What is the function of the endoplasmic reticulum?
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1) The Rough (Granular) Endoplasmic Reticulum (ER) synthesizes proteins.\n\n2)  The Smooth ER synthesizes lipids, especially phospholipids and cholesterol.\n\n3) Other functions of the ER, especially the smooth ER include: \n   a) glycogen breakdown for energy\n   b) detoxification - it contains a vast number of enzymes that are capable of detoxifying substances, such as drugs, that might damage the cell.\n\nBest wishes and good luck!
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Movement of substances across the cell membrane is the function of the 3 types of diffusion.\n\n\nThe generalized cell functions include movement of substances across the cell membrane, cell division to make new cells, and protein synthesis. \n\n\nMovement of substances across the cell membrane \nThe survival of the cell depends on maintaining the difference between extracellular and intracellular material. Mechanisms of movement across the cell membrane include simple diffusion, osmosis, filtration, active transport, endocytosis, and exocytosis. \n\nSimple diffusion is the movement of particles (solutes) from a region of higher solute concentration to a region of lower solute concentration. Osmosis is the diffusion of solvent or water molecules through a selectively permeable membrane. Filtration utilizes pressure to push substances through a membrane. Active transport moves substances against a concentration gradient from a region of lower concentration to a region of higher concentration. It requires a carrier molecule and uses energy. Endocytosis refers to the formation of vesicles to transfer particles and droplets from outside to inside the cell. Secretory vesicles are moved from the inside to the outside of the cell by exocytosis.
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reticulum, that's how its spelled...and it's the network of transportation through a cell
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When a protein is synthesized at a ribosome, it travels to the endoplasmic reticulum to get modified and packaged. Then it travels to the Golgi Apparatus, which gets the protein ready for leaving the cell.\n\nSo both the ER and the Golgi Apparatus package the protein to help it leave the cell.
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a) do your own homework - its not that difficult to find it out yourself.\n\nThe endoplastic reticulum streches throughout the cell creating a cytoskeleton and providing transport for things that need moving around the cell.  Ribosomes are one of the things that that will transport around - endoplastic reticulum with ribosomes attached is known as rough endoplastic reticulum.  So the answer should be obvious now.
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Function\nLike the ovaries (to which they are homologous), testicles are components of both the reproductive system (being gonads) and the endocrine system (being endocrine glands). The respective functions of the testicles are:\n\nproducing sperm (spermatozoa) \nproducing male sex hormones, of which testosterone is the best-known \nBoth functions of the testicle, sperm-forming and endocrine, are under control of gonadotropic hormones produced by the anterior pituitary:\n\nluteinizing hormone (LH) \nfollicle-stimulating hormone (FSH) \nStructure\nUnder a tough fibrous shell, the tunica albuginea, the testis contains very fine coiled tubes called the seminiferous tubules. The tubes are lined with a layer of cells that, from puberty into old-age, produce sperm cells. The sperm travel from the seminiferous tubules to the rete testis, the efferent ducts, and then to the epididymis where newly-created sperm cells mature (see spermatogenesis). The sperm move into the vas deferens (also called the ductus deferens), which opens into the urethra. Upon any sufficient sexual arousal, the sperm cells move through the ejaculatory duct and into the prostatic urethra, where the prostate, through muscular contractions, ejaculates the sperm, mixed with other fluids, out through the penis.\n\nThe genital anatomy described here, along with the neuroanatomy and hormonal systems that enable it to perform ejaculation, have as primary evolutionary functions the impregnation of a fertile female of the same species (or a sufficiently close one), via sexual intercourse with her.\n\n \nTransverse section through the left side of the scrotum and the left testis. The sac of the tunica vaginalis is represented in a distended condition.Between the seminiferous tubules are special cells called interstitial cells (Leydig cells) where testosterone and other androgens are formed.\nin the absence of these testis I doubt whether that person could have any capacity for reproduction
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A membrane-bound organelle in the cytoplasm of most cells containing various hydrolytic enzymes that function in intracellular digestion\nBasically it helps brake down complex molecules into smaller, simpler ones
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The answer is D.  Protein synthesis takes place along the endoplasmic reticulum.  The synthesized proteins move to the golgi apparatus, and are then packaged in vesicles to be transported out of the cell (those that are destined to leave the cell).  In your example, the radiolabeled proteins are destined to leave the cell, so they would need to go to the cell membrane in order to exit the cell.  Going to the nucleus would be going the wrong direction.\n\nhttp://users.rcn.com/jkimball.ma.ultranet/BiologyPages/G/Golgi.html
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The lysosomes in the cell are the cleaners of the cell. Think of lysol when you think of lysosomes. Their functions include digesting bacteria, viruses, and toxins, breaking down worn out or nonfunctional organelles. Perioxisomes are the only sites in the cell where digestion can take place safely. They also breakdown down free radicals which have entered the cell which can be hazardous to the cell.\nLysosomes and perioxsomes exist in the cytoplasm of the cell. As far as ingesting injured cells.. I'm not sure.
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First, the cell wall's function is to protect the plant cell.\nCell membrane - protects inner components of the cell from the outer environment. The rest are describe in the following website which you can go to.
