Chapter 10 The Structure and Function of DNA  In DNA, the “backbone” of the double helix is formed by bonds between the deoxyribose sugar of one nucleotide and the phosphate group of the next.  DNA bases are adenine, cytosine, guanine, and thymine.  According to complementary base-pairing rules, for every G in the DNA double helix, there must be a C.  Using the DNA sequence, TACGGTACCATTGCGCAA, determine which of the following choices is the complementary RNA molecule. AUGCCAUGGUAACGCGUU  A sequence in DNA specifies the amino acid sequence of a protein. Figure 1 DNA Structure  A DNA molecule is a polymer made of nucleotides.  Mutations are changes in the sequence of DNA. Figure 2 DNA Replication  Successful DNA replication results in two double helix molecules, each half parental DNA and half newly synthesized DNA.  Inserting or deleting a nucleotide in a protein-coding sequence produces what type of mutation? Frameshift  Which of the following features of DNA molecules contains the actual code for building proteins? Sequences of bases.  In eukaryotic cells, transcription occurs in the nucleus while translation occurs in the cytoplasm. Figure 3 Protein Synthesis Transcription Figure 4 Protein Synthesis RNA Processing  RNA polymerase synthesizes messenger RNAs (mRNAs).  How do transfer RNAs (tRNAs) bring the correct amino acid to the growing polypeptide? By complementary base pairing between the tRNA anticodon and the messenger (mRNA) codon.  There are 3 messenger RNA (mRNA) bases that make up a codon.  Which role do ribosomes play in protein synthesis? Ribosomes provide a site for tRNA to bind to mRNA. Figure 5 Protein Synthesis Translation  The end of translation occurs when a stop codon in the mRNA is reached.  During translation, the start codon codes for “start” and the amino acid methionine. Figure 6 Summary of Transcription and Translation  Ribosomes are made up of protein and RNA.  A gene is the information for making a specific amino acid sequence.  Are viruses alive? No, their lack of cell and replicative ability prevents them from being classified as alive. Figure 7 Protein Production Figure 8 Transcription from DNA to RNA