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Chapter 12- DNA, RNA, and Proteins

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Chapter 12 lecture for Lab Bio

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Chapter 12- DNA, RNA, and Proteins

  1. 1. Copyright Pearson Prentice Hall Biology
  2. 2. 12–1 DNA Copyright Pearson Prentice Hall
  3. 3. Griffith and Transformation In 1928, British scientist Fredrick Griffith was trying to learn how certain types of bacteria caused pneumonia. He isolated two different strains of pneumonia bacteria from mice and grew them in his lab. Copyright Pearson Prentice Hall
  4. 4. Griffith made two observations: (1) The disease-causing strain of bacteria grew into smooth colonies on culture plates. (2) The harmless strain grew into colonies with rough edges.
  5. 5. Griffith's Experiments Griffith set up four individual experiments. Experiment 1: Mice were injected with the disease-causing strain of bacteria. The mice developed pneumonia and died. Copyright Pearson Prentice Hall
  6. 6. Experiment 2: Mice were injected with the harmless strain of bacteria. These mice didn’t get sick. Copyright Pearson Prentice Hall Harmless bacteria (rough colonies) Lives
  7. 7. Experiment 3: Griffith heated the disease-causing bacteria. He then injected the heat-killed bacteria into the mice. The mice survived. Copyright Pearson Prentice Hall Heat-killed disease-causing bacteria (smooth colonies) Lives
  8. 8. Experiment 4: Griffith mixed his heat-killed, disease-causing bacteria with live, harmless bacteria and injected the mixture into the mice. The mice developed pneumonia and died. Live disease-causing bacteria (smooth colonies) Copyright Pearson Prentice Hall Heat-killed disease-causing bacteria (smooth colonies) Harmless bacteria (rough colonies) Dies of pneumonia
  9. 9. deadly harmless dead deadly dead deadly + harmless Killed! Survived! Survived! Killed! Pneumonia Pneumonia Copyright Pearson Prentice Hall
  10. 10. Griffith concluded that the dead bacteria passed their disease-causing ability to the harmless strain. Live disease-causing bacteria (smooth colonies) Copyright Pearson Prentice Hall Heat-killed disease-causing bacteria (smooth colonies) Harmless bacteria (rough colonies) Dies of pneumonia
  11. 11. Transformation Griffith called this process transformation because the harmless strain of bacteria had changed into the disease-causing strain. Griffith hypothesized that a factor must contain information that could change harmless bacteria into disease-causing ones.
  12. 12. Avery and DNA Oswald Avery repeated Griffith’s work to determine which molecule was most important for transformation. Avery and his colleagues made an extract from the heat-killed bacteria that they treated with enzymes. Copyright Pearson Prentice Hall
  13. 13. The enzymes destroyed proteins, lipids, carbohydrates, and other molecules, including the nucleic acid RNA. Transformation still occurred. Copyright Pearson Prentice Hall
  14. 14. Avery and other scientists repeated the experiment using enzymes that would break down DNA. When DNA was destroyed, transformation did not occur. Therefore, they concluded that DNA was the transforming factor. Copyright Pearson Prentice Hall
  15. 15. The Hershey-Chase Experiment Alfred Hershey and Martha Chase studied viruses—nonliving particles smaller than a cell that can infect living organisms. Copyright Pearson Prentice Hall
  16. 16. Bacteriophages A virus that infects bacteria is known as a bacteriophage. Bacteriophages are composed of a DNA or RNA core and a protein coat. Copyright Pearson Prentice Hall
  17. 17. When a bacteriophage enters a bacterium, the virus attaches to the surface of the cell and injects its genetic information into it. Copyright Pearson Prentice Hall
  18. 18. The viral genes use the bacteria’s organelles to produce many new viruses, which eventually destroy the bacterium. The cell splits open as hundreds of new viruses burst out. Copyright Pearson Prentice Hall