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In cell biology, a vesicle is a relatively small and enclosed compartment, separated from the cytosol by at least one lipid bilayer. If they have only one lipid bilayer, they are called unilamellar vesicles; otherwise they are called multilamellar. Vesicles store, transport, or digest cellular products and wastes.\n\nThis biomembrane enclosing the vesicle is the same as that of the outer cellular membrane. Then, because of the separation, the intravesicular environment can be made to be different from the cytosolic environment. Vesicles are a basic tool of the cell for organizing metabolism, transport, enzyme storage, as well as being chemical reaction chambers. Many vesicles are made in the Golgi apparatus, but also in the endoplasmic reticulum, or are made from parts of the plasma membrane.\n\nMore at http://en.wikipedia.org/wiki/Vesicle_%28biology%29
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DNA goes to mRNA\n\nthe mRNA has a signal sequence on the 5' end which directs it to the Ribosome and indicates whether it will be inserted into the Endoplasmic Reticulum(ER) while it is being translated.  In this case it is inserted into the ER.  As it is inserted it is folded into it's 3-D conformation.  Pending on whether parts are inserted into the membrane of the ER or not it will be determined if this Plasma Membrane(PM) protein is secreted or is stuck to the membrane.  After this you get the addition of the "glyco" part of the protein through numerous transferases and other molecules inside the ER.  This only happens inside the ER, as to why the former steps were necessary.  Then the protein is transfered via a vesicle to the Golgi Apparatus where further post-translational modifications take place.  At this point the protein is ready to go to the plasma membrane as a glycoprotein.  The protein needs no signal to get there however as the pathway from the Golgi to the PM is the "default" pathway and any unmarked(so to say) vesicle will find it's way to the Plasma Membrane.  And that's that.
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It is semi-permeable and controls what substances enter and leave the cell. It allows certain substances such as amino acids, glucose, mineral salts, water etc to enter the cell and also allows other substances like enzymes or waste products (carbon dioxide, urea) to leave the cell. This helps to maintain a suitable environment in the cell for it to survive and carry out its functions properly.
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The pancreas is the organ that contains the Alpha-Islet cells, also more commonly known as the Islets of Langerhans, which secrete insulin which is the enzyme responsible for lowering blood sugar, and beta-islet cells which are responsible for secreting proteins and enzymes responsible for causing the liver to convert stored reserves of glycogen in the liver into glucose to raise the blood sugar level to a normal level if the blood glucose level is below normal.
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Cell Membrane proteins are made inside the cell and inserted into invaginations of the cell membrane called Endoplasmic Reticulum.  At least that's how it works in Eukaryotes (everything from humans and plants to Amoebae).  Prokaryotes (bacteria) must do something similar, but their internal structure is different.\n\nEukaryotes have long stretches of endoplasmic reticilum inside them (but outside the nucleus).  ER is essentially the cell membrane, in long deep convoluted invaginations; it's continuous with the cell membrane but all-but pinched off at the cell surface.\n\nProteins are manufactured by ribosomes (it's a complicated mechanism, but involves the ribosomes anyway) which read the information of mRNA to string amino acids together to make protein.  If the nascent protein chain has the right sequences, its inserted into the ER membrane as it's growing.  As it grows, it pokes through the ER  and out the other side: the "head" of the protein sticks out, while the "tail" is still growing on the inside of the cell.  If the protein has a particular control sequence, called a "stop transfer" sequence, the mechanisms pushing it through the ER stop, and it remains embedded in the ER membrane.  If it doesn't have this sequence, it gets pushed right on through.\n\nWhen the protein is finished, a small pocket of the ER membrane pinches off to form a bubble or "vessicle" inside the cell.  The vessicle membrane will have the new protein embedded in it, with the head of the protein inside the vessicle and the tail sticking out.  If the protein was pushed all the way through, it will be completely inside the vessicle.\n\nThe vessicle is moved to the cell surface by microfibers (a kind of protein called actin that forms fibers that can slide over each other.  It's also found in muscle).  The vessicle fuses with the cell surface and opens up; the "inside" of the vessicle is now the outside of the cell.  The head of the protein, that was on the inside of the vessicle, is now on the outside of the cell, and the tail of the protein is still on the inside, and the cell membrane protein is ready to go.\n\nIf the protein went all the way through the ER, and wound up completely inside the vessicle, then it is secreted (released from, as in a secretion) from the cell when the vessicle fuses with the cell membrane.  You can turn a cell membrane protein into a secretatory protein by removing the "stop transfer" sequence of amino acids from the protein.  This is believed to happen sometimes, for example, when an antibody molecule (a protein) that is embedded in the cell membrane triggers the cell to begin to secrete the same antibody molecule into the blood stream: if something binds to the embedded antibody, the cell begins to manufacture the same molecule but without the stop-transfer sequence, so the cell now secretes antibodies.
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The main functions of the nucleus are providing a compartment separated from the rest of the cell and controlling transcription.
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Some of the functions of the primary wall of a plant cell:\n\n    * Structural and mechanical support.\n    * maintain and determine cell shape.\n    * resist internal pressure of cell.\n    * control rate and direction of growth.\n    * ultimately responsible for plant architecture and form.\n    * regulate diffusion of material \n    * carbohydrate storage - walls of seeds may be metabolized.\n    * protect against pathogens, dehydration, and other environmental factors.\n    * cell-cell interactions.