D.+Cell+Structure

==It's amazing to think that the function of the body boils down to a microscopic cell, or the basic unit of life. There are numerous functions that the cell completes throughout the entire body. Inside the cell are many parts, or organelles, that have their own responsibilities in order for the cell to complete its overall job. Whether the organelles are for energy, movement or cleaning house, these tiny parts complete complex tasks. Inside the middle of the cell is the nucleus which holds the DNA for that cell. Cells are constantly dividing and reproducing everyday, and they do that using DNA and RNA. There are different phases which happen during cell multiplication. From the day of conception, our entire body is made up of microscopic cells. ==

==There are many parts that make up a cell. Each part has to do their job in order for the cell to complete the task needed. The outermost part of the cell is called the cell membrane which is made of two layers of phospholipids and also contains proteins. Shape and the transfer of materials in and out of the cell is the main function of the cell membrane. In between the nucleus and the cell membrane is a jello like substance, called cytoplasm. All sorts of chemical reactions occur in the cytoplasm. Lysosome sacs act like the digestive organelle, breaking down materials in the cell. The cell needs energy from somewhere and that comes from mitochondria, which creates it as well. The folds, or cristae, in the mitochondria create more space within the organelle for work to be done. Peroxisomes contain certain enzymes that degrade harmful substances, and transform hydrogen into oxygen which then creates hydrogen peroxide. Proteins are made in ribosomes which have two subunits. There are two parts to the endoplasmic reticulum, rough and smooth. The rough endoplasmic reticulum contains ribosomes, and the smooth endoplasmic reticulum is the sight for a few different chemical reactions. Inside the nucleus, which is usually in the middle of the cell, we find the genetic material, or DNA. The nucleus is surrounded by a nuclear envelope to protect the nucleus. Centrioles aid spindle fibers during mitosis. Chromatin are strands that hold the genetic code. Hair like structures on the outside of the cell help move substances along. There are so many parts which compose a cell, and each one has its own responsibilities. For example, the cell and all its parts can be compared to a car. If the motor in the car isn't working correctly, the car won't run. All the parts need to work together and complete their tasks correctly in order for success. ==

==Each cell contains some sort of genetic material. Cells needs to reproduce or multiply to keep creating more new cells. Inside the cell the genetic material DNA needs to replicate or create new DNA in order for cells to keep generating. Proteins that make up the DNA need to be translated into different proteins and made into one single strand of RNA, called genetic transcription. There are four types of RNA. Precursor messanger RNA is already altered inside the nucleus to make messenger RNA that contains the protein code for synthesis. The messenger RNA contains a genetic material that is decoded by transfer RNA. Ribosomal RNA then forms part of the organelle ribosomes. RNA is only single stranded, and is needed to create new DNA. An enzyme called RNA polymerase helps to unwind the double helix DNA so that the genetic code is exposed. After the DNA is separated, RNA then comes along and matches it's nucleotides to the nucleotides on the DNA strand. Once the RNA receives the genetic code, it then leaves the nucleus, as messenger RNA to go to a ribosome. Inside the ribosome the RNA strand then matches up with amino acids to create another strand to make specific protein. The protein then leaves the ribosome and is folded to make the protein it will become. The protein then leaves and goes to the sight where it is needed. This process can be complicated, because it is so complex. But cells are constantly multiplying and this complicated process helps to reach that goal. Because this process is so unique, the video below should help clarify what is actually happening. ==

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==The basic unit of life, this tiny microscopic cell, needs to constantly be dividing. This dividing process is called mitosis. Mitosis comes in four phases: prophase, metaphase, anaphase, and telophase. Chromosomes inside the cell which hold the genetic material are the main component in mitosis. The first phase, prophase, is when the chromosomes are easily visible under a microscope. The chromosomes kind of look like two letters v, with the bottom points together and a centromere at the bottom tip of the v's holding both of them together. Spindle fibers are created and outside the nucleus are going to aid in the process of mitosis. The part that holds both sides of the chromosome together starts to split and move towards the opposite sides of the nucleus. The nuclear envelope starts to erase slowly. The second phase, metaphase is when there is no longer a nucleus and the chromosomes line up in the middle of the cell. The centromere, the center of the chromosomes, is now attached at the spindle fibers. During metaphase, the cell starts to get longer and looks more like an oval. Anaphase is the third phase when the centromeres pull apart and each one of the v's move to opposite ends of the cell. The cell's shape resembles an oval in anaphase. During the last phase of mitosis, telophase, the chromosomes become less visible. A new nuclear membrane forms and the nucleolus starts to form. The cell now is starting to pinch in the middle, which is called furrowing. Once the cell pinches off totally, two new daughter cells which share the same genetic material are formed. Mitosis is a constant process of multiplication. ==

