I created a cake that represents an animal cell with all of its associated organelles.
The cell membrane is composed of a phospholipid bilayer. Phospholipid molecules have a phosphate group as the “head” and a lipid “tail.” The phosphate group is polar and negatively charged; this makes the phosphate group hydrophilic. The lipid tail, consisting of saturated and unsaturated fatty acids, is nonpolar and uncharged; this makes the lipid tail hydrophobic. This combination makes phospholipids fluid and amphipathic molecules. The phospholipid heads face outward, allowing them to interact with the intracellular fluid and extracellular fluid. There are multiple membrane proteins scattered throughout the cell membrane. These proteins assist with determining what substances may travel in and out of the cell. Integral proteins are embedded within the membrane; peripheral proteins are found on the inner or outer surface of the phospholipid bilayer. Channel proteins facilitate the diffusion of certain materials through the phospholipid bilayer using simple diffusion. Carrier proteins transport larger substances into and out of the cell using simple diffusion. Protein pumps transport substances into or out of the cell using active transport. Active transport requires ATP, the energy currency of the cell. Aquaporins are channels that allow the transport of water in and out of the cell via osmosis. (Engel A al et. 1994).
The cytosol is the watery-like substance found inside of the cell. It contains the organelles and provides the fluid necessary for chemical reactions. The cytoskeleton provides support and structure for the cells. It is composed of a group of fibrous proteins. The cytoskeleton is made up of microfilaments, intermediate filaments, and microtubules. The microtubules are also important for arranging the genetic material during cell division. The nucleus is the “control center” of the cell. It houses the cell’s DNA. The nucleus dictates everything the cell does and the products it makes. The endoplasmic reticulum connects to the nuclear membrane. It provides a passageway for transporting, synthesizing, and storing various materials. The endoplasmic reticulum can be either rough endoplasmic reticulum or smooth endoplasmic reticulum. The rough endoplasmic reticulum is spotted with multiple ribosomes. The main function of the rough endoplasmic reticulum is synthesizing and modifying proteins. Ribosomes are organelles that serve as the site for protein synthesis. Ribosomes can be found on the rough endoplasmic reticulum or floating in the cytosol. The smooth endoplasmic reticulum synthesizes phospholipids and steroid hormones. It also breaks down toxins and metabolizes certain carbohydrates. After proteins are synthesized, they are usually transported to the “post office” of the cell, the Golgi apparatus. The Golgi apparatus sorts, modifies, and ships off the products from the rough endoplasmic reticulum. The one side of the Golgi apparatus receives products in the form of vesicles; the other side releases the products after they are repackaged in new vesicles.
Lysosomes are the “trash cans” of the cell. (Yoshimori T 2002). Vesicles released by the Golgi apparatus, known as proto-lysosomes, mature into functional lysosomes. (Chen Y and Yu L 2017). They contain enzymes that break down and digest unnecessary or damaged cellular components. Lysosomes also break down foreign material such as bacteria. They also serve as the “self-destruct button” in the case where controlled cell death is necessary. Peroxisomes are organelles that contain enzymes. They are involved in lipid metabolism and chemical detoxification. The enzymes contained in peroxisomes transfer hydrogen atoms to oxygen. This produces hydrogen peroxide. The peroxisomes contain enzymes that convert hydrogen peroxide into water and oxygen. These byproducts are then released into the cytoplasm. This allows the peroxisomes to neutralize poisons such as alcohol. Peroxisomes monitor the reactions that neutralize free radicals. The peroxisomes act as the “sewage treatment plants” by neutralizing toxins so they don’t destroy the cells. The mitochondria are the “powerhouses” of the cell. (Magalhaes J al et. 2014). The inner membrane of the mitochondria store proteins, enzymes, and other molecules used to perform the biochemical reactions of cellular respiration. These reactions use the energy stored in nutrients to produce ATP. The mitochondria are in constant use due to cells’ constant demand for ATP. The mitochondria are also important for maintaining calcium homeostasis. (Magalhaes J al et. 2014). Research has also shown that mitochondria function as signaling organelles. (Chandel NS 2015). Mitochondria communicate with the cytosol to initiate biological events. (Chandel NS 2015).
Engel A, Walz T, and Agre P. 1994. The aquaporin family of membrane water channels. Current Opinion in Structural Biology. 4:4:545-553.
Yoshimori T. 2002. Toward and beyond lysosomes. Cell Structure and Function. 27:6:401-402.
Chen Y and Yu L. 2017. Recent progress in autophagic lysosome reformation. Traffic. 18:6:358-361.
Magalhaes J, Venditti P, Adhihetty PJ, Ramsey JJ, and Ascensao A. 2014. Mitochondria in Health and Disease. Oxidative Medicine and Cellular Longevity. 2014:814042.
Chandel NS. 2015. Evolution of Mitochondria as Signaling Organelles. Cell Metabolism. 22:2:204-206.