An organelle is a structure within a cell (subcellular) that preforms one or more specific functions within the cell. This post lists some of the most important organelles and their functions.
Nucleus
The nucleus stores the genetic information (the DNA) of the cell as chromatin. The structure of a nucleus is shown below:
The nuclear envelope is a double membrane that surrounds the nucleus. The pores in the nuclear envelope allow things such as mRNA to pass out of the nucleus. Within the nucleus is the nucleolus and this is responsible for producing ribosomes.
Ribosome
Ribosomes are the site of protein production. They are very small and can be found attached to rough endoplasmic reticulum or float freely within the cytoplasm.
A ribosome is composed of ribosomal RNA (rRNA) and ribosomal proteins. They are split into two subunits – one small and one large. Unlike most organelles they do not have a membrane.
Smooth Endoplasmic Reticulum (sER)
Smooth endoplasmic reticulum is a system of membranes that that are filled with a fluid. The function of sER is to process lipids and carbohydrates.
Rough Endoplasmic Reticulum (rER)
Rough endoplasmic reticulum is similar in structure to sER but the surfaces are covered in ribosomes. The ribosomes are used to produce proteins which are then processed by the rER.
Mitochondria
The structure of a mitochondrion is shown below:
As shown in the diagram, mitochondria have a double membrane. The inner membrane folds to form structures called cristae. The space between the inner and outer membranes is called the intermembrane space and has an acidic pH.
Mitochandria are the site of aerobic respiration within a cell, the process that produces ATP. The space in the middle of a mitochondrion is called the matrix.
They are one of the largest organelles and contain DNA.
Vesicle
A vesicle is a small sac of fluid surrounded by a membrane. They are used to transport substances into and out of a cell and also between other organelles. They can be formed at the surface of a cell, by the endoplasmic reticulum or by the Golgi apparatus.
Golgi Apparatus
The Golgi apparatus is made up of a group of highly flattened, membrane bound sacs filled with fluid. Its function is to process and package proteins and lipids into vesicles that can then transport them. They are also responsible for producing lysosomes.
Lysosome
Lysosomes are round and surrounded by a membrane. They contain digestive enzymes that are used to digest old cell components (including lipids, proteins and nucleic acids) or invading cells. The cells can then use the products from the broken down components in the production of new substances. Lysosomes are acidic as the enzymes within them function in acidic conditions.
Centriole
Centrioles are hollow cylinders that contain a ring of small protein cylinders called microtubules. They are involved in the separation of chromosomes during the division of cells.
If you have any questions please leave them in the comments below. If you there are any topics that aren’t currently on the site that you’d like covering please let me know. You can stay up to date with new posts by following me on Pinterest and Instagram. You can search for more posts by clicking on one of the categories below or by using the search bar at the bottom of the page.