Every cell has a membrane to protect its contents. Cells are complex and need many chemical reactions. In eukaryotic cells, there are special structures called organelles. These organelles are surrounded by membranes. They help separate different chemical activities. Some organelles can only be seen with an electron microscope.
The endoplasmic reticulum (ER) is a large network of membrane tubes and sheets. It looks like long tubes or round bags. There are two types of ER:
Rough Endoplasmic Reticulum (RER): It looks rough because it has ribosomes on its surface. Ribosomes are where proteins are made. The RER sends these proteins to different parts of the cell.
Smooth Endoplasmic Reticulum (SER): It does not have ribosomes. Instead, it helps make fat molecules (lipids). Lipids are important for cell function and also help build cell membranes.
Functions of ER:
The Golgi apparatus is made of flattened sacs called cisterns. It works like a post office for cells. It receives materials from the ER, modifies them, and packages them into vesicles for delivery.
Functions of the Golgi Apparatus:
Lysosomes are membrane-bound sacs containing digestive enzymes. These enzymes are made by the RER. Lysosomes act as the waste disposal system for the cell.
Functions of Lysosomes:
Mitochondria are known as the powerhouses of the cell. They have two membranes. The outer membrane is porous, and the inner membrane is folded, which increases surface area for reactions.
Functions of Mitochondria:
Plastids are found only in plant cells. There are two types:
Chloroplasts have membrane layers and stroma similar to mitochondria and also contain their own DNA.
Vacuoles are storage sacs for solids or liquids. They are small in animal cells and large in plant cells. Plant cell vacuoles can take up 50-90% of cell volume.
Functions of Vacuoles:
Organelles help keep the cell organized. They perform essential functions like respiration, obtaining nutrition, and removing waste. Organelles ensure the cell can grow, repair, and reproduce.
New cells form through cell division. This process allows organisms to grow and replace old cells. There are two types:
Mitosis: This is how most cells divide. One mother cell divides to form two identical daughter cells. This helps organisms grow and repair tissues.
Meiosis: This type produces gametes for reproduction. One cell divides twice to make four new cells. These new cells have half the number of chromosomes.
Remember, cells are like tiny factories, and organelles are the machines that help them work!
What is an organelle?
What is the main function of the endoplasmic reticulum?
What are the two types of endoplasmic reticulum?
What does the Golgi apparatus do?
What role do lysosomes play in the cell?
Why are mitochondria called the powerhouses of the cell?
What functions do plastids perform in plant cells?
What is the function of vacuoles in plant cells?
What type of cell division leads to growth?
Why do gametes have half the number of chromosomes?