  19. 19. If Hershey and Chase could determine which part of the virus entered an infected cell, they would learn whether genes were made of protein or DNA. They grew viruses in cultures containing radioactive isotopes of phosphorus-32 (32P) and sulfur-35 (35S). Copyright Pearson Prentice Hall
  20. 20. If 35S was found in the bacteria, it would mean that the viruses’ protein had been injected into the bacteria. Copyright Pearson Prentice Hall Bacteriophage with suffur-35 in protein coat Phage infects bacterium No radioactivity inside bacterium
  21. 21. If 32P was found in the bacteria, then it was the DNA that had been injected. Copyright Pearson Prentice Hall Bacteriophage with phosphorus-32 in DNA Phage infects bacterium Radioactivity inside bacterium
  22. 22. Nearly all the radioactivity in the bacteria was from phosphorus (32P). Hershey and Chase concluded that the genetic material of the bacteriophage was DNA. Copyright Pearson Prentice Hall
  23. 23. The nucleic acid DNA stores and transmits the genetic information from one generation of an organism to the next. Copyright Pearson Prentice Hall
  24. 24. DNA is a polymer made up of monomers called nucleotides. A nucleotide contains a five-carbon sugar, a phosphate group, and a nitrogenous base. Copyright Pearson Prentice Hall
  25. 25. In DNA the sugar is deoxyribose. DNA= deoxyribonucleic acid In RNA the sugar is ribose. RNA= ribonucleic acid Copyright Pearson Prentice Hall
  26. 26. Copyright Pearson Prentice Hall There are four kinds of bases in in DNA: •adenine •guanine •cytosine •thymine
  27. 27. The backbone of a DNA chain is formed by the sugar and phosphate groups of each nucleotide. The nucleotides can be joined together in any order. Copyright Pearson Prentice Hall
  28. 28. Chargaff's Rules Erwin Chargaff discovered that: •The percentages of guanine [G] and cytosine [C] bases are almost equal in any sample of DNA. •The percentages of adenine [A] and thymine [T] bases are almost equal in any sample of DNA. Copyright Pearson Prentice Hall
  29. 29. X-Ray Evidence Rosalind Franklin used X-ray diffraction to get information about the structure of DNA. She aimed an X-ray beam at concentrated DNA samples and recorded the scattering pattern of the X-rays on film. Copyright Pearson Prentice Hall
  30. 30. Using clues from Franklin’s pattern, James Watson and Francis Crick built a model that explained how DNA carried information and could be copied. Watson and Crick's model of DNA was a double helix, in which two strands were wound around each other. Copyright Pearson Prentice Hall
  31. 31. Copyright Pearson Prentice Hall DNA Double Helix
  32. 32. Watson and Crick discovered that hydrogen bonds can form only between certain base pairs—adenine and thymine, and guanine and cytosine. This principle is called base pairing. adenine(A) pairs with thymine(T) guanine(G) pairs with cytosine(C) Copyright Pearson Prentice Hall
  33. 33. Copyright Pearson Prentice Hall
  34. 34. 12–2 Chromosomes and DNA Replication 12-2 Chromosomes and DNA Replication Copyright Pearson Prentice Hall
  35. 35. DNA and Chromosomes • In prokaryotic cells, DNA is located in the cytoplasm. •Most prokaryotes have a single DNA molecule containing nearly all of the cell’s genetic information. Copyright Pearson Prentice Hall
  36. 36. Copyright Pearson Prentice Hall Chromosome E. Coli Bacterium Bases on the Chromosomes
  37. 37. Many eukaryotes have 1000 times the amount of DNA as prokaryotes. Eukaryotic DNA is located in the cell nucleus inside chromosomes. The number of chromosomes varies widely from one species to the next. Copyright Pearson Prentice Hall
  38. 38. Eukaryotic chromosomes contain DNA and protein, tightly packed together to form chromatin. •Chromatin consists of DNA tightly coiled around proteins called histones. •DNA and histone molecules form nucleosomes. •Nucleosomes pack together, forming a thick fiber.
