BIOL 152 1st EditionExam # 1 Study Guide Lectures: 1 - 6Lecture 1 (January 14)What is the one gene - one polypeptide hypothesis?- This is the best hypothesis, but still isn’t technically true, because it has been recently discoveredthat one gene doesn’t necessarily define one polypeptide, but also codes for certain RNA molecules involved in protein synthesis.Three differences between DNA and RNA:- 1. Double helix in DNA vs. Single stranded in RNA - 2. Thymine is in DNA vs. Uracil takes the place of Thymine in RNA- 3. Deoxyribose structure lacks an oxygen vs. Ribose structure has oxygen Why need an RNA intermediate?- Protects DNA blueprint - Allows copies of protein to be made simultaneously, this makes it more efficient - Many RNA transcripts can be made from one gene Steps of Translation1. InitiationmRNA binds to small subunit tRNA binds to mRNA start codon AUGLarge subunit then binds to the small subunit, finally making a ribosomal site for translation to occur 2. ElongationMoves from the Active site to Polypeptide site, where the chain of polypeptides are formed Then the empty tRNA, that has already translated its codons to a protein moves to the Exit site, where it leaves.3. TerminationStop codon is a release factor that adds water, this begins hydrolysis, which breaks the subunits apart. What direction does the DNA Polymerase move?- DNA polymerase moves 5’ to 3’ direction What are codons?- Codon are series of non-overlapping, three nucleotide ‘words’ that provide the genetic instructions for a polypeptide found in mRNAWhat is the central Dogma?- DNA --- RNA --- Protein Lecture 2 (January 16)Evolution - Scientific theory that explains the origin of earth’s species (biodiversity) by gradual change over time - Descent with modification from common ancestor- Is a principal unifying concept in biologyTheory- Is a comprehensive and well supported statement backed by large amounts of evidence Defining Earth Georges Cuvier: - Used paleontology to define the mechanism of how Earth functions - Stated the theory of Catastophism, which states that the Earth had been affected in the past by violent events that led to extinctions and producing adaptive radiation.James Hutton: - Used geology to define the mechanism of how Earth functions- Stated the theory of Gadualism, the cumulative effect of slow but continuous processes that have produced earth’s geologic formationsCharles Lyell: - Stated the theory of Uniformitarianism, that same geologic processes that happened in the pastare happening today at the same rate- Darwin agreed and realized that if true, the Earth was older than 6,000 years old, which many thought it was during Darwin’s time Theory of Evolution Jean-Baptiste Lamarck:- Stated that evolutionary change is based upon two principles:o Use and disuse o Inheritance of acquired characteristics Charles Darwin:- Went aboard the HMS Beagle- Noticed how geologic change can be explained using fossil record- Observed taxonomy that showed continental affinities and also showed similarities between extinct and living forms in the same locale- Observed unique species groups on Galapagos Islands that were Endemic- Observed the adaptation of organisms to the environment and the origin of new species Charles Darwin’s Theory of Evolution - Descent with Modificationo All organisms are related through descent from a common ancestor that lived in the remote pasto Over time, descendants have accumulated modifications that allow them to survive and reproduce in specific habitatsSummary of Natural Selection 1. Individuals do not evolve, only populations do2. Can only act on heritable traits3. Environmental factors vary in space and timeEvolution and Cancer 1. Variation (due to mutations)2. Differential birth and death rates 3. Heredity Overview of Observations of Evolution 1. Direct Observations2. Homologies 3. Fossil Record Lecture 3 (January 23)What is microevolution?- Microevolution = change in genetic makeup of a population from generation to generationDefine species- Species - a group of populations whose individuals have the potential to interbreed and producefertile offspring in natureWhy Natural Selection cannot Fashion ‘perfect’ Organisms1. Can only act on existing variation 2. Limited by historical constraints 3. Adaptations are compromises4. Chance, natural selection, and environment interactSelection alters the frequency of alleles:a. When only one extreme of alleles survive - Directionalb. Centered around a mean, where only the intermediates survive - Stabilizingc. When the intermediates survive and the extreme alleles can’t successfully reproduce - DisruptiveSexual SelectionIndividuals in a population (typically males) differ in their ability to attract mates- Non-random mating- Sexual dimorphism- Intrasexual – direct competition of males for female- Intersexual – the female chooses the mate How is variation maintained?- The diploid status of chromosomes allow recessive alleles to persist in population- Heterozygote advantage - individuals who are heterozygous at a gene sometimes have higher fitness2 types of Genetic Drif- Bottleneck Effect- Founder EffectWhat are 4 processes that change the allele frequencies in a population?1. Mutation 2. Gene Flow – brings new alleles or changes existing alleles3. Genetic Drif – affects small populations (frequencies