Diploma Biology Notes Essay Example for Free

Diploma Biology Notes Essay deoxyribonucleic dit is a huge information database that carries the complete set of instructions for making all the proteins a prison cell bequeath ever need Although there are only four different bases in DNA (A, C, G and T), the order in which the bases occur determines the information to hire a protein, just like the 26 earn of the alphabet combine to form words and sentences Compare RAT TAR ART same 3 letters completely different meanings. And with DNA GAC AGC CGA same 3 letters completely different meanings to the cell (specifies the amino acids Aspartic Acid, Serine, and Arginine)Q Review What are elements?A The DNA in each chromosome that DOES provide the instructions for a protein is called a gene. * In the 1940s, scientists proposed, fairly correctly, that each gene codes for (contains the instructions for) one protein. This is referred to as the one-gene, one-protein hypothesis. * One gene will code for perhaps two or more rel ated proteins. * Scientists realized that we had only or so 30,000 genes, coding for 100,000 different proteins rather than the 100,000 genes that had been estimated for the human genome * The basic hypothesis is until now the same, but we know a lot more details. Q If DNA is in the nucleus and proteins are synthesized in the cytoplasm, on ribosomes and in the RER, how to they bestow together? A The answer use a messenger to carry the instructions from DNA break into the cytoplasm. A nucleic acid very similar to DNA, called mribonucleic acid or messenger ribonucleic acid, is a copy of a gene, and serves this function the bridge among DNA and protein The Central DogmaDNA encodes the information to make RNA and RNA molecules function together to make proteinII. What is RNA and how is it different from DNA?Two big differences between DNA and RNA* 1. The sugar in DNA is deoxyribose in RNA it is ribose * 2. The nitrogenous base uranium (U) is employ in RNA in place of T (they are very similar bases in RNA U= A just like T = A.)III. Transcription Re-writing DNA into RNADNA has a sense strand and an antisense strand. The antisense strand is complementary to the sense strand. It is also known as the scout strand, as this is the strand, which is used for transcription making mRNA. DNA is transcribed or re-written into RNA in a very complicated process called transcription. Simply stated, during transcription, one gene (DNA) is re-written into RNA in the nucleus * A team of enzymes and proteins binds to the promoter, or starting region, of a gene. * These enzymes and proteins unzip the DNA double helix just at the region of the gene. * The enzyme RNA polymerase uses one of the DNA strands to make an RNA copy of that one gene. * This copy, which contains the instructions to make 1 protein, is called an mRNA or messenger RNA. * After the mRNA is made, it is trimmed down to a final exam size, and shipped out of the nucleus. * When the mRNA gets into the cytopla sm, it is made into protein * Complete transcription of an RNA molecule.1. The resulting RNA nucleotides are added on the 3 displace of the growing of mRNA strand. 2. RNA polymerase detaches itself and mRNA is released.3. Eukaryote pre- mRNA contains exons and introns* Introns are non-coding regions that need to be removed before interpretingThe structure of tRNA matches its functions Funtion to bring amino acids from the cytoplasm to the growing polypeptide and to bring together them in the current location. tRNA is activated by a tRNA activating enzyme. tRNA delivers amino acids to the growing polypeptide chain in translation.It picks up new amino acids when activated by a special(prenominal) tRNA activating enzyme.IV. Connection between mRNA and proteinThe order of the bases in the DNA specifies the order of bases in the mRNA, andThe order of bases in the mRNA specifies the order of amino acids in a protein. The genetic code is a triplet code (handout)1. Nucleotides on mRNA are read three at a era by the ribosome. * Every three nucleotides in an mRNA (a codon) specify the addition of one amino acid in a protein. * For example, a 600 nucleotide mRNA will code for a 200 amino acid protein. 2. The amino acids corresponding to all 64 codons have been determined. all proteins start with the initiation codon AUG (Met) * All proteins end with stop codons -either UAA, UGA, or UAG * Some codons that differ in the third nucleotide potbelly still code for the same amino acidThe genetic code chart represents the sequence on the mRNA codon. V. Translation = De-coding RNA into proteinDuring translation, the mRNA transported to the cytoplasm is de-coded or translated to produce the correct order of amino acids in a protein. Translation requires numerous enzymes. rRNA = ribosomal RNA these RNA molecules associate with other proteins to form the ribosomes. Each ribosome can accept two tRNAs at a time (carrying amino acids) and one mRNA. tRNA = transfer RNA small RNA molecules that carry a specific amino acid at one end and an anticodon region that recognizes and binds mRNA at the other end. The tRNA that binds to that mRNA codon determines what amino acid is added to a protein chain. The deuce-ace RNAs (mRNA, tRNA, and rRNA) all work together to turn the information in DNA into a 3-dimestional protein.The steps of translation1. Initiation mRNA enters the cytoplasm and becomes associated with ribosomes (rRNA + proteins). tRNAs, each carrying a specific amino acid, pair up with the mRNA polys inside the ribosomes. Base pairing (A-U, G-C) between mRNAcodons and tRNA anticodons determines the order of amino acids in a protein. 2. extension addition of amino acids one-by-oneAs the ribosome moves along the mRNA, the tRNA transfers its amino acid to the growing protein chain, producing the protein codon by codon 3. landmark when the ribosomes hit a stop codon UAA, UGA, or UAG the ribosome falls apart. The same mRNA may be used hundreds of times during translation by many ribosomes before it is broken down by the cell.