12.3 DNA, RNA, and Protein Molecular Genetics Central Dogma  RNA  Contains the sugar ribose and the base uracil  Usually is single stranded Chapter 12

Molecular Genetics Messenger RNA (mRNA)  Long strands of RNA nucleotides that are formed complementary to one strand of DNA Ribosomal RNA (rRNA)  Associates with proteins to form ribosomes in the cytoplasm Transfer RNA (tRNA)  Smaller segments of RNA nucleotides that transport amino acids to the ribosome 12.3 DNA, RNA, and Protein Chapter 12

Molecular Genetics 12.3 DNA, RNA, and Protein Chapter 12

Molecular Genetics 12.3 DNA, RNA, and Protein Chapter 12 hill.com/sites/ /student_view0/unit3/chapter12/concepts_in_ motion.html# Copy and paste the link below into a web browser for practice with identifying the three types of RNA: (Click on the link under Interactive Tables called Comparison of Three Types of RNA)

Molecular Genetics Chapter DNA, RNA, and Protein Stenography

Molecular Genetics Chapter DNA, RNA, and Protein Stenography – an example of transcription and translation

 Translation occurs in the cytoplasm. Molecular Genetics Transcription and Translation  Transcription occurs in the nucleus DNA, RNA, and Protein Chapter 12

Molecular Genetics Transcription and Translation 12.3 DNA, RNA, and Protein Chapter 12 See video in your iPad textbook in Section 3 on Transcription and Translation. (Figure 20

 DNA is unzipped in the nucleus and RNA polymerase binds to a specific section where an mRNA will be synthesized. Molecular Genetics Transcription  Through transcription, the DNA code is transferred to mRNA in the nucleus DNA, RNA, and Protein Chapter 12

Molecular Genetics Chapter 12 Click me! 12.3 DNA, RNA, and Protein Click on the link below into a web browser to see a video on transcription:

Molecular Genetics RNA Processing  The code on the DNA is interrupted periodically by sequences that are not in the final mRNA.  Intervening sequences are called introns.  Remaining pieces of DNA that serve as the coding sequences are called exons DNA, RNA, and Protein Chapter 12

Molecular Genetics The Code  Experiments during the 1960s demonstrated that the DNA code was a three-base code.  The three-base code in DNA or mRNA is called a codon.  Start and stop codons 12.3 DNA, RNA, and Protein Chapter 12

Molecular Genetics Translation  In translation, tRNA molecules act as the interpreters of the mRNA codon sequence.  At the middle of the folded strand, there is a three-base coding sequence called the anticodon.  Each anticodon is complementary to a codon on the mRNA DNA, RNA, and Protein Chapter 12

Molecular Genetics 12.3 DNA, RNA, and Protein Chapter 12 Role of Ribosomes  Consists of two subunits  P site –where the complementary tRNA moves in.  A site – where the tRNA for the next codon moves in.  E site – exit site

Molecular Genetics 12.3 DNA, RNA, and Protein Chapter 12 Role of Ribosomes  rRNA forms bonds between the amino acids  Ribosomes continue until the A site contains a stop codon.

Molecular Genetics Chapter 12 Click on the link below into a web browser to see a video on transcription and translation: 12.3 DNA, RNA, and Protein Or copy and paste this link: hill.com/olcweb/cgi/pluginpop.cgi?it=swf::550::400::/sites/dl/free/ /383936/Vis_transcription_translation.swf::Visualizing %20Transcription%20and%20Translation Visualizing Transcription and Translation

12.3 DNA, RNA, and Protein Molecular Genetics One Gene— One Enzyme  The Beadle and Tatum experiment showed that one gene codes for one enzyme. We now know that one gene codes for one polypeptide. Chapter 12