Cytoplasm - Definition and Function

Cytoplasm - Definition and Function Cytoplasm consists of all of the contents outside of the nucleus and enclosed within the cell membrane of a cell. It is clear in color and has a gel-like appearance. Cytoplasm is composed mainly of water but also contains enzymes, salts, organelles, and various organic molecules. Cytoplasm Functions The cytoplasm functions to support and suspend organelles and cellular molecules. Many cellular processes also occur in the cytoplasm. Some of these processes include protein synthesis, the first stage of cellular respiration (known as glycolysis), mitosis, and meiosis. In addition, the cytoplasm helps to move materials, such as hormones, around the cell and also dissolves cellular waste. Divisions The cytoplasm can be divided into two primary parts: the endoplasm (endo-,-plasm) and ectoplasm (ecto-,-plasm). The endoplasm is the central area of the cytoplasm that contains the organelles. The ectoplasm is the more gel-like peripheral portion of the cytoplasm of a cell. Components Prokaryotic cells, such as bacteria and archaeans, do not have a membrane-bound nucleus. In these cells, the cytoplasm consists of all of the contents of the cell inside the plasma membrane. In eukaryotic cells, such as plant and animal cells, the cytoplasm consists of three main components. They are the cytosol, organelles, and various particles and granules called cytoplasmic inclusions. Cytosol: The cytosol is the semis of organelles include mitochondria, ribosomes, nucleus, lysosomes, chloroplasts, endoplasmic reticulum, and Golgi apparatus. Also located within the cytoplasm is the cytoskeleton, a network of fibers that help the cell maintain its shape and provide support for organelles.Cytoplasmic Inclusions: Cytoplasmic inclusions are particles that are temporarily suspended in the cytoplasm. Inclusions consist of macromolecules and granules. Three types of inclusions found in the cytoplasm are secretory inclusions, nutritive inclusions, and pigment granules. Examples of secretory inclusions are proteins, enzymes, and acids. Glycogen (glucose storage molecule) and lipids are examples of nutritive inclusions. Melanin found in skin cells is an example of a pigment granule inclusion. Cytoplasmic Streaming Cytoplasmic streaming, or cyclosis, is a process by which substances are circulated within a cell. Cytoplasmic streaming occurs in a number of cell types including plant cells, amoeba, protozoa, and fungi. Cytoplasmic movement may be influenced by several factors including the presence of certain chemicals, hormones, or changes in light or temperature. Plants employ cyclosis to shuttle chloroplasts to areas receiving the most available sunlight. Chloroplasts are the plant organelles responsible for photosynthesis and require light for the process. In protists, such as amoeba and slime molds, cytoplasmic streaming is used for locomotion. Temporary extensions of the cytoplasm known as pseudopodia are generated that are valuable for movement and capturing food. Cytoplasmic streaming is also required for cell division as the cytoplasm must be distributed among daughter cells formed in mitosis and meiosis. Cell Membrane The cell membrane or plasma membrane is the structure that keeps cytoplasm from spilling out of a cell. This membrane is composed of phospholipids, which form a lipid bilayer that separates the contents of a cell from the extracellular fluid. The lipid bilayer is semi-permeable, meaning that only certain molecules are able to diffuse across the membrane to enter or exit the cell. Extracellular fluid, proteins, lipids, and other molecules may be added to a cells cytoplasm by endocytosis. In this process, molecules and extracellular fluid are internalized as the membrane turns inward forming a vesicle. The vesicle encloses the fluid and molecules and buds off from the cell membrane forming an endosome. The endosome moves within the cell to deliver its contents to their appropriate destinations. Substances are removed from the cytoplasm by exocytosis. In this process, vesicles budding from Golgi bodies fuse with the cell membrane expelling their contents from the cell. The cell membrane also provides structural support for a cell by serving as a stable platform for the attachment of the cytoskeleton and cell wall (in plants). Sources: â€Å"Cytoplasmic inclusions.† The Free Dictionary, Farlex, medical-dictionary.thefreedictionary.com/cytoplasmic inclusions. â€Å"Ectoplasm.† The Free Dictionary, Farlex, medical-dictionary.thefreedictionary.com/ectoplasm.â€Å"Endoplasm.† The Free Dictionary, Farlex, medical-dictionary.thefreedictionary.com/endoplasm.Goldstein, Raymond E., and Jan-Willem van de Meent. â€Å"A physical perspective on cytoplasmic streaming.† Interface Focus, The Royal Society, 6 Aug. 2015, www.ncbi.nlm.nih.gov/pmc/articles/PMC4590424/.

Do Some Research on Fact-Checking

Do Some Research on Fact-Checking Do Some Research on Fact-Checking Do Some Research on Fact-Checking By Mark Nichol Do you want to be a magazine writer? I know it’s a highly competitive profession, but I’ve got two words for you (and a bonus hyphen): fact-checking. What’s that? Fact-checking is an entry-level profession in the magazine industry that can lead to staff or freelance writing opportunities. Fact-checkers are responsible for verifying every quantifiable piece of information in an article: spelling of names and entities such as companies, institutions, and organizations; names of products and services; dates of birth, incorporation, and publication; prices and profits; and more so much more. Sound tedious? It can be, but it is also excellent training for reporters and writers: not only do fact-checkers (also called research editors) vet article content, they also often help writers with background research. Once you put in a couple of years as a staff or contract fact-checker, you’ve got a leg up on many other writers when it comes to turning in meticulously researched articles not to mention getting a crash course in reporting by doing preliminary work for more experienced writers and fact-checking numerous articles. Fact-checkers are often given brief writing assignments or are even promoted to junior writing positions, but the career ladder doesn’t stop there: Onetime fact-checkers include CNN newsman Anderson Cooper, novelist Jay McInerney, and former Harper’s editor Roger Hodge. Not every magazine has staff or freelance fact-checkers by that name; sometimes, interns or junior editors fill the role as part of their job duties, or copy editors do at least rudimentary fact-checking. Other publications, with fewer resources, trust writers to get their facts straight. Most newspapers don’t have the time or the budget for this stage, though the German daily Der Spiegel is a notable exception: It employs dozens of fact-checkers. Publications began employing fact-checkers less than a hundred years ago (the New Yorker, one of the first magazines to do so, even verifies facts in the poetry it publishes), and the profession isn’t going anywhere; even with the revolution in access to information engendered by the Internet, it’s still a vital function. And thanks to online research, it’s much easier to accomplish, though it still requires rigorous attention to detail. If you’ve tried in vain to break into magazine writing, either as a staff writer or a freelancer, you might want to consider applying to become a fact-checker. You’ll be starting out on the ground floor, but that means you’ll be the foundation of a publication’s reputation for veracity, and if you have what it takes, you’ll likely be noticed and rewarded. And though you’re not guaranteed a promotion, the job is often a stepping stone to work for other publications. But don’t take my word for it: Do some fact-checking. Want to improve your English in five minutes a day? Get a subscription and start receiving our writing tips and exercises daily! Keep learning! Browse the Freelance Writing category, check our popular posts, or choose a related post below:When to Use â€Å"That,† â€Å"Which,† and â€Å"Who†15 Words for Household Rooms, and Their SynonymsEmpathic or Empathetic?