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
DNA stands deoxyribonucleic acid Section 1 Molecular Genetics DNA: The Genetic Material What is DNA? DNA stands deoxyribonucleic acid DNA is a molecule that encodes the genetic instructions used in the development and functioning of all known living organisms and many viruses What would the DNA of a building be? Blueprints
Genetic info. stored in DNA codes for proteins Section 1 Molecular Genetics DNA: The Genetic Material What is DNA? Genetic info. stored in DNA codes for proteins Genes are segments of DNA DNA is a nucleic acid Proteins, carbohydrates and nucleic acids compose the three major macromolecules essential for all known forms of life
The pairs of nitrogen bases form the steps. Section 1 Molecular Genetics DNA: The Genetic Material DNA Structure DNA is called a double helix and often is compared to a twisted ladder. Rails of the ladder are represented by the alternating: deoxyribose sugar and phosphate. The pairs of nitrogen bases form the steps.
Section 1 Molecular Genetics DNA: The Genetic Material DNA Structure
There are 4 nitrogen bases: cytosine (C) guanine (G) thymine(T) Section 1 Molecular Genetics DNA: The Genetic Material Nitrogen bases There are 4 nitrogen bases: cytosine (C) guanine (G) thymine(T) adenine(A) The four bases pair up to make the “steps” on the “ladder” C-G, A-T
DNA: The Genetic Material Section 1 Molecular Genetics 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′.
DNA: The Genetic Material Section 1 Molecular Genetics 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.
Section 1 Molecular Genetics DNA: The Genetic Material Griffith Performed the first major experiment that led to the discovery of DNA as the genetic material
Concluded that when the S cells were killed, DNA was released Section 1 Molecular Genetics 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.
Used radioactive labeling to trace the DNA and protein Section 1 Molecular Genetics DNA: The Genetic Material Hershey and Chase 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
DNA: The Genetic Material Section 1 Molecular Genetics DNA: The Genetic Material DNA Structure Nucleotides Consist of a five-carbon sugar, a phosphate group, and a nitrogenous base
Chargaff’s rule: C = G and T = A Section 1 Molecular Genetics DNA: The Genetic Material Chargaff Chargaff’s rule: C = G and T = A
X-ray diffraction data helped solve the structure of DNA Section 1 Molecular Genetics DNA: The Genetic Material X-ray Diffraction X-ray diffraction data helped solve the structure of DNA Indicated that DNA was a double helix
two outside strands consist of alternating deoxyribose and phosphate Section 1 Molecular Genetics 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
Semiconservative Replication Section 2 Molecular Genetics 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.
Section 2 Molecular Genetics 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.
Section 2 Molecular Genetics 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.
Section 2 Molecular Genetics Replication of DNA One strand is called the leading strand and 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.
DNA ligase links the two sections. Molecular Genetics Replication of DNA Joining DNA polymerase removes the RNA primer and fills in the place with DNA nucleotides. DNA ligase links the two sections.
Comparing DNA Replication in Eukaryotes and Prokaryotes Section 2 Molecular Genetics 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.
Section 3 Molecular Genetics DNA, RNA, and Protein Central Dogma: an explanation of the flow of genetic information within a biological system
Contains the sugar ribose and the base uracil instead of thymine Section 3 Molecular Genetics DNA, RNA, and Protein RNA- Ribonucleic acid Perform multiple important roles in the coding, decoding, regulation, and expression of genes. Contains the sugar ribose and the base uracil instead of thymine Usually is single stranded
Associates with proteins to form ribosomes in the cytoplasm Section 3 Molecular Genetics DNA, RNA, and Protein 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
DNA is unzipped in the nucleus and RNA Section 3 Molecular Genetics DNA, RNA, and Protein Transcription Through transcription, the DNA code is transferred to mRNA in the nucleus. DNA is unzipped in the nucleus and RNA polymerase binds to a specific section where an mRNA will be synthesized.
The three-base code in DNA or mRNA is called a codon. Section 3 Molecular Genetics DNA, RNA, and Protein 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.