  39. 39. Eukaryotic Chromosome Structure Chromosome Nucleosome Coils Copyright Pearson Prentice Hall Supercoils DNA double helix Histones
  40. 40. DNA Replication •Each strand of the DNA double helix has all the information needed to reconstruct the other half by the mechanism of base pairing. • In most prokaryotes, DNA replication begins at a single point and continues in two directions. Copyright Pearson Prentice Hall
  41. 41. In eukaryotic chromosomes, DNA replication occurs at hundreds of places. Replication proceeds in both directions until each chromosome is completely copied. The sites where separation and replication occur are called replication forks. Copyright Pearson Prentice Hall
  42. 42. •Before a cell divides, its DNA is duplicated in a process called replication. •Replication ensures that each resulting cell will have a complete set of DNA. Copyright Pearson Prentice Hall
  43. 43. During DNA replication, the DNA molecule separates into two strands, then produces two new complementary strands following the rules of base pairing. Each strand of the double helix of DNA serves as a template for the new strand. Copyright Pearson Prentice Hall
  44. 44. New Strand Original strand Growth Growth Copyright Pearson Prentice Hall Nitrogen Bases Replication Fork Replication Fork DNA Polymerase Active Art
  45. 45. How Replication Occurs •DNA replication is carried out by enzymes that “unzip” a molecule of DNA. •Hydrogen bonds between base pairs are broken and the two strands of DNA unwind. Copyright Pearson Prentice Hall
  46. 46. The main enzyme involved in DNA replication is DNA polymerase. DNA polymerase joins individual nucleotides and then “proofreads” each new DNA strand. Copyright Pearson Prentice Hall
  47. 47. 12-3 RNA and Protein Synthesis 12–3 RNA and Protein Synthesis Copyright Pearson Prentice Hall
  48. 48. Genes are coded DNA instructions that control the production of proteins. Genetic messages can be decoded by copying part of the nucleotide sequence from DNA into RNA. RNA contains coded information for making proteins. Copyright Pearson Prentice Hall
  49. 49. The Structure of RNA •RNA consists of a long chain of nucleotides. •Each nucleotide is made up of a 5- carbon sugar, a phosphate group, and a nitrogenous base. Copyright Pearson Prentice Hall
  50. 50. There are three main differences between RNA and DNA: •The sugar in RNA is ribose instead of deoxyribose. •RNA is generally single-stranded. •RNA contains uracil in place of thymine. Copyright Pearson Prentice Hall
  51. 51. There are three main types of RNA: •messenger RNA •ribosomal RNA •transfer RNA Copyright Pearson Prentice Hall
  52. 52. Messenger RNA (mRNA) carries copies of instructions for assembling amino acids into proteins. Copyright Pearson Prentice Hall
  53. 53. Ribosome Ribosomal RNA Ribosomes are made up of proteins and ribosomal RNA (rRNA). Copyright Pearson Prentice Hall
  54. 54. Amino acid Transfer RNA During protein construction, transfer RNA (tRNA) transfers each amino acid to the ribosome.
  55. 55. •RNA molecules are produced by copying part of a nucleotide sequence of DNA into a complementary sequence in RNA. This process is called transcription. •Transcription requires the enzyme RNA polymerase. Copyright Pearson Prentice Hall
  56. 56. During transcription, RNA polymerase binds to DNA and separates the DNA strands. RNA polymerase then uses one strand of DNA as a template to make a strand of RNA. Copyright Pearson Prentice Hall
  57. 57. RNA polymerase binds only to regions of DNA known as promoters. Promoters are signals in DNA that tell RNA polymerase where to bind, so it can start the transcription of RNA. Copyright Pearson Prentice Hall
  58. 58. Transcription RNA RNA polymerase Copyright Pearson Prentice Hall DNA
  59. 59. RNA Editing •The DNA of eukaryotic genes contains sequences of nucleotides, called introns, that are not involved in coding for proteins. •The DNA sequences that code for proteins are called exons. •When RNA molecules are formed, introns and exons are copied from DNA. Copyright Pearson Prentice Hall
  60. 60. The introns are cut out of RNA molecules. The exons are the spliced together to form mRNA. Exon Intron DNA Copyright Pearson Prentice Hall Pre-mRNA mRNA Cap Tail
  61. 61. The Genetic Code •The genetic code is the “language” of mRNA instructions. •The genetic code is written using four “letters” (the bases: A, U, C, and G). Copyright Pearson Prentice Hall
  62. 62. A codon consists of three consecutive nucleotides on mRNA that specify a particular amino acid. Copyright Pearson Prentice Hall
  63. 63. •Each codon codes for a specific amino acid. •Some amino acids have more than one codon. Copyright Pearson Prentice Hall
  64. 64. The Genetic Code Copyright Pearson Prentice Hall
