Cells are the smallest living units of an organism. There are many different types of cells in the world, but all cells have three things in common, no matter what type of cell they are. These three things are: a cell membrane, cytoplasm, and DNA. In this article, we will take a closer look at the different types of cells and the unique structures that they contain.
Types of Cells
There are two broad categories of cells: eukaryotic cells and prokaryotic cells.
Eukaryotic cells have organelles, which include the nucleus and other special parts. Eukaryotic cells are more advanced, complex cells, such as those found in plants and animals.
Prokaryotic cells, on the other hand, do not have a nucleus or membrane enclosed organelles. They do have genetic material, but it is not contained within a nucleus. Prokaryotic cells are always one-celled, or unicellular organisms, such as bacteria.
Organelles are the specialized parts of a cell that have unique jobs to perform. Some examples of organelles include:
- The nucleus: The control center of the cell. The nucleus contains DNA or genetic material. DNA dictates what the cell is going to do and how it’s going to do it.
- Chromatin: The tangled, spread out form of DNA found inside the nuclear membrane.
- The nucleolus: A structure where ribosomes are made.
- Ribosomes: After ribosomes leave the nucleus, they will have the important job of synthesizing, or making, proteins.
- The endoplasmic reticulum (ER): A membrane-enclosed passageway for transporting materials, such as the proteins synthesized by ribosomes.
- The Golgi apparatus (Golgi body): Receives proteins and other materials from the endoplasmic reticulum and customizes them into forms that the cell can use.
- Vacuoles: Sac-like structures that store different materials.
- Lysosomes: The garbage collectors that take in damaged or worn out cell parts.
- Mitochondria: The powerhouse for both animal and plant cells. They make ATP molecules that provide the energy for all the cells’ activities.
- Cytoskeleton: Maintains the cell’s shape through microfilaments and microtubules.
- Chloroplasts: Where photosynthesis happens in photoautotrophic organisms such as plants.
- Cell wall: Found in plant cells outside of their cell membranes, that shape, support, and protect the plant cell.
In addition to the organelles listed above, there are many other unique structures that only some cells have. For example, in humans, the respiratory tract is lined with cells that have cilia. These are microscopic hair-like projections that can move in waves. This feature helps trap inhaled particles in the air and expels them when you cough. Another unique feature in some cells is flagella, which are whip-like structures that help some organisms move.
Cells are incredibly complex and diverse, and they come in all shapes and sizes. Each type of cell has its own unique characteristics and structures that allow it to perform its specific functions. Understanding the different types of cells and the unique structures they contain is essential for understanding how living organisms work.
What are cells?
Cells are the smallest living units of an organism. They are the basic building blocks of life and come in many different types.
What are the three common things that all cells have?
All cells have a cell membrane, cytoplasm, and DNA.
What are the two broad categories of cells?
The two broad categories of cells are eukaryotic cells and prokaryotic cells.
What is the difference between eukaryotic and prokaryotic cells?
Eukaryotic cells have organelles, which include the nucleus and other special parts, and are more advanced and complex. Prokaryotic cells do not have a nucleus or membrane-enclosed organelles, and are always one-celled or unicellular organisms such as bacteria.
What are organelles and what is their function?
Organelles are the specialized parts of a cell that have unique jobs to perform. Examples of organelles include the nucleus, ribosomes, endoplasmic reticulum, Golgi apparatus, vacuoles, lysosomes, mitochondria, cytoskeleton, chloroplasts, and cell wall. Each organelle has a specific function that helps the cell carry out its functions.
Are there unique structures in some cells?
Yes, there are many unique structures in some cells. Examples include cilia, flagella, and other structures that help the cell perform specific functions.