RNA and Protein Synthesis Biology Rainier JrSr High

RNA and Protein Synthesis Biology Rainier Jr/Sr High School Mr. Taylor

RNA and Protein Synthesis n n DNA holds the "master code" for proteins, but it is RNA that does the work to make proteins. RNA = ribonucleic acid

RNA and Protein Synthesis n The RNA molecule is similar to the DNA molecule 1. The RNA molecule is made of strings of nucleotides. 2. The nitrogen bases follow the Base Pairing Rule.

RNA and Protein Synthesis n The RNA molecule is different than the DNA molecule. 1. RNA is a SINGLE helix. 2. The sugar in each nucleotide is RIBOSE. 3. The 4 nitrogen bases are Guanine n Cytosine n Adenine n URACIL (instead of Thymine) n

RNA and Protein Synthesis n There are 3 different types of RNA 1. messenger RNA (m. RNA): carries the genetic code from the nucleus to the ribosomes in the cytoplasm. 2. transfer RNA (t. RNA): carries the amino acids to the ribosomes. n (Proteins are simply long strings of small molecules called amino acids linked together. Proteins are polymers!) 3. ribosomal RNA (r. RNA): binds m. RNA and t. RNA together during protein synthesis.

RNA and Protein Synthesis n The "master code" carried by DNA must be transferred to m. RNA. • This coding is called TRANSCRIPTION.

RNA and Protein Synthesis • TRANSCRIPTION A segment of DNA unfolds and unzips. n Complementary pairs of RNA nucleotides are aligned and joined together. n THE NITROGEN BASES THAT ARE ADDED ARE THOSE OF RNA. n • DNA base Cytosine Guanine Thymine Adenine pairs with RNA base Guanine Cytosine Adenine Uracil

RNA and Protein Synthesis • TRANSCRIPTION If the DNA strand contains the following nitrogen bases ACGTTCCA AGTC UGCAAGGUUCAG the m. RNA strand will be created with these nitrogen bases

RNA and Protein Synthesis Each group of 3 nucleotides forms a codon. UGCAAGGUUCAG A codon codes for one amino acid. Strings of amino acids form proteins! With 4 nitrogen bases, this 3 base coding gives 43 (64) different combinations, more than enough for the 21 different amino acids.

RNA and Protein Synthesis • The table of amino acid codes is in your textbook on page 244 • UGC AAG GUU CAG

RNA and Protein Synthesis • TRANSLATION Takes place in the cytoplasm (ribosomes) n Involves codons on m. RNA matching up with anticodons on t. RNA. n Uses RNA code: A, U, C, G n m. RNA: U G C A A G G U U C A G n t. RNA: ACGUUCCAAGUC n

RNA and Protein Synthesis • Review: DNA is transcribed to m. RNA in the nucleus. n m. RNA exits the nucleus and attaches to a ribosome. n 3 -base codons on m. RNA are translated by matching anti-codons on t. RNA into the proper amino acid sequence to form a protein. n