by both asexual and sexual methods. Eukaryotic cells involve animal cells, plant cells, fungi, and protists.
Structure of a Cell
The basic structure of a cell contains cell membranes, nuclei, cytoplasm, and various cell organelles.
All cell organelles are present in the cytoplasm of a cell.
Cytoplasm semifluid substance present between cell membrane and nucleus.
Different Parts of Cell and Functions
The following different parts of the cell and human cell function are explained below:
Nucleus - It is the main cell organelle and is also known as the master of the cell. It contains genetic material. The nuclear membrane is the outermost layer of the nucleus. Nuclear pores are present on the nuclear membrane to allow the movement of particles and molecules inside and outside of the cell.
Endoplasmic reticulum - Endoplasmic reticulum is also known as the palate particle in the name of discovery. It consists of membranes present inside the membrane.
It is of two types: Rough endoplasmic reticulum and smooth endoplasmic reticulum.
Rough endoplasmic reticulum - These are rough in appearance due to the presence of ribosomes on the surface of the endoplasmic reticulum. Rough endoplasmic reticulum synthesises protein and smooth endoplasmic reticulum is known as smooth because of an absence of ribosomes, which synthesise lipids, steroids, and other substances.
Mitochondria - These are sausage-shaped structures present in the cytoplasm. And synthesis of ATP molecules. It is also known as the powerhouse of the cell. It is a double membrane structure, an inner and outer membrane. Cristae are the fold of the inner membrane to increase the surface area. Matrix is the space present inside the inner membrane of mitochondria containing various types of enzymes and RNA.
Golgi Apparatus - These are the flattened and stacked pieces called cisternae and perform the functions of modifying, and packaging. It has two faces cis and trans. Various cisternae are held together by a matrix.
Lysosomes - These are membrane-bound organelles that contain a variety of enzymes that break biological polymers.
Human Cell Functions
The basic functions of the cell are given below:
Provide structural support.
Allow movement of substances inside and outside the cell.
Helps in reproduction through the process of meiosis and mitosis.
Cells contain mitochondria which help in energy production.
Help in the growth of organisms.
Cells of the Human Body
There are various types of cells in the human body depending on the structure and function they perform. Some examples of cells are provided below:
Blood Cells - There are different types of blood cells such as lymphocytes, leukocytes, and thrombocytes. Blood cells are produced from bone marrow.
Fat Cells - These cells contain or store fat droplets in the form of triglycerides. These are also known as adipocytes.
Nerve Cells - These cells comprise the whole nervous system. These are the basic units of the nervous system. Helps in the transmission of signals to and from the central nervous system. Contain a nucleus, cytoplasm, and some cell organelles.
Endothelial Cells - These cells form the innermost lining of the blood vessels. These cells make the new blood vessels.
Important Questions
1. Who discovered the cell?
Ans: The first dead cell was discovered by Robert Hooke in 1665 in the cork of bark. And first, the live cell was discovered by Leeuwenhoek.
2. What is the function cell?
Ans: The different functions of the cell are to provide structural support, convert food into energy, and also provide energy to various cells of the body. Cells also perform specialised functions for body cells.
3. What are cells made of?
Ans: Cells are made of various components: organic molecules, inorganic molecules, and water.
Interesting Facts
The ovum is the largest cell of the female human body.
A mature red blood cell does not have any nucleus.
The size of the longest neuron may be about 1m.
Plant cell does not rupture when placed over water.
Whenever there is damage to any organ of a pregnant woman, the foetus will send stem cells to regenerate the damaged organ.
Key Features
In this article, we studied cells, their types, and different examples of cells.
The cell is the structural and functional unit of living organisms.
There are mainly two types of cells: eukaryotic and prokaryotic.
Prokaryotes are the primitive type of cells whereas eukaryotes are the modern type of cells.
Important components of the cell are the plasma membrane, lysosomes, endoplasmic reticulum, mitochondria, etc.
The nucleus is known as the master of the cell.
Practice Questions
1. What is a cell mother?
2. Where do cells come from?
3. How many cells are in the human body?
4. Which organ is known as the mother of all cells?
5. Explain the human body cell structure.
6. What are different cell parts and functions?
FAQs on Parts of the Cell and Their Structure and Functions
1. What are the main parts of the cell?
The main parts of a cell are the cell membrane, cytoplasm, and nucleus (in eukaryotic cells).
- Cell membrane: Controls what enters and leaves the cell.
- Cytoplasm: Jelly-like fluid where organelles are found and reactions occur.
- Nucleus: Contains genetic material (DNA) and controls cell activities.
2. What is the function of the cell membrane?
The cell membrane protects the cell and regulates the movement of substances in and out of it.
- Made of a phospholipid bilayer with embedded proteins.
- Allows selective transport through diffusion, osmosis, and active transport.
- Maintains internal balance (homeostasis).
3. What does the nucleus do in a cell?
The nucleus controls cell activities and stores the cell’s genetic material.
- Contains DNA organized into chromosomes.
- Directs protein synthesis by regulating gene expression.
- Surrounded by a nuclear membrane with pores.
4. What is the function of mitochondria?
The mitochondria produce energy for the cell in the form of ATP (adenosine triphosphate).
- Site of cellular respiration.
- Break down glucose in the presence of oxygen.
- Known as the “powerhouse of the cell.”
5. What is the difference between plant and animal cells?
The main difference between plant and animal cells is that plant cells have a cell wall, chloroplasts, and a large central vacuole, while animal cells do not.
- Plant cells: Have a rigid cell wall and perform photosynthesis.
- Animal cells: Lack a cell wall and usually have smaller vacuoles.
6. What is the function of ribosomes?
The ribosomes are responsible for protein synthesis in the cell.
- Read instructions from messenger RNA (mRNA).
- Join amino acids to form proteins.
- Can be free in the cytoplasm or attached to the rough endoplasmic reticulum.
7. What does the cytoplasm do in a cell?
The cytoplasm is the jelly-like substance that holds organelles and supports cellular activities.
- Composed mainly of water, salts, and proteins.
- Site of many metabolic reactions like glycolysis.
- Helps transport materials within the cell.
8. What is the role of chloroplasts in plant cells?
The chloroplasts carry out photosynthesis to produce glucose from sunlight, carbon dioxide, and water.
- Contain the green pigment chlorophyll.
- Convert light energy into chemical energy.
- Found only in plant cells and some protists.
9. What is the function of the vacuole?
The vacuole stores water, nutrients, and waste materials inside the cell.
- In plant cells, the large central vacuole maintains turgor pressure.
- Helps keep the cell rigid and upright.
- In animal cells, vacuoles are smaller and more numerous.
10. What are organelles in a cell?
Organelles are specialized structures within a cell that perform specific functions.
- Examples include the nucleus, mitochondria, endoplasmic reticulum, and Golgi apparatus.
- Most organelles are membrane-bound in eukaryotic cells.
- Each organelle has a distinct role in maintaining cell function and survival.
