Chapter 12 Molecular Genetics Section 1 DNA The

Chapter 12 Molecular Genetics Section 1: DNA: The Genetic Material Section 2: Replication of DNA Section 3: DNA, RNA, and Protein Section 4: Gene Regulation and Mutation Click on a lesson name to select.

BELLRINGER!!! Answer each question below in your science notebook. 1. What questions do you think explorers asked when they first saw the Great Sphinx? 2. If you were to study the Great Sphinx, what do you think you could learn about the people who built it? 3. What questions do you think scientists asked when they began to understand the genetic basis of life?

1. Answers will vary. Students might suggest that explorers wanted to know who built the Sphinx, why, and how. 2. Answers will vary. Students might suggest that they could learn about the technological capabilities, culture, or beliefs of the people involved. 3. Answers will vary. Students might suggest that, among other things, scientists wanted to know how genetic information was replicated and transported to new cells.

How do we know how to build things? Click on a lesson name to select.

DNA: The Genetic Material (Section 12. 1) MAIN IDEA: The discovery that DNA is the genetic code involved many experiments.

Chapter 12 Molecular Genetics DNA: The Genetic Material (Section 12. 1) Objectives: • Summarize the experiments leading to the discovery of DNA as the genetic material. • Diagram and label the basic structure of DNA. • Describe the basic structure of the eukaryotic chromosome.

Chapter 12 Molecular Genetics Review Vocabulary nucleic acid – complex biomolecule that stores cellular information in the form of a code protein – organic compound made of amino acids joined by peptide bonds; primary building block of organisms macromolecule – large molecule formed by joining smaller organic molecules together

Chapter 12 Molecular Genetics New Vocabulary double helix nucleosome

Chapter 12 Molecular Genetics DNA: The Genetic Material (Section 12. 1) Scientists knew that genetic information was carried on the chromosome in eukaryotic cells, and that the two main components of chromosomes are DNA and protein.

Chapter 12 Molecular Genetics THE BLUEPRINT: DNA or proteins? The race to find the genetic material was split into two groups: those who thought the genetic material was protein and those who thought the genetic material was DNA.

Chapter 12 Molecular Genetics 12. 1 DNA: The Genetic Material Griffith § Performed the first major experiment that led to the discovery of DNA as the genetic material.

Chapter 12 Molecular Genetics 12. 1 DNA: The Genetic Material Avery § Identified the molecule that transformed the R strain of bacteria into the S strain § Concluded that when the S cells were killed, DNA was released. § R bacteria incorporated this DNA into their cells and changed into S cells.

Chapter 12 Molecular Genetics 12. 1 DNA: The Genetic Material Hershey and Chase § Used radioactive labeling (via viruses) to trace the DNA and protein. § Concluded that the viral DNA was injected into the cell and provided the genetic information needed to produce new viruses

Chapter 12 Molecular Genetics 12. 1 DNA: The Genetic Material DNA Structure § Nucleotides § consist of a five-carbon 1) sugar, a 2) phosphate group, and a nitrogenous 3) base

Chapter 12 Molecular Genetics 12. 1 DNA: The Genetic Material Chargaff § Chargaff’s rule: C = G and A = T

Chapter 12 Molecular Genetics The Pieces of the Puzzle • Franklin’s Discovery Chemist Rosalind Franklin was able to make images of DNA molecules by using X-ray diffraction.

DNA = “double helix” or “twisted ladder”

Chapter 12 Molecular Genetics 12. 1 DNA: The Genetic Material Watson and Crick § Built a model of the double helix that conformed to the others’ research 1. two outside strands consist of alternating phosphate 2. deoxyribose cytosine and guanine bases pair to each by three hydrogen bonds 3. other thymine and adenine bases pair to each other by two hydrogen bonds

Chapter 12 Molecular Genetics DNA Structure § DNA often is compared to a twisted ladder. § Rails of the ladder are represented by the alternating deoxyribose and phosphate. § The pairs of bases (cytosine–guanine or thymine–adenine) form the steps.

Chapter 12 Molecular Genetics • http: //glencoe. mcgrawhill. com/sites/0078695104/student_view 0/uni t 3/chapter 12/concepts_in_motion. html#

Chapter 12 Molecular Genetics 12. 1 DNA: The Genetic Material Orientation § On the top rail, the strand is said to be oriented 5′ to 3′. § The strand on the bottom runs in the opposite direction and is oriented 3′ to 5′.

