Ljnpoj Essay

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Name Class Date RNA and Protein Synthesis Information and Heredity Q: How does information flow from DNA to RNA to direct the synthesis of proteins? WHAT I KNOW SAMPLE ANSWER: WHAT I LEARNED SAMPLE ANSWER: 13.1 What is RNA? RNA is a nucleic acid that carries coded genetic information. RNA contains the sugar ribose and the nitrogenous base uracil instead of thymine. It is usually a single strand. mRNA molecules are made using DNA as a template. SAMPLE ANSWER: 13.2 How do cells make proteins? The bases in DNA—A, T, G, and C—form a four-letter “alphabet” that writes the “words” of the genetic code. The genetic code is read in mRNA codons, which are sequences of three bases that correspond to a single amino acid. Ribosomes use the sequence of codons to assemble amino acids into polypeptides. SAMPLE ANSWER: SAMPLE ANSWER: 13.3 What happens when a cell’s DNA changes? When DNA changes, mistakes can be made. The organism may look or function differently. SAMPLE ANSWER: Mutations are heritable changes in genetic information. They can involve only one DNA nucleotide or the whole chromosome. Mutations may or may not affect gene function. SAMPLE ANSWER: 13.4 How do cells regulate gene expression? Cell proteins regulate gene expression. SAMPLE ANSWER: DNA-binding proteins regulate genes by controlling transcription in prokaryotes. In eukaryotes, transcription factors control gene expression by binding DNA sequences in the regulatory regions. Chapter 13 • Workbook A • Copyright © by Pearson Education, Inc., or its affiliates. All Rights Reserved. 193 Name Class Date 13.1 RNA Lesson Objectives Contrast RNA and DNA. Explain the process of transcription. Lesson Summary The Role of RNA RNA (ribonucleic acid) is a nucleic acid like DNA. It consists of a long chain of nucleotides. The RNA base

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