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
What is DNA? link Where is it found? Why study it? Where do you see or hear it mentioned?
12-1 DNA Griffith’s experiment
Avery discovered DNA caused transformation. Chapter 12 Molecular Genetics 12.1 DNA: The Genetic Material Avery discovered DNA caused transformation. 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.
Used radioactive labeling to trace the DNA and protein Chapter 12 Molecular Genetics Hershey and Chase link Used radioactive labeling 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
DNA Structure Nucleotides Chapter 12 Molecular Genetics DNA Structure Nucleotides Consist of a five-carbon sugar, a phosphate group, and a nitrogenous base
Chargaff’s rule: C = G and T = A Chapter 12 Molecular Genetics 12.1 DNA: The Genetic Material Chargaff Chargaff’s rule: C = G and T = A
X-ray diffraction data helped solve the structure of DNA- Franklin Chapter 12 Molecular Genetics 12.1 DNA: The Genetic Material X-ray Diffraction X-ray diffraction data helped solve the structure of DNA- Franklin Indicated that DNA was a double helix
two outside strands consist of alternating deoxyribose and phosphate 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 two outside strands consist of alternating deoxyribose and phosphate cytosine and guanine bases pair to each other by three hydrogen bonds thymine and adenine bases pair to each other by two hydrogen bonds
DNA often is compared to a twisted ladder (double helix). Chapter 12 Molecular Genetics 12.1 DNA: The Genetic Material DNA Structure DNA often is compared to a twisted ladder (double helix). Rails of the ladder are represented by the alternating deoxyribose (sugar) and phosphate. The pairs of bases (cytosine–guanine or thymine–adenine) form the steps.
12.1 DNA: The Genetic Material Chapter 12 Molecular Genetics 12.1 DNA: The Genetic Material
12.1 DNA: The Genetic Material 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.
Chapter 12 Molecular Genetics 12.2 Replication of DNA 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 link Base pairing DNA polymerase continues adding appropriate nucleotides to the chain by adding to the new DNA strand.
Chapter 12 Molecular Genetics
Comparing DNA Replication in Eukaryotes and Prokaryotes 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.
Central Dogma DNA RNA Protein Chapter 12 Molecular Genetics 12.3 DNA, RNA, and Protein Central Dogma DNA RNA Protein RNA – different from DNA 1. Contains the sugar ribose 2. Contains base uracil not thymine 3. single stranded
Associates with proteins to form ribosomes in the cytoplasm 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
Chapter 12 Molecular Genetics
Chapter 12 Molecular Genetics
RNA will move to the cytoplasm. Chapter 12 Molecular Genetics Transcription link RNA is made from the DNA code (in nucleus). RNA will move to the cytoplasm. DNA is unzipped in the nucleus and RNA polymerase binds to a specific section where an mRNA will be synthesized.
Chapter 12 Molecular Genetics
The three-base code in DNA or mRNA is called a codon. Ex. AGC CCU AAC 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. Ex. AGC CCU AAC
Translation- the mRNA code is read. Chapter 12 Molecular Genetics Translation- the mRNA code is read. 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.
Chapter 12 Molecular Genetics Visualizing Transcription and Translation
Ex: Do babies go through puberty? Explain. Chapter 12 Molecular Genetics 12.4 Gene Regulation and Mutation Gene Regulation Ability of an organism to control which genes are transcribed in response to the environment (turned on and off). Ex: Do babies go through puberty? Explain. Do birds nest in the fall? Explain. Do you make proteins if you don’t need them? An operon is a section of DNA that contains the genes for the proteins needed for a specific function.
Chapter 12 Molecular Genetics Hox Genes Hox genes are responsible for the general body pattern of most animals.
A permanent change that occurs in a cell’s DNA is called a mutation. Chapter 12 Molecular Genetics Mutations A permanent change that occurs in a cell’s DNA is called a mutation. Types of mutations Point mutation –only one base is wrong Insertion- extra base Deletion – missing a base Substitution –different base Duplication – repeated bases
Can occur spontaneously (accidental) Chapter 12 Molecular Genetics 12.4 Gene Regulation and Mutation Causes of Mutation Can occur spontaneously (accidental) Chemicals and radiation also can damage DNA. High-energy forms of radiation, such as X rays and gamma rays, are highly mutagenic.