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== ==Meiosis is a process that kind of resembles mitosis, but in the end, the genetic material is different. DNA is being replicated, and this is how humans are created. Meiosis only occurs in the gonads, which are testes in males, and ovaries in females. In the beginning each cell contains 23 chromosomes. They replicate, and now there are two chromatids instead of one like in mitosis. The identical chromosomes in the beginner cell are called homologeous chromosomes — one pair is from the mother and the other from the father. During the first phase of meiosis called prophase 1, the chromosomes are visible and pair up. In the second phase, called metaphase 1, the chromosomes line up in the middle of the cell, or the equator. Spindle fibers are still present on the ouside of the nucleus just like in mitosis. Anaphase 1 is the next process in which the homologous chromosomes separate so there is only one pair of of genetic material on each side of the cell then they move towards opposite sides of the cell. Just like in mitosis, in telophase 1 the cell pinches off to create two new daughter cells. Each one of these daughter cells has different genetic material, not the same like in mitosis. Meiosis keeps going with divisions a second time. All of the phases are completed again, just like the first set of divisions. At the end of meiosis then there are four new daughter cells that all contain different genetic material. This process occurs only in the testes and ovaries. Once all four daughter cells are made, three of them will suffice and one of those cells will become either an ova or a sperm cell. When the sperm cell and the egg cell are combined, that is how a human is made. The video below shows the process of meiosis so the visual picture makes it easier to understand. == media type="youtube" key="uh7c8YbYGqo" height="390" width="480" align="center"

==**Cells are always releasing and bringing in materials. Diffusion is when molecules spread out to decrease the difference in the concentration gradient. When the membrane easily allows substances in and out, and the gradients are different the physical motion of the molecules in and out if called net diffusion. The net diffusion of water is called osmosis, but there are two factors that must be in place in order for osmosis to occur. First, the membrane must be selectively permeable, which means that water can go through the membrane easier than the other product in the solution. Second, there must be a difference of concentrations from inside the cell to outside the cell. When materials are brought into the cell it can be called endocytosis; exocytosis is when materials are pushed out of the cell. Substances need to be going in and out of the cell all the time, no matter what kind of transportation they use. Homeostasis of the cell must be kept constant **== media type="youtube" key="AYNwynwaALo" height="390" width="480" align="center"

==**In the healthcare field, every person or thing a nurse sees has cells and DNA. The cell is the basic unit of life, and life is what I would deal with on a daily basis. The way I was created was through meiosis, which was discussed previously. Whether I choose to work in a clinic, hospital, or somewhere else, being educated on the way cells work is essential. The way genes multiply and regenerate is uncontrollable. Sometimes DNA doesn't always turn out right, and that's when mutations happen. A familiar genetic mutation is Down's Syndrome. If I was seeing a patient who had Down's Syndrome, or who was being diagnosed with Down's Syndrome, I would want to know why it happened or how to deal with it. The family of someone just being diagnosed with Down's Syndrome would want to know why, and if I can't explain it, I am not doing a sufficient job as a nurse. These topics may be complicated and complex, but there is no reason why I don't need to learn and then understand them. **== ==**﻿The human body is definitely complex. All of the tissues, organ systems, and organs need to start being made somewhere. Some bodies are really big and some humans are really small. No matter what size human you are, everyone is made up of the same substances. Cells are very small and can only be seen through a microscope. These tiny cells are the basic structure and function of the human body. The structure of the human body, whether it be skin, bones, or etc., are all made of cells. Bones are made of osteoctyes, which are bone cells, and skin is made from epithelial cells. All these cells come together to make up the structure of the body. As we know, some parts of the structure are really hard, and some are super soft. The body still needs to continously function in order for homeostasis to be maintained. Organ systems can be very large, and the organs that make those systems up can vary in size. Organs are also made up from cells. A whole bunch of cells come together to make these organs. The organ cells are constantly working together, and with other organ cells, keep up their responsibility to the body. Cells communicate in many ways. They can be really close together, and communicate through direct contact, or through apart from each other a short range. If the cells are a long ways apart from each other they deliver messages through hormones. Electrical or chemical impulses through neurons and the use of muscle cells are another example of the way cells communicate. There are two kinds of transport that the cells have with their communication. Passive transport does not require energy, and concentrations move from higher to lower concentrations. Active transport, on the other hand, does require energy, called adenosine triphosphate, or ATP. Because active transport is moving concentrations from a low to high concentrations, it requires energy. An example of passive transport would be if the fluid outside the cell was at 40% and the fluid inside the cell was at 60%, the fluid inside the cell would simply diffuse to the outside of the cell so the concentration of the fluid would be 50%/50%. Passive transport is like a ball rolling downhill. Active transport requires energy because the concentration outside the cell is greater then the concentration inside the cell. For example, if the fluid outside the cell was 60% and the fluid inside the cell was 40%, the cell uses ATP to pull the fluid to equal 50%/50%. Pushing a stroller uphill is another example of active transport. Cells are constantly bringing in molecules and releasing molecules. The organelles inside the cell need nutrients so the cell brings them in, and when there is waste or byproduct, the cell pushes them out. The cell membrane allows this transport of molecules in and out of the cell. In order for us to to stay alive these tiny little complex cells need to keep doing their job for a lifetime. This video helps to explain the transportation better. **== == media type="youtube" key="1ZFqOvxXg9M" height="390" width="480" align="center"

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