DNA and Protein Synthesis PDF

DNA Nucleic Acids  C, O, H, N & phosphorus – largest molecules in the body  Each contains a sugar, phosphate group and bases Adenine (A), Guanine (G), Cytosine (C), Thymine (T), Uracil (U) Contribute to nucleotide structure DNA (deoxyribonucleic acid)  a double stranded polymer (cha...

DNA Nucleic Acids  C, O, H, N & phosphorus – largest molecules in the body  Each contains a sugar, phosphate group and bases Adenine (A), Guanine (G), Cytosine (C), Thymine (T), Uracil (U) Contribute to nucleotide structure DNA (deoxyribonucleic acid)  a double stranded polymer (chain) of nucleotides  the nucleotides are made up of a sugar (deoxyribose), a base (adenine, thymine cytosine, guanine) and phosphate  Typically found in nucleus of cell  Structure of DNA Pg 56. DNA: coiled polymer of nucleotides (double helix) Backbone formed by alternating sugar & phosphate units ‘Rungs’ formed by binding complementary bases Always complementary Adenine bonds to Thymine Guanine bonds to Cytosine Pg 56. Structure of DNA Functions of DNA DNA forms the genes on the chromosomes Replicates before cell division to ensure genetic information is identical Provides instructions for formation of every protein in the body Determines what type of organism you’ll be & directs growth & development Nucleic Acids RNA (ribonucleic acid) a single stranded polymer of nucleotides the nucleotides are made up of a sugar (ribose), base (adenine, uracil, cytosine, guanine) and phosphate Mainly outside of the nucleus  Protein Synthesis  DNA forms blueprint for protein synthesis  Proteins are made of polypeptide chains made of amino acids  The sequence of the 4 nucleotide bases (A, G, T, C) specifies a particular amino acid  Amino acids have distinctive properties to separate them from each other  Thus, different amino acid sequences produce a wide variety of proteins with a wide variety of structures and functions Role of RNA Decoder & messenger for DNA information All types of RNA are formed from DNA mRNA: messenger RNA copies DNA template & carries information from nucleus to cytoplasm tRNA: transfer RNA, rRNA: ribosomoal RNA help to make proteins Protein Synthesis  Transcription: DNA information transferred to mRNA  mRNA detaches & leaves nucleus  Translation: the information on the mRNA is used to assemble the correct sequence of amino acids to make a protein  mRNA reaches cytoplasm, binds to ribosomes, tRNA transfers amino acids  Each specific tRNA brings specific amino acids Pg 105. DNA Replication  Consists of breaking the weak H+ bonds between the bases  This leaves single DNA strands with each base unpaired  The single strand is a template for a complimentary molecule to be built from  Unpaired bases attract free nucleotides only if that nucleotide has the right complimentary bases  DNA polymerase – most important enzyme responsible for replication  Travels along single DNA strand (template) & adds correct new strand  i.e. checks the DNA molecule to ensure all bases are actually complimentary to the template Mutation  Any inherited alteration of genetic material  Can cause disease or can be subtle  Base-pair substitution: one base pair replaces another  Frameshift mutation: involves the insertion or deletion of 1 or more base pairs of the DNA molecule  Mutagens: agents that increase the frequency of mutations i.e. chemicals and radiation  Mutations can result in huge variation in the amino acid sequence  Thus, protein (DNA) structure and function will differ to original