Body-cell v. Sex-cell Mutation Chapter 12 Molecular Genetics Can mutations be passed on? Are all mutations bad? Body-cell v. Sex-cell Mutation Somatic (body cell) mutations are not passed on to the next generation. Mutations that occur in sex cells are passed on to the organism’s offspring and will be present in every cell of the offspring. Different DNADifferent RNADifferent AADifferent protein
12.4 Gene Regulation and Mutation Chapter 12 Molecular Genetics 12.4 Gene Regulation and Mutation
Chapter Resource Menu Chapter Diagnostic Questions 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.
Which scientist(s) definitively proved Chapter 12 Molecular Genetics Chapter Diagnostic Questions Which scientist(s) definitively proved that DNA transfers genetic material? Watson and Crick Mendel Hershey and Chase Avery
Name the small segments of the lagging DNA strand. Chapter 12 Molecular Genetics Chapter Diagnostic Questions Name the small segments of the lagging DNA strand. ligase Okazaki fragments polymerase helicase
It contains the sugar ribose. It contains the base uracil. Chapter 12 Molecular Genetics Chapter Diagnostic Questions Which is not true of RNA? It contains the sugar ribose. It contains the base uracil. It is single-stranded. It contains a phosphate.
The experiments of Avery, Hershey and Chapter 12 Molecular Genetics 12.1 Formative Questions The experiments of Avery, Hershey and Chase provided evidence that the carrier of genetic information is _______. carbohydrate DNA lipid protein
What is the base-pairing rule for purines Chapter 12 Molecular Genetics 12.1 Formative Questions What is the base-pairing rule for purines and pyrimidines in the DNA molecule? A—G and C—T A—T and C—G C—A and G—T C—U and A—G
What are chromosomes composed of? Chapter 12 Molecular Genetics 12.1 Formative Questions What are chromosomes composed of? chromatin and histones DNA and protein DNA and lipids protein and centromeres
The work of Watson and Crick solved the mystery of how DNA works as a 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.
Which is not an enzyme involved in DNA replication? Chapter 12 Molecular Genetics 12.2 Formative Questions Which is not an enzyme involved in DNA replication? DNA ligase DNA polymerase hilicase RNA primer
During DNA replication, what nucleotide 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? AGTTCG ATGGCG CTGGAT GACCTA
Which shows the basic chain of events Chapter 12 Molecular Genetics 12.3 Formative Questions Which shows the basic chain of events in all organisms for reading and expressing genes? DNA RNA protein RNA DNA protein mRNA rRNA tRNA RNA processing transcription translation
In the RNA molecule, uracil replaces _______. Chapter 12 Molecular Genetics 12.3 Formative Questions In the RNA molecule, uracil replaces _______. adenine cytosine purine thymine
Which diagram shows messenger RNA (mRNA)? Chapter 12 Molecular Genetics 12.3 Formative Questions Which diagram shows messenger RNA (mRNA)? A. C. B. D.
What characteristic of the mRNA molecule Chapter 12 Molecular Genetics 12.3 Formative Questions What characteristic of the mRNA molecule do scientists not yet understand?
intervening sequences in the mRNA molecule Chapter 12 Molecular Genetics 12.3 Formative Questions intervening sequences in the mRNA molecule called introns the original mRNA made in the nucleus called the pre-mRNA how the sequence of bases in the mRNA molecule codes for amino acids the function of many adenine nucleotides at the 5′ end called the poly-A tail
Why do eukaryotic cells need a complex Chapter 12 Molecular Genetics 12.4 Formative Questions Why do eukaryotic cells need a complex control system to regulate the expression of genes?
All of an organism’s cells transcribe the same Chapter 12 Molecular Genetics 12.4 Formative Questions All of an organism’s cells transcribe the same genes. Expression of incorrect genes can lead to mutations. Certain genes are expressed more frequently than others are. Different genes are expressed at different times in an organism’s lifetime.
