All living things are made of calls, also these cells can be dividedinto two groups: PROKARYOTIC AND EUKARYOTIC. Humans and all multicellularorganisms are made of a type of cell called EUKARYOTIC cells. What makes a cell eukaryotic, is usuallyeukaryotic cells are much larger than prokaryotes, and they’re also eukaryoticcells also found in multicellular organisms, although there are single cellulareukaryotes such as certain protests. The most important thing that eukaryoticcells possess that prokaryotic don’t is the idea of compartmentalization, thismean that the cell is divided into different compartments, whereas prokaryoticcells doesn’t appear to have many different compartments. The reason whyeukaryotic cell has lots of different compartments within it, is because thecompartmentalization of the eukaryotic cell has different compartments allowseach different compartment to have a different function. This is important inthe complex needs of cells.
The name for these compartments in the eukaryoticcell is organelles. Just like your body has different organs that havedifferent functions, your heart pumps blood, your lungs take in oxygen,different organelles in the cell have different functions. These organelles areseparated from other parts of the cell by membranes, and the name “eukaryotic”comes from one of these organelles (compartmentalization and Organelles-“Membrane Bound”). When scientists originally looked at the eukaryotic cells,they saw a well-formed circular object in the centre that looked kind of like anut. And so, they called these cells “eukaryotes” because they had awell-formed nut in the centre of the cell. This nut is what we now know as thenucleus. The nucleus is a circular membrane-bound organelle that contains allthe genetic material in the cell, so all your chromosomes are inside thenucleus. This separates them from the outside of the of the cell.
The nucleusis the defining organelle of eukaryotic cells. In contrast, prokaryotic cellshave their genetic material as well as everything else in the cell just kind offloating around all in one big space.And so, prokaryotes, to divide and become new cells, all they must do ismake two copies of everything, and then split down the middle in a processcalled “Binary fission”.
But in eukaryotes we can see that there because thecell has these different compartments or organelles, there is a more complexway to divide into a new cell, and the process that eukaryotic cells use todivide is called “mitosis”. So, these are the defining characteristics/structure of eukaryotic cellsthat sets them apart from prokaryotic cells, other important organelle within eukaryoticcells. Going back to nucleus I kind of think of as the control centre of thecell because that’s where all the DNA is, and where DNA is transcribed intomRNA. Probably the next most important organelle in the body are calledmitochondria.
Mitochondria is the cell’s power plant because mitochondria arethe site of cellular respiration where glucose is converted into ATP, toprovide the energy for everywhere else in the cell. The next organelle iscalled the Endoplasmic reticulum; this is primarily the side of proteinsynthesis. mRNA, which is transcribed from DNA in the nucleus, translated atthe endoplasmic reticulum.
So, I think of endoplasmic reticulum as the factoryof the cell where proteins are produced, after these proteins are produced theysend to another organelle that has kind of a lot of folded membrane structure,but it’s not a continuous compartment like endoplasmic reticulum. And thisorganelle is called the “Golgi apparatus”. The Golgi apparatus is kind of likethe mail room of the cell, so proteins that are produced in the endoplasmicreticulum are sent to the Golgi apparatus, and the Golgi apparatus can sendthose proteins to other parts of the cell depending on where that protein needsto go. So, if the protein needs to been secreted by the cell the Golgiapparatus sends it to the outer membrane of the cell and releases it. The lasttwo organelles to mention are the “Lysosome and Peroxisome”, cells can havemultiple ones of each of these but I mentioned them together because they bothhave a similar structure.
They’re kind of a spherical organelle enclosed by asingle plasma membrane, and the environment inside the lysosomes and theperoxisome is very different from the environment outside in the cell’s cytosolso the lysosomes and peroxisomes are kind like recycling centres in the cell,that because when cellular components are no longer functional and need to be brokendown, they’re trafficked to the lysosome where they are broken down into their morebasic components that can be reused to rebuild new proteins or other macromolecules.The peroxisome has a similar function to the lysosome, but it’s a little bitdifferent because in the peroxisome is the site where reactive oxygen specieslike peroxides are reduced into nontoxic forms. Prokaryotic cells don’t have a lot of structures in them. If you lookdown to the diagram,Here we have a few structures that stand out there’s the DNA that’s kindof here in the in the middle of the cell, there’s also some ribosomes scatteredthroughout their cytoplasm, a long flagellum, a plasma membrane that’s aboutall there is to it.
They’re very simple cells, these prokaryotic cells also theway they divide is very simple. They have one circular chromosome, thatcircular chromosome will split and then the cell membrane divides in two newcells that full process is called “Binary Fission”. The few structures that arefound in these prokaryotic cells that I’m going to talk about are cytoplasm andgranules. Cytoplasm is also known as “Protoplasm” is basically a matrix whichmeans like a surrounding substance that has these different things in it, soit’s got water, enzymes, nutrients waste and gases. All sorts of tons of stufffor the cell but also contains those cell structures because it has a cellstructures that’s how the cell grows, how it makes energy, how it replicates soall those functions the cell does is going to be in the cytoplasm. The mostimportant thing is that, this matrix that contains all these differentmolecules as well as the cell structures themselves. The second structure is Granules;Granules is to prokaryotic cells like bacteria, bacteria are example ofprokaryotic cell. That’s how the bacteria going to store their nutrients sothat’s kind the important part of what granules do.
Bacteria don’t have a lotof other structures in them so they need a way to keep nutrients handy andavailable so they use granules.The third structure is Ribosomes;The ribosomes can be found in the side of cytoplasm or attached to theplasma membrane.Ribosomes in “Prokaryotic cells” and “Eukaryotic cells” they makeprotein, as we know protein is the structure compartment of things that are incells so protein help to build stuff. The protein needed to help build thecell, bacterial cells can contain thousands and thousands of ribosomes. The Cytoskeleton is like a skeleton for thecell so it helps to scaffold or hold the shape of the cell itself. The nextstructure found in prokaryotic cells are bacteria is the plasma membrane. Theplasma membrane acts as a barrier to separate the cell from its environment.
Prokaryoticcells like bacteria so they have a cell wall made of peptidoglycan what does isit gives real rigid support to the cell itself, it helps and support thestructure the cell but it does allow solute so particles to move in and out ofcell. Endospores are like little capsules when the bacteria go dormant stopsgrowing, stops reproducing and stops the most civics function but then can kindof reawaken after a time. The flagella allow for movement not all bacteria haveespecially those that lives in water aquatic environments flagella helps themto swim around, another type of appendage is the pili they are tubes that comeout of the bacteria that are shorter than flagella. They can also be used formovement like grappling hooks and can be used for conjugation to transferplasmids so basically two bacteria can hook up and exchange DNA with eachother, and the pili is this tube that allows them to transfer DNA from onebacteria to another.Prokaryotic doesn’t have nucleus, no organelle and membrane bound buteukaryotes has the nucleus also the organelles, both cells Eukaryotic cells andProkaryotic cell both have ribosomes, DNA, Cytoplasm, Cell membrane and somehave flagella.There is big different size in these cells, theEukaryotic cell is bigger than the Prokaryotic cells.
The size of Prokaryoticcell is roughly around 0.1to 5.0 ?m in diameter andEukaryotic cells which are bigger than prokaryotic cells are roughly around 10to 100 ?m. The small size of prokaryotes allows ions and organic moleculesthat enter them to quickly diffuse to other parts of the cell.