DNA-RNA-Protein - DNA -> RNA -> Protein 1. Develop an...

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DNA -> RNA -> Protein 1. Develop an explanation of why mRNA synthesis is called transcription. Messenger RNA is RNA that carries information from DNA to the ribosome sites of protein synthesis in the cell. Once mRNA has been transcribed from DNA, it is exported from the nucleus into the cytoplasm, where it is bound to ribosomes and translated into protein. Transcription is the process through which a DNA sequence is enzymatically copied by an RNA polymerase to produce a complementary RNA. In the case of protein- encoding DNA, transcription is the beginning of the process that ultimately leads to the translation of the genetic code (via mRNA) into a functional peptide or protein. 2. Develop an explanation of why protein synthesis is called translation. During translation, mRNA is transcribed from DNA and decoded by specialized cellular structures called ribosomes to make proteins. Protein biosynthesis is divided into initiation, elongation and termination phases. The ribosome has sites, which allow another specialized RNA molecule, known as tRNA, to bind to the mRNA. Binding of the correct tRNA to the mRNA on the ribosome is accomplished by an anticodon that is part of the tRNA. Thus, the correct tRNA, chemically linked to a specific amino acid, is directed to the ribosome to be added to a growing polypeptide. As the ribosome travels down the mRNA one codon at a time, another tRNA is attached to the mRNA at one of the ribosome sites. The first tRNA is released, but the amino acid that is attached to the first tRNA is now moved to the second tRNA, and binds to its amino acid. This translocation continues on, and a long chain of amino acid (protein), is formed. When the entire unit reaches the end codon on the mRNA, it falls apart and a newly formed protein is released. This is termination. 3. Why is the inheritance of mitochondrial genes non-mendalian? The mitochondrial genome is the genetic material of the mitochondria. The mitochondria are organelles that reproduce themselves semi-autonomously when the eukaryotic cells that they occupy divide. The genetic material forming the mitochondrial genome is similar in structure to that of the prokaryotic genetic material. It is formed of a single circular DNA molecule. Mitochondria are thought to have arisen from intracellular bacterial symbiotes; this is called the endosymbiotic theory. The mitochondria of a sexually-reproducing animal comes only from the mother's side. The mitochondrial DNA
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This note was uploaded on 03/30/2008 for the course BIO 200 taught by Professor Depar during the Fall '06 term at Dubuque.

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DNA-RNA-Protein - DNA -> RNA -> Protein 1. Develop an...

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