Which type of gene causes cells to become specialized in structure in Chapter 12 Molecular Genetics 12.4 Formative Questions Which type of gene causes cells to become specialized in structure in function? exon Hox gene intron operon
What is an immediate result of a mutation in a gene? Chapter 12 Molecular Genetics 12.4 Formative Questions What is an immediate result of a mutation in a gene? cancer genetic disorder nonfunctional enzyme amino acid deficiency
Which is the most highly mutagenic? Chapter 12 Molecular Genetics 12.4 Formative Questions Which is the most highly mutagenic? chemicals in food cigarette smoke ultraviolet radiation X rays
Look at the following figure. Identify the Chapter 12 Molecular Genetics Chapter Assessment Questions Look at the following figure. Identify the proteins that DNA first coils around.
chromatin fibers chromosomes histones nucleosome Chapter 12 Molecular Genetics Chapter Assessment Questions chromatin fibers chromosomes histones nucleosome
Explain how Hox genes affect an organism. Chapter 12 Molecular Genetics Chapter Assessment Questions Explain how Hox genes affect an organism. They determine size. They determine body plan. They determine sex. They determine number of body segments.
Explain the difference between body-cell and sex-cell mutation. Chapter 12 Molecular Genetics Chapter Assessment Questions Explain the difference between body-cell and sex-cell mutation.
Answer: A mutagen in a body cell becomes Chapter 12 Molecular Genetics Chapter Assessment Questions Answer: A mutagen in a body cell becomes part of the 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.
What does this diagram show about the replication of DNA Chapter 12 Molecular Genetics Standardized Test Practice What does this diagram show about the replication of DNA in eukaryotic cells?
DNA is replicated only at certain places along Chapter 12 Molecular Genetics Standardized Test Practice DNA is replicated only at certain places along the chromosome. DNA replication is both semicontinuous and conservative. Multiple areas of replication occur along the chromosome at the same time. The leading DNA strand is synthesized discontinuously.
What is this process called? Chapter 12 Molecular Genetics Standardized Test Practice What is this process called?
mRNA processing protein synthesis transcription translation Chapter 12 Molecular Genetics Standardized Test Practice mRNA processing protein synthesis transcription translation
TTCAGG TTCTGG What type of mutation results in this change Chapter 12 Molecular Genetics Standardized Test Practice What type of mutation results in this change in the DNA sequence? TTCAGG TTCTGG deletion frameshift insertion substitution
How could RNA interference be used Chapter 12 Molecular Genetics Standardized Test Practice How could RNA interference be used to treat diseases such as cancer and diabetes?
by activating genes to produce proteins that Chapter 12 Molecular Genetics Standardized Test Practice by activating genes to produce proteins that can overcome the disease by interfering with DNA replication in cells affected by the disease by preventing the translation of mRNA into the genes associated with the disease by shutting down protein synthesis in the cells of diseased tissues
The structure of a protein can be altered 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.
Glencoe Biology Transparencies Chapter 12 Molecular Genetics Glencoe Biology Transparencies
Chapter 12 Molecular Genetics Image Bank
Chapter 12 Molecular Genetics Image Bank
Section 1 Vocabulary double helix nucleosome Chapter 12 Molecular Genetics Vocabulary Section 1 double helix nucleosome
Section 2 Vocabulary semiconservative replication DNA polymerase Chapter 12 Molecular Genetics Vocabulary Section 2 semiconservative replication DNA polymerase Okazaki fragment
Section 3 Vocabulary RNA messenger RNA ribosomal RNA transfer RNA Chapter 12 Molecular Genetics Vocabulary Section 3 RNA messenger RNA ribosomal RNA transfer RNA transcription RNA polymerase codon intron exon translation
Section 4 Vocabulary gene regulation operon mutation mutagen Chapter 12 Molecular Genetics Vocabulary Section 4 gene regulation operon mutation mutagen
Visualizing Transcription and Translation Chapter 12 Molecular Genetics Animation DNA Polymerase Transcription Visualizing Transcription and Translation Lac-Trp Operon