DNA, RNA, and Protein Translation Section 3 Molecular Genetics DNA, RNA, and Protein Translation Based off of the codon RNA is converted to amino acids that are strung together to make proteins. RNAProtiens
Section 3 Molecular Genetics DNA, RNA, and Protein
Section 3 Molecular Genetics 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.
A permanent change that occurs in a cell’s DNA is called a mutation. Section 4 Molecular Genetics Gene Regulation and Mutation Mutations A permanent change that occurs in a cell’s DNA is called a mutation. Types of mutations Point mutation Frame shift Duplication
Involves a chemical change in one base pair Section 4 Molecular Genetics Gene Regulation and Mutation Point mutations Involves a chemical change in one base pair Substitutions Missense – codes for the wrong amino acid Nonsense - change the code for an amino acid to a stop codon. Leads to improper function of proteins
Insertion – inserts the wrong base into the three base sequence Section 4 Molecular Genetics Gene Regulation and Mutation Frameshift Changes the multiples of three and cause the “frame” (codon) to shift right or left. Insertion – inserts the wrong base into the three base sequence Deletion - Removes a base from the three base sequence
Gene Regulation and Mutation Section 4 Molecular Genetics Gene Regulation and Mutation
Can occur spontaneously Section 4 Molecular Genetics 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.
Body-cell v. Sex-cell Mutation Section 4 Molecular Genetics Gene Regulation and Mutation Body-cell v. Sex-cell Mutation Somatic cell (normal cells) 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.
Section 2 Genetics and Biotechnology DNA Technology Genetic Engineering Technology that involves manipulating the DNA of one organism in order to insert the DNA of another organism
Genetically engineered organisms are used Section 2 Genetics and Biotechnology DNA Technology Genetically engineered organisms are used to study the expression of a particular gene. to investigate cellular processes. to study the development of a certain disease. Genetically engineered bollworm to select traits that might be beneficial to humans.
Mice, fruit flies, and the roundworm Section 2 Genetics and Biotechnology DNA Technology Transgenic Animals Scientists produce most transgenic animals in laboratories for biological research. Mice, fruit flies, and the roundworm
Genetically engineered cotton resists insect infestation of the bolls. Section 2 Genetics and Biotechnology DNA Technology Transgenic Plants Genetically engineered cotton resists insect infestation of the bolls. Sweet-potato plants are resistant to a virus that could kill most of the African harvest. Rice plants with increased iron and vitamins could decrease malnutrition.
Section 2 Genetics and Biotechnology DNA Technology Restriction enzymes recognize and bind to specific DNA sequences and cleave the DNA within the sequence. Scientists use restriction enzymes as powerful tools for isolating specific genes or regions of the genome.
Section 2 Genetics and Biotechnology DNA Technology The newly generated DNA molecule with DNA from different sources is called recombinant DNA.
An organism’s genome is the total DNA in the nucleus of each cell. Section 2 Genetics and Biotechnology DNA Technology DNA Tools An organism’s genome is the total DNA in the nucleus of each cell. DNA tools can be used to manipulate DNA and to isolate genes from the rest of the genome.
The Human Genome Project Section 3 Genetics and Biotechnology The Human Genome The Human Genome Project The goal of the Human Genome Project (HGP) was to determine the sequence of the approximately three billion nucleotides that make up human DNA and to identify all of the approximately 20,000–25,000 human genes.
Section 2 Genetics and Biotechnology DNA Technology An electric current is used to separate DNA fragments according to the size of the fragments in a process called gel electrophoresis.
Gel electrophoresis Used to: To get a DNA Fingerprint for forensics To get a DNA fingerprint for paternity testing To get a DNA fingerprint so that you can look for evolutionary relationships among organisms To check a PCR reaction. To test for genes associated with a particular disease.
Section 2 Genetics and Biotechnology DNA Technology A technique called the polymerase chain reaction (PCR) can be used to make millions of copies of a specific region of a DNA fragment.
Section 2 Genetics and Biotechnology DNA Technology