ANATOMY AND PHYSIOLOGY 1 Transcription, Translation, and Replication Jennifer Kitchen HS120-01 Unit 2 Assignment Kaplan University May 1, 2011
ANATOMY AND PHYSIOLOGY 2The Nucleic Acid Pairs There are two nucleic acids; ribonucleic acid (RNA) and deoxyribonucleic acid (DNA).They are made up of units called nucleotides, chemical building blocks, that each includes aphosphate, a five-carbon sugar, and a nitrogen base (Thibodeau & Patton, 2008).DNA ismolecule consisting of an extremely long chain of nucleotides in the form of a double helix(Nuland, 1997). This looks like a twisted ladder. DNA is found in the nucleus and is the geneticmaterial of the cell that carries the chemical “blueprint” of the body(Thibodeau & Patton,2008).The cells of the body keep this information and can copy it whenever needed. RNA is alinear moleculecomposed of a single chain of nucleotides for which synthesis DNA is thetemplate (Nuland, 1997). This means it is half of the twisted ladder. RNA is found in the in thecytoplasm and is crucial to protein synthesis(Thibodeau & Patton, 2008).DNA makes RNA andRNA, in turn, makes protein.Transcription, Translation, and DNA Replication Transcription and translation are important in the production of protein. Transcriptionoccurs when the double-stranded DNA molecules unwind and form messenger RNA (mRNA)(Thibodeau & Patton, 2008).RNA transcription happens in the nucleus of a cell and occurs whena message, for needed amino acids, is received from outside the cell. A strand of RNA isconstructed using DNA as a template(Nuland, 1997). This means the genetic information fromthe DNA is transferred to the RNA. The mRNA strand will travel to the ribosome where the
ANATOMY AND PHYSIOLOGY 3RNA sequence will be read and translated (Kwpitcairn, 2007). Translation is the synthesis ofprotein by the ribosomes in the cytoplasm of the cell (Thibodeau & Patton, 2008).A polypeptidechainis constructed after the assembling of a sequence of amino acids on a strand of RNA(Nuland, 1997). Where RNA needs DNA in order to make proteins, DNA replication is theunique ability of the DNA molecules to make copies of themselves(Thibodeau & Patton, 2008).Replication is the process that creates new DNA. The DNA strand splits and the two halvesbecome their own strands. Next a portion of DNA is transcribed onto a strand of RNA. Then theRNA nucleotides join up with the template strands of DNA(Kwpitcairn, 2007). This makes anew DNA chain and is used in the building and maintaining of the cells of the body.A Little about the Functioning of Organelles Organelles are structures inside of a cell which have specific functions. These structureshelp maintain homeostasis in a cell much as organs maintain homeostasis in the body. A few ofthe organelles are mitochondria, ribosomes, endoplasmic reticulum, and the Golgi apparatus.Some organelles, such as mitochondria, have their own genetic material separate from that foundin the nucleus of the cell.Mitochondria are the “power plants” of the cell, involved in chemicalreactions that release energy to be used by the cells for production and maintenance(Thibodeau& Patton, 2008). These reactions are caused by enzymes breaking down glucose and othernutrients and the energy is used throughout the body. This energy is what keeps the heartbeating and the nerves transmitting and receiving.Ribosomes are the “protein factories” of thecell because their function is to make enzymes and other protein compounds(Thibodeau &Patton, 2008).They are tiny dots found throughout the entire cell and may be free in the
ANATOMY AND PHYSIOLOGY 4cytoplasm or attached to the membrane of the endoplasmic reticulum.Each dot or particle ismade up of two tiny subunits which are constructed of a special RNA called ribosomal RNA(rRNA) and protein and are the site of protein synthesis. Enzymes and proteins are usedthroughout the body for many purposes, such as forming tissue and in the synthesis of hormones.Endoplasmic reticulum is networks of connecting sacs and canals within the cytoplasm of a cell,occurring either with a smooth surface (smooth endoplasmic reticulum) or studded withribosomes (rough endoplasmic reticulum). Smooth endoplasmic reticulum synthesis chemicalsto maintain the plasma membrane. Rough endoplasmic reticulum collects and transport proteinsmade by ribosomes(Thibodeau & Patton, 2008).If the ER did not perform its function, “a cellwould not be able to produce the proteins and lipids necessary for basic functions, and would die.It would be like our body losing the function of the liver” (Kitchen, 2011).Golgi apparatus can becalled the cell‟s “chemical processing and packaging center”. The primary function of the Golgiapparatus is to process and package the proteins and lipids that are synthesized by acell(Thibodeau & Patton, 2008).This organelle stores and modifies these products for specificfunctions and prepares them for transport to other parts of the cell.
ANATOMY AND PHYSIOLOGY 5ReferencesKitchen, J., (2011). Response to discussion post „Topic #3- organelles‟ by Michelle Goble.HS120-01 Anatomy and Physiology I; Kaplan University.Kwpitcairn, (2007). Replication, Transcription, and Translation. Retrieved from http://www.youtube.com/watch?v=3aVT2DTbtA8 .Nuland, S., (1997). How we live. New York; Vintage.Thibodeau, G. and Patton, K., (2008). Structure and function of the body. Missouri; Mosby Elsevier.