  65. 65. •Codon AUG is the“start” codon or it can specify the amino acid methionine. •There are three “stop” codons that do not code for any amino acid. These “stop” codons signify the end of a polypeptide. Copyright Pearson Prentice Hall
  66. 66. Translation is the decoding of an mRNA message into a polypeptide chain (protein). Translation takes place on ribosomes. During translation, the cell uses information from messenger RNA to produce proteins. Copyright Pearson Prentice Hall
  67. 67. Messenger RNA is transcribed and introns are removed in the nucleus. Then mRNA enters the cytoplasm and attaches to a ribosome. Copyright Pearson Prentice Hall Nucleus mRNA Active Art
  68. 68. Translation begins when an mRNA molecule attaches to a ribosome. As each codon of the mRNA molecule moves through the ribosome, the proper amino acid is brought in by tRNA. In the ribosome, the amino acid is transferred to the growing polypeptide chain. Copyright Pearson Prentice Hall
  69. 69. Each tRNA molecule carries only one kind of amino acid. In addition to an amino acid, each tRNA molecule has three unpaired bases, called the anticodon. The anticodon on tRNA is complementary to one mRNA codon. Copyright Pearson Prentice Hall
  70. 70. The ribosome binds new tRNA molecules and amino acids as it moves along the mRNA. Phenylalanine tRNA Lysine Copyright Pearson Prentice Hall Methionine Ribosome mRNA Start codon
  71. 71. Copyright Pearson Prentice Hall Protein Synthesis tRNA Ribosome mRNA Lysine Translation direction
  72. 72. •The process continues until the ribosome reaches a stop codon. Polypeptide Copyright Pearson Prentice Hall Ribosome tRNA mRNA
  73. 73. The Roles of RNA and DNA •The cell uses the DNA “master plan” to prepare RNA “blueprints.” The DNA stays in the nucleus. •The RNA molecules go to the protein building sites in the cytoplasm—the ribosomes. Copyright Pearson Prentice Hall
  74. 74. Genes and Proteins •Genes contain instructions for assembling proteins. •Many proteins are enzymes, which catalyze and regulate chemical reactions. • Proteins are each specifically designed to build or operate a component of a living cell. Copyright Pearson Prentice Hall
  75. 75. The sequence of bases in DNA is used as a template for mRNA. The codons of mRNA specify the sequence of amino acids in a protein. Codon Codon Codon Single strand of DNA Codon Codon Codon Copyright Pearson Prentice Hall mRNA Alanine Arginine Leucine Amino acids within a polypeptide
  76. 76. Copyright Pearson Prentice Hall 12-4 Mutations 12–4 Mutations
  77. 77. Mutations are changes in the genetic material. Copyright Pearson Prentice Hall
  78. 78. Kinds of Mutations •Mutations that produce changes in a single gene are known as gene mutations. •Mutations that produce changes in whole chromosomes are known as chromosomal mutations. Copyright Pearson Prentice Hall
  79. 79. Gene Mutations •Gene mutations involving a change in one or a few nucleotides are known as point mutations because they occur at a single point in the DNA sequence. •Point mutations include substitutions, insertions, and deletions. Copyright Pearson Prentice Hall
  80. 80. Substitution– Switching one nucleotide for another, usually affects only a single amino acid. Copyright Pearson Prentice Hall
  81. 81. The effects of insertions or deletions are more dramatic. The addition or deletion of a nucleotide causes a shift in the grouping of codons. Changes like these are called frameshift mutations. Copyright Pearson Prentice Hall
  82. 82. Frameshift mutations may change every amino acid that follows the point of the mutation. Frameshift mutations can alter a protein so much that it is unable to perform its normal functions. Copyright Pearson Prentice Hall
  83. 83. Insertion-- An extra base is added, so the reading frame is shifted. Copyright Pearson Prentice Hall
  84. 84. Deletion-- a single base is lost so the reading frame is shifted. Copyright Pearson Prentice Hall
  85. 85. Chromosomal Mutations •Chromosomal mutations involve changes in the number or structure of chromosomes. •Chromosomal mutations include deletions, duplications, inversions, and translocations. Copyright Pearson Prentice Hall
  86. 86. Deletions involve the loss of all or part of a chromosome. Copyright Pearson Prentice Hall
  87. 87. •Duplications produce extra copies of parts of a chromosome. Copyright Pearson Prentice Hall
  88. 88. Inversions reverse the direction of parts of chromosomes. Copyright Pearson Prentice Hall
  89. 89. Translocations occurs when part of one chromosome breaks off and attaches to another. Copyright Pearson Prentice Hall
