#cyotology

[biologynoteshp]

How does the cell works?

The cells are part of all those who are alive (I’ll make an article about viruses another time). It’s what composes us, every part of it. The organelles in it work just like as fabric, to keep it all working. The organisms can be differed by their quantity of cells, those who are unicellular (algae, bacteria, protozoan, some fungae and the archaens) and the multicellular (just like us and the plants). An important reminder, is that we have different cells in our body to perfom every function required to keep working, like the muscle ones that makes us move and those on the intestine that absorbs the nutrients. 

                                          THE EUKARYOTIC

Each of these organelles work in different ways to make the cell function well. All of them are kept in the cytoplasm, which is composed by cytosol, a viscous fluid basicly made of water, ions and also substances like carbs, enzyme, protein and salts). The amount of water on it allows substances to move and provide a better enviroment to quimical reactions, also the deslocation of the organelles.

                         The organelles and their functions

Nucleus - Keeps the DNA, controlling the hereditary traits of an organism. Works as the central control of the cell. Inside of it we have the nucleolus, this one helps on the production of RNA (a molecule that manages on the synthesis of protein). In the middle of this two, we have the chromatin, which is basically the DNA plus the histones (proteines), they contain the genetic information. And to finish, this is all enveloped by the cariotheca, which is almost the same as the plasma membrane, it also has some holes on it to control the “in and out” of substances on the cytoplasm.

Plasma membrane - It envelop the cell and controll what comes in and out = It has a function of selective permeability.  Through the Fluid Mosaic Model, it shows that the plasma membrane is formed by a phospholipid bilayer, the one that’s given the power of the selective permeability, and those proteins (whose keep moving thanks to the fluid e oil consistency of the plasma) that got a lot of functions, mostly the transportation of substances in and out of the cell.

Mitochondrion - They’re responsible for the cellular respiration, and because of this process they create a lot of ATP (provides energy to many process in the cells). There’s a theory that the mitochondrion was initially a bacteria that was engulfed through phagocytosis creating the organalle on the eukaryotic cell.

Ribossomes - They fabricate protein by using their RNA and amino acids (molecules connected by peptide-bonds (CHONPS)). It can be shown free on the hyaloplasm or attached to the endoplasmatic reticulum (forming the rough one).

Lysosome - It digestes some particles phagocyted by certain cells, such as lipids, carbs, protein and nucleic acid (DNA or RNA). It’s known that they come from the Golgy body, and their digestive substances have been formed in the Rough endoplasmatic reticulum. They also destroy the non-utilitarian cell matter. Here’s an example of how this works: In the white blood cells, whenever there’s an invasion of microrganisms, the cell emits the pseudopods (again, thanks to the cytoplasm whom gets to be deformed because of their consistency) and phagocytes the bacteria. Then the lysosomes comes and merge with this food vacuole, liberating their enzyme (proteins “ that act as biological catalysts “), this fusion forms the digestive vacuole (secundary lysosome), with this, it finally happens the klasmakytos, when the cell eliminates the particles they don’t use. 

Cytoskeleton - It’s the protein filaments on the cell, a “dynamic network”. They’re important to keep the cell steady, since we don’t have a cellulosic wall like the plants do. By the way, the pseudopods can only be formed because of the actin filaments of the cytoskeleton. It’s also used to deslocate the substances through the microtubules (a thicker filament).

Endoplasmatic reticulum - They may present changes in their shape (on the cells of a plant the endoplasmatic reticulum coincide with the vacuole). Their substances circulate through it and it may accumulate in one local. The smooth one produces lipids that composes the plasma membrane, some hormones, osmotic regulation (takes substances out of the hyaloplasm, changing the internal concentration in the cell, favoring the osmosis), like the vacuole, it stores substances. Also, it transforms toxic substances (ex: meds, alcohol) in non-toxic. Usually, people who abuses of this toxic things have a bigger reticulum than the others. The rough one got a bunch of ribossomes attached to their membranes, that makes the ER isolate and transportate the proteins that were built inside it.

Golgi body - The main function of this organelle is to modify the lipids and proteins that comes from the ER. The protein that comes from the rough ER are transferred to the Golgi body, then they’re identified or transformed. They can be inside the cells, just like the lysosome or turn into a secretion vesicle and then they are liberate as digestive enzymes.

Peroxisome - Capacity of producing hydrogen peroxity, they’re capable of neutralizing the effects of  O2.

THE PROKARYOTE CELL is the cell that makes a bacteria, archea and cyanobacteria. Although we are made of eukaryotic cells, we have some prokaryotic ones inside of us (meaning those living things said before). Just like the other type of cell, they have cytoplasm, plasma membrane, ribosomes and DNA. They lack a nucleus and the other organelles, so their DNA is found in the nucleoid. Besides the plasma membrane, there’s the cell wall to keep them in shape, and many  bacterias also have the capsule that “helps ‘em attach surfaces in the enviroment”. The fimbriea is made to connect to the mucosas of the organism, the sexual fimbriea serves for attaching the bacterias to exchange DNA and is also known as the Pilus/pili (another hair-like). Now, the primary function of the flagellum is moving the cell (as we can see like in the sperm cell). The plasmid are DNA molecules that can be shared through bacteria to bacteria, carrying around the genetic material and maybe new genes. That’s how they get more resistent.