SNHS Biology Blog 4: Cell Organelles

Andrew Park

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Cells are one of the most important topics in Biology, as they make up all living organisms. There are two types of cells: prokaryotic cells and eukaryotic cells. Both types of cells have a membrane, DNA, and ribosomes. However, eukaryotic cells have specialized membrane-bound organelles that have specific functions that help the cells stay alive.

Cell Membrane

The cell membrane is a very important type of organelle as they act as gatekeepers only allowing certain molecules to enter the cell. The cell membrane mainly consisted of phospholipids, which have a polar end and a nonpolar end. The phospholipids will create a bi-layer that puts the polar ends on the end and the nonpolar ends in between the polar ends. The nonpolar of the phospholipids prevents any large molecules, charged molecules, or polar molecules to pass through the membrane freely, but it will allow small, nonpolar molecules to travel freely through it. To allow important molecules like water and glucose into the cell, the cell membranes have proteins on it, allowing it to create a specialized channel or pumps that allow certain molecules to pass through the cell membrane.

Nucleus

The function of a nucleus is very simple but very crucial to the cell. The nucleus is like a blueprint and a commodore for the cell. The nucleus contains the genetic information, DNA, which is a blueprint to all cell functions. In the nucleus, the protein synthesis process will begin, where the mRNA will copy the DNA information to construct an appropriate protein.

Endoplasmic Reticulum/Ribosome

The endoplasmic reticulum (ER) is separated into two parts: the soft ER and the rough ER. The rough ER has ribosomes attached to it, and this is where the information in the mRNA is used to make proteins for the body. The soft ER makes lipids and steroids. In the ER, the produced protein will be “packaged” and will be sent to the golgi apparatus.

Golgi Apparatus

The golgi apparatus is where the produced and packaged protein would be given an identification. With the identification it received from the golgi apparatus, the proteins and other molecules made in the ER will be loaded onto transport vacuoles, which will move the produced particles to where they are needed.

Lysosome

The lysosome is the digestive organelle for the cell. It will take in the waste of the cell and use its digestive enzymes to discard the waste in the cell (mostly used up protein).

Mitochondria

The mitochondria is often described as the powerhouse of the cell. The mitochondria is where a process the cellular respiration takes place. This process will generate ATP energies that is necessary for many functions that the cell performs. The mitochondria has its own DNA, which suggests that they used to be free living cells once.

Vacuole

The vacuoles are the storage for the cell. The animal cells and plant cells both have the vacuole, but the size of the plant vacuole is significantly larger than the vacuoles in an animal cell.

Chloroplast

The chloroplast is one of the most important organelles. They are only present in the plant cells. This is where the process of photosynthesis happens, which produces glucose. Glucose is the source of energy for many organisms, which makes the production of it crucial for survival of many organisms.

Cell Wall

Cell walls are another structure that is only found in the plant cells. These walls are what gives the plants cells its rigid shape and it protects the cell. This structure does not contribute to the semi-permeable nature of the plant cells.

Cytoplasm

The cytoplasm is a structure that is found across all cells, regardless of its type. The cytoplasm is where the organelles are located, and it is also where a part of the cellular respiration takes place.