  90. 90. Significance of Mutations Many mutations have little or no effect on gene expression. •Some mutations are the cause of genetic disorders. •Beneficial mutations may produce proteins with new or altered activities that can be useful. Copyright Pearson Prentice Hall
  91. 91. Polyploidy is the condition in which an organism has extra sets of chromosomes. Copyright Pearson Prentice Hall
  92. 92. 12-5 Gene Regulation Fruit fly chromosome Copyright Pearson Prentice Hall 12-5 Gene Regulation Fruit fly embryo Adult fruit fly Mouse chromosomes Mouse embryo Adult mouse
  93. 93. Gene Regulation: An Example •E. coli provides an example of how gene expression can be regulated. •An operon is a group of genes that operate together. •In E. coli, the lac operon genes must be turned on so the bacterium can use lactose as food. Copyright Pearson Prentice Hall
  94. 94. The lac genes are turned off by repressors and turned on by the presence of lactose. Copyright Pearson Prentice Hall
  95. 95. On one side of the operon's three genes are two regulatory regions. • In the promoter (P) region, RNA polymerase binds and then begins transcription. Copyright Pearson Prentice Hall
  96. 96. •The other region is the operator (O). Copyright Pearson Prentice Hall
  97. 97. When the lac repressor binds to the O region, transcription is not possible. Copyright Pearson Prentice Hall
  98. 98. When lactose is added it binds to the repressor proteins making them fall off. Copyright Pearson Prentice Hall
  99. 99. The repressor protein changes shape and falls off the operator and transcription is made possible. Copyright Pearson Prentice Hall
  100. 100. Many genes are regulated by repressor proteins. Some genes use proteins that speed transcription. Sometimes regulation occurs at the level of protein synthesis. Copyright Pearson Prentice Hall
  101. 101. Eukaryotic Gene Regulation Operons are generally not found in eukaryotes. Most eukaryotic genes are controlled individually and have regulatory sequences that are much more complex than those of the lac operon. Copyright Pearson Prentice Hall
  102. 102. Many eukaryotic genes have a sequence called the TATA box. Copyright Pearson Prentice Hall Promoter sequences Upstream enhancer TATA box Introns Exons Direction of transcription
  103. 103. Eukaryotic Gene Regulation The TATA box seems to help position RNA polymerase. Copyright Pearson Prentice Hall Promoter sequences Upstream enhancer TATA box Introns Exons Direction of transcription
  104. 104. Eukaryotic promoters are usually found just before the TATA box, and consist of short DNA sequences. Promoter sequences Copyright Pearson Prentice Hall Upstream enhancer TATA box Introns Exons Direction of transcription
  105. 105. Genes are regulated in a variety of ways by enhancer sequences. Many proteins can bind to different enhancer sequences. Some DNA-binding proteins enhance transcription by: •opening up tightly packed chromatin •helping to attract RNA polymerase •blocking access to genes.
  106. 106. •As cells grow and divide, they undergo differentiation, meaning they become specialized in structure and function. •Hox genes control the differentiation of cells and tissues in the embryo. Copyright Pearson Prentice Hall
  107. 107. Careful control of expression in hox genes is essential for normal development. All hox genes are descended from the genes of common ancestors. Copyright Pearson Prentice Hall
  108. 108. Development and Differentiation Copyright Pearson Prentice Hall Hox Genes Fruit fly chromosome Fruit fly embryo Adult fruit fly Mouse chromosomes Mouse embryo Adult mouse
  109. 109. Copyright Pearson Prentice Hall 12–1 Avery and other scientists discovered that a. DNA is found in a protein coat. b. DNA stores and transmits genetic information from one generation to the next. c. transformation does not affect bacteria. d. proteins transmit genetic information from one generation to the next.
  110. 110. Copyright Pearson Prentice Hall 12–1 The Hershey-Chase experiment was based on the fact that a. DNA has both sulfur and phosphorus in its structure. b. protein has both sulfur and phosphorus in its structure. c. both DNA and protein have no phosphorus or sulfur in their structure. d. DNA has phosphorus, while protein has sulfur in its structure.
  111. 111. Copyright Pearson Prentice Hall 12–1 DNA is a long molecule made of monomers called a. nucleotides. b. purines. c. pyrimidines. d. sugars.
  112. 112. Copyright Pearson Prentice Hall 12–1 Chargaff's rules state that the number of guanine nucleotides must equal the number of a. cytosine nucleotides. b. adenine nucleotides. c. thymine nucleotides. d. thymine plus adenine nucleotides.
  113. 113. Copyright Pearson Prentice Hall 12–1 In DNA, the following base pairs occur: a. A with C, and G with T. b. A with T, and C with G. c. A with G, and C with T. d. A with T, and C with T.
  114. 114. Copyright Pearson Prentice Hall 12–2 In prokaryotic cells, DNA is found in the a. cytoplasm. b. nucleus. c. ribosome. d. cell membrane.
  115. 115. Copyright Pearson Prentice Hall 12–2 The first step in DNA replication is a. producing two new strands. b. separating the strands. c. producing DNA polymerase. d. correctly pairing bases.
  116. 116. Copyright Pearson Prentice Hall 12–2 A DNA molecule separates, and the sequence GCGAATTCG occurs in one strand. What is the base sequence on the other strand? a. GCGAATTCG b. CGCTTAAGC c. TATCCGGAT d. GATGGCCAG
  117. 117. Copyright Pearson Prentice Hall 12–2 In addition to carrying out the replication of DNA, the enzyme DNA polymerase also functions to a. unzip the DNA molecule. b. regulate the time copying occurs in the cell cycle. c. “proofread” the new copies to minimize the number of mistakes. d. wrap the new strands onto histone proteins.
  118. 118. Copyright Pearson Prentice Hall 12–2 The structure that may play a role in regulating how genes are “read” to make a protein is the a. coil. b. histone. c. nucleosome. d. chromatin.
  119. 119. Copyright Pearson Prentice Hall 12–3 The role of a master plan in a building is similar to the role of which molecule? a. messenger RNA b. DNA c. transfer RNA d. ribosomal RNA
  120. 120. Copyright Pearson Prentice Hall 12–3 A base that is present in RNA but NOT in DNA is a. thymine. b. uracil. c. cytosine. d. adenine.
  121. 121. Copyright Pearson Prentice Hall 12–3 The nucleic acid responsible for bringing individual amino acids to the ribosome is a. transfer RNA. b. DNA. c. messenger RNA. d. ribosomal RNA.
  122. 122. Copyright Pearson Prentice Hall 12–3 A region of a DNA molecule that indicates to an enzyme where to bind to make RNA is the a. intron. b. exon. c. promoter. d. codon.
  123. 123. Copyright Pearson Prentice Hall 12–3 A codon typically carries sufficient information to specify a(an) a. single base pair in RNA. b. single amino acid. c. entire protein. d. single base pair in DNA.
  124. 124. Copyright Pearson Prentice Hall 12–4 A mutation in which all or part of a chromosome is lost is called a(an) a. duplication. b. deletion. c. inversion. d. point mutation.
  125. 125. Copyright Pearson Prentice Hall 12–4 A mutation that affects every amino acid following an insertion or deletion is called a(an) a. frameshift mutation. b. point mutation. c. chromosomal mutation. d. inversion.
  126. 126. Copyright Pearson Prentice Hall 12–4 A mutation in which a segment of a chromosome is repeated is called a(an) a. deletion. b. inversion. c. duplication. d. point mutation.
  127. 127. Copyright Pearson Prentice Hall 12–4 The type of point mutation that usually affects only a single amino acid is called a. a deletion. b. a frameshift mutation. c. an insertion. d. a substitution.
  128. 128. Copyright Pearson Prentice Hall 12–4 When two different chromosomes exchange some of their material, the mutation is called a(an) a. inversion. b. deletion. c. substitution. d. translocation.
  129. 129. Copyright Pearson Prentice Hall 12–5 Which sequence shows the typical organization of a single gene site on a DNA strand? a. start codon, regulatory site, promoter, stop codon b. regulatory site, promoter, start codon, stop codon c. start codon, promoter, regulatory site, stop codon d. promoter, regulatory site, start codon, stop codon
  130. 130. Copyright Pearson Prentice Hall 12–5 A group of genes that operates together is a(an) a. promoter. b. operon. c. operator. d. intron.
  131. 131. Copyright Pearson Prentice Hall 12–5 Repressors function to a. turn genes off. b. produce lactose. c. turn genes on. d. slow cell division.
  132. 132. Copyright Pearson Prentice Hall 12–5 Which of the following is unique to the regulation of eukaryotic genes? a. promoter sequences b. TATA box c. different start codons d. regulatory proteins
  133. 133. Copyright Pearson Prentice Hall 12–5 Organs and tissues that develop in various parts of embryos are controlled by a. regulation sites. b. RNA polymerase. c. hox genes. d. DNA polymerase.

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