Chapter 12 Molecular Genetics Alabama Science in Motion Lab “DNA Model Kit”

Chapter 12 Molecular Genetics 12. 1 DNA: The Genetic Material Chromosome Structure § DNA coils around histones to form nucleosomes, which coil to form chromatin fibers. § The chromatin fibers supercoil to form chromosomes that are visible in the metaphase stage of mitosis.

Chromosome Structure • In prokaryotes, the DNA molecule is contained in the cytoplasm and consists mainly of a ring of DNA and associated proteins. • Eukaryotic DNA is organized into individual chromosomes. • If a DNA strand 140 million nucleotides long was laid out in a straight line, it would be about five centimeters long.

Section 12. 1 Summary • Griffith’s bacterial experiment and Avery’s • • • explanation first indicated that DNA is genetic material. The Hershey-Chase experiment provided evidence that DNA is the genetic material of viruses. Chargaff’s rule states that, in DNA, the amount of cytosine equals the amount of guanine and the amount of thymine equals the amount of adenine. The work of Watson, Crick, Franklin, and Wilkins provided evidence of the doublehelix structure of DNA.

Chapter 12 Molecular Genetics Replication of DNA MAIN IDEA: DNA replicates by making a strand that is complementary to each original strand.

Replication of DNA (Section 12. 2) Objectives n Summarize the role of the enzymes involved in the replication of DNA. n Explain how leading and lagging strands are synthesized differently.

Review Vocabulary template – a molecule of DNA that is a pattern for synthesis for a new DNA molecule

New Vocabulary semiconservative replication DNA polymerase Okazaki fragment

Chapter 12 Molecular Genetics 12. 2 Replication of DNA Semiconservative Replication § Parental strands of DNA separate, serve as templates, and produce DNA molecules that have one strand of parental DNA and one strand of new DNA.

Chapter 12 Molecular Genetics 12. 2 Replication of DNA Unwinding § DNA helicase, an enzyme, is responsible for unwinding and unzipping the double helix. § RNA primase adds a short segment of RNA, called an RNA primer, on each DNA strand.

Chapter 12 Molecular Genetics 12. 2 Replication of DNA Base pairing § DNA polymerase continues adding appropriate nucleotides to the chain by adding to the 3′ end of the new DNA strand.

Chapter 12 Molecular Genetics

Chapter 12 Molecular Genetics 12. 2 Replication of DNA § One strand is called the leading strand is elongated as the DNA unwinds. § The other strand of DNA, called the lagging strand, elongates away from the replication fork. § The lagging strand is synthesized discontinuously into small segments, called Okazaki fragments.

Chapter 12 Molecular Genetics 12. 2 Replication of DNA Joining § DNA polymerase removes the RNA primer and fills in the place with DNA nucleotides. § DNA ligase links the two sections.

Chapter 12 Molecular Genetics 12. 2 Replication of DNA Comparing DNA Replication in Eukaryotes and Prokaryotes § Eukaryotic DNA unwinds in multiple areas as DNA is replicated. § In prokaryotes, the circular DNA strand is opened at one origin of replication. § Prokaryotes DNA typically is shorter than eukaryotic DNA and remains in the cytoplasm.

Section 12. 2 Summary • The enzymes DNA helicase, RNA primase, DNA polymerase, and DNA ligase are involved in DNA replication. • The leading strand is synthesized continuously, but the lagging strand is synthesized discontinuously, forming Okazaki fragments. • Prokaryotic DNA opens at a single origin of replication, whereas eukaryotic DNA has multiple areas of replication.

Chapter 12 Molecular Genetics DNA, RNA, and Protein (Section 12. 3) MAIN IDEA: DNA codes for RNA, which guides protein synthesis.

DNA, RNA, and Protein (Section 12. 3) Objectives: n n n Explain how messenger RNA, ribosomal RNA, and transfer RNA are involved in the transcription and translation of genes. Summarize the role of RNA polymerase in the synthesis of messenger RNA. Describe how the code of DNA is translated into messenger RNA and is utilized to synthesize a particular protein.

Chapter 12 Molecular Genetics Review Vocabulary synthesis – the composition or combination of parts to form a whole. (Glencoe) synthesis – the uniting or building up of substances into a compound. (Webster’s)

Chapter 12 Molecular Genetics New Vocabulary RNA messenger RNA (m. RNA) ribosomal RNA (r. RNA) transfer RNA (t. RNA) transcription RNA polymerase codon intron exon translation

Chapter 12 Molecular Genetics 12. 3 DNA, RNA, and Protein Central Dogma (reading and expressing genes = DNA > RNA > protein) “DNA codes for RNA which guides the synthesis of proteins. ” § RNA § Contains the sugar ribose and the base uracil § Usually is single stranded dogma – something held as an established opinion; a point of view

Chapter 12 Molecular Genetics 12. 3 DNA, RNA, and Protein Messenger RNA (m. RNA) § Long strands of RNA nucleotides that are formed complementary to one strand of DNA Ribosomal RNA (r. RNA) § Associates with proteins to form ribosomes in the cytoplasm Transfer RNA (t. RNA) § Smaller segments of RNA nucleotides that transport amino acids to the ribosome

Chapter 12 Molecular Genetics 12. 3 DNA, RNA, and Protein

Chapter 12 Molecular Genetics

Chapter 12 Molecular Genetics 12. 3 DNA, RNA, and Protein Transcription § Through transcription, the DNA code is transferred to m. RNA in the nucleus. § DNA is unzipped in the nucleus and RNA polymerase binds to a specific section where an m. RNA will be synthesized.

Chapter 12 Molecular Genetics

Chapter 12 Molecular Genetics 12. 3 DNA, RNA, and Protein RNA Processing § The code on the DNA is interrupted periodically by sequences that are not in the final m. RNA. § Intervening sequences are called introns. § Remaining pieces of DNA that serve as the coding sequences are called exons. DNA and Genes

Chapter 12 Molecular Genetics 12. 3 DNA, RNA, and Protein The Code § Experiments during the 1960 s demonstrated that the DNA code was a three-base code. § The three-base code in DNA or m. RNA is called a codon.

Chapter 12 Molecular Genetics 12. 3 DNA, RNA, and Protein Translation § In translation, t. RNA molecules act as the interpreters of the m. RNA 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 m. RNA.

Chapter 12 Molecular Genetics 12. 3 DNA, RNA, and Protein Visualizing Transcription and Translation

Chapter 12 Molecular Genetics 12. 3 DNA, RNA, and Protein 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.

Section 12. 3 Summary • Three major types of RNA are involved in protein synthesis: m. RNA, t. RNA, and r. RNA. • The synthesis of the m. RNA from the template DNA is called transcription. • Translation is the process through which the m. RNA attaches to the ribosome and a protein is assembled. • In eukaryotes, the m. RNA contains introns that are excised before leaving the nucleus. A cap and poly-A tail also are added to the m. RNA.

Chapter 12 Molecular Genetics Gene Regulation and Mutation (Section 12. 4) MAIN IDEA: Gene expression is regulated by the cell, and mutations can affect this expression.

Gene Regulation and Mutation (Section 12. 4) Objectives n Describe how bacteria are able to regulate their genes by two types operons. n Discuss how eukaryotes regulate transcription of gene. n Summarize the various types of mutations.

Chapter 12 Molecular Genetics Review Vocabulary prokaryote – organism that does not have (1) membrane-bound organelles and (2) DNA that is organized in chromosomes eukaryotic – unicellular organism with membrane bound organelles; generally larger and more complex than a prokaryotic cell.

Chapter 12 Molecular Genetics New Vocabulary gene regulation operon mutation mutagen

Chapter 12 Molecular Genetics 12. 4 Gene Regulation and Mutation Prokaryote Gene Regulation § Ability of an organism to control which genes are transcribed in response to the environment § An operon is a section of DNA that contains the genes for the proteins needed for a specific metabolic pathway. § Operator § Promoter § Regulatory gene § Genes coding for proteins

Chapter 12 Molecular Genetics 12. 4 Gene Regulation and Mutation The Trp Operon

Chapter 12 Molecular Genetics 12. 4 Gene Regulation and Mutation The Lac Operon Lac-Trp Operon

Chapter 12 Molecular Genetics 12. 4 Gene Regulation and Mutation Eukaryote Gene Regulation § Controlling transcription § Transcription factors ensure that a gene is used at the right time and that proteins are made in the right amounts § The complex structure of eukaryotic DNA also regulates transcription.

Chapter 12 Molecular Genetics 12. 4 Gene Regulation and Mutation Hox Genes § Hox genes are responsible for the general body pattern of most animals.

Chapter 12 Molecular Genetics 12. 4 Gene Regulation and Mutation RNA Interference § RNA interference can stop the m. RNA from translating its message.

Chapter 12 Molecular Genetics 12. 4 Gene Regulation and Mutations § A permanent change that occurs in a cell’s DNA is called a mutation. § Types of mutations § Point mutation § Insertion § Deletion

Chapter 12 Molecular Genetics 12. 4 Gene Regulation and Mutation

Chapter 12 Molecular Genetics 12. 4 Gene Regulation and Mutation Protein Folding and Stability § Substitutions also can lead to genetic disorders. § Can change both the folding and stability of the protein

Chapter 12 Molecular Genetics 12. 4 Gene Regulation and Mutation Causes of Mutation § Can occur spontaneously § Chemicals and radiation also can damage DNA. § High-energy forms of radiation, such as X rays and gamma rays, are highly mutagenic.

Chapter 12 Molecular Genetics 12. 4 Gene Regulation and Mutation Body-cell v. Sex-cell Mutation § Somatic cell mutations are not passed on to the next generation. § Mutations that occur in sex cells (germ-line cells) are passed on to the organism’s offspring and will be present in every cell of the offspring.

Section 12. 4 Summary • Prokaryotic cells regulate their protein synthesis through a set of genes called operons. • Eukaryotic cells regulate their protein synthesis using various transcription factors, eukaryotic nucleosome structures, and RNA interference. • Mutations range from point mutations to the deletion or movement of large sections of the chromosome. • Mutagens, such as chemicals and radiation, can cause mutations.

Chapter 12 Molecular Genetics Chapter Resource Menu Chapter Diagnostic Questions Formative Test Questions Chapter Assessment Questions Standardized Test Practice biologygmh. com Glencoe Biology Transparencies Image Bank Vocabulary Animation Click on a hyperlink to view the corresponding lesson.

Chapter 12 Molecular Genetics Chapter Diagnostic Questions Which scientist(s) definitively proved that DNA transfers genetic material? A. Watson and Crick B. Mendel C. Hershey and Chase D. Avery

Chapter 12 Molecular Genetics Chapter Diagnostic Questions Name the small segments of the lagging DNA strand. A. ligase B. Okazaki fragments C. polymerase D. helicase

Chapter 12 Molecular Genetics Chapter Diagnostic Questions Which is not true of RNA? A. It contains the sugar ribose. B. It contains the base uracil. C. It is single-stranded. D. It contains a phosphate.

Chapter 12 Molecular Genetics 12. 1 Formative Questions The experiments of Avery, Hershey and Chase provided evidence that the carrier of genetic information is _______. A. carbohydrate B. DNA C. lipid D. protein

Chapter 12 Molecular Genetics 12. 1 Formative Questions What is the base-pairing rule for purines and pyrimidines in the DNA molecule? A. A—G and C—T B. A—T and C—G C. C—A and G—T D. C—U and A—G

Chapter 12 Molecular Genetics 12. 1 Formative Questions What are chromosomes composed of? A. chromatin and histones B. DNA and protein C. DNA and lipids D. protein and centromeres

Chapter 12 Molecular Genetics 12. 2 Formative Questions True or False The work of Watson and Crick solved the mystery of how DNA works as a genetic code.

Chapter 12 Molecular Genetics 12. 2 Formative Questions Which is not an enzyme involved in DNA replication? A. DNA ligase B. DNA polymerase C. hilicase D. RNA primer

Chapter 12 Molecular Genetics 12. 2 Formative Questions During DNA replication, what nucleotide base sequence is synthesized along an original strand that has the sequence TCAAGC? A. AGTTCG B. ATGGCG C. CTGGAT D. GACCTA

Chapter 12 Molecular Genetics 12. 3 Formative Questions Which shows the basic chain of events in all organisms for reading and expressing genes? A. DNA RNA protein B. RNA DNA protein C. m. RNA r. RNA t. RNA D. RNA processing transcription translation

Chapter 12 Molecular Genetics 12. 3 Formative Questions In the RNA molecule, uracil replaces _______. A. adenine B. cytosine C. purine D. thymine

Chapter 12 Molecular Genetics 12. 3 Formative Questions Which diagram shows messenger RNA (m. RNA)? A. C. B. D.

Chapter 12 Molecular Genetics 12. 3 Formative Questions What characteristic of the m. RNA molecule do scientists not yet understand?

Chapter 12 Molecular Genetics 12. 3 Formative Questions A. intervening sequences in the m. RNA molecule called introns B. the original m. RNA made in the nucleus called the pre-m. RNA C. how the sequence of bases in the m. RNA molecule codes for amino acids D. the function of many adenine nucleotides at the 5′ end called the poly-A tail

Chapter 12 Molecular Genetics 12. 4 Formative Questions Why do eukaryotic cells need a complex control system to regulate the expression of genes?

Chapter 12 Molecular Genetics 12. 4 Formative Questions A. All of an organism’s cells transcribe the same genes. B. Expression of incorrect genes can lead to mutations. C. Certain genes are expressed more frequently than others are. D. Different genes are expressed at different times in an organism’s lifetime.

Chapter 12 Molecular Genetics 12. 4 Formative Questions Which type of gene causes cells to become specialized in structure in function? A. exon B. Hox gene C. intron D. operon

Chapter 12 Molecular Genetics 12. 4 Formative Questions What is an immediate result of a mutation in a gene? A. cancer B. genetic disorder C. nonfunctional enzyme D. amino acid deficiency

Chapter 12 Molecular Genetics 12. 4 Formative Questions Which is the most highly mutagenic? A. chemicals in food B. cigarette smoke C. ultraviolet radiation D. X rays

Chapter 12 Molecular Genetics Chapter Assessment Questions Look at the following figure. Identify the proteins that DNA first coils around.

Chapter 12 Molecular Genetics Chapter Assessment Questions A. chromatin fibers B. chromosomes C. histones D. nucleosome

Chapter 12 Molecular Genetics Chapter Assessment Questions Explain how Hox genes affect an organism. A. They determine size. B. They determine body plan. C. They determine sex. D. They determine of body segments. number

Chapter 12 Molecular Genetics Chapter Assessment Questions Explain the difference between body-cell and sex-cell mutation.

Chapter 12 Molecular Genetics Chapter Assessment Questions Answer: A mutagen in a body cell becomes part of the genetic sequence in that cell and in future daughter cells. The cell may die or simply not perform its normal function. These mutations are not passed on to the next generation. When mutations occur in sex cells, they will be present in every cell of the offspring.

Chapter 12 Molecular Genetics Standardized Test Practice What does this diagram show about the replication of DNA in eukaryotic cells?

Chapter 12 Molecular Genetics Standardized Test Practice A. DNA is replicated only at certain places along the chromosome. B. DNA replication is both semicontinuous and conservative. C. Multiple areas of replication occur along the chromosome at the same time. D. The leading DNA strand is synthesized discontinuously.

Chapter 12 Molecular Genetics Standardized Test Practice What is this process called?

Chapter 12 Molecular Genetics Standardized Test Practice A. m. RNA processing B. protein synthesis C. transcription D. translation

Chapter 12 Molecular Genetics Standardized Test Practice What type of mutation results in this change in the DNA sequence? TTCAGG A. deletion B. frameshift C. insertion D. substitution TTCTGG

Chapter 12 Molecular Genetics Standardized Test Practice How could RNA interference be used to treat diseases such as cancer and diabetes?

Chapter 12 Molecular Genetics Standardized Test Practice A. by activating genes to produce proteins that can overcome the disease B. by interfering with DNA replication in cells affected by the disease C. by preventing the translation of m. RNA into the genes associated with the disease D. by shutting down protein synthesis in the cells of diseased tissues

Chapter 12 Molecular Genetics Standardized Test Practice True or False The structure of a protein can be altered dramatically by the exchange of a single amino acid for another.

Chapter 12 Molecular Genetics Glencoe Biology Transparencies

Chapter 12 Molecular Genetics Image Bank

Chapter 12 Molecular Genetics Image Bank

Chapter 12 Molecular Genetics Vocabulary Section 1 double helix nucleosome

Chapter 12 Molecular Genetics Vocabulary Section 2 semiconservative replication DNA polymerase Okazaki fragment

Chapter 12 Molecular Genetics Vocabulary Section 3 RNA intron messenger RNA ribosomal RNA transfer RNA transcription RNA polymerase codon exon translation

Chapter 12 Molecular Genetics Vocabulary Section 4 gene regulation operon mutation mutagen

Chapter 12 Molecular Genetics Animation § DNA Polymerase § Transcription § Visualizing Transcription and Translation § Lac-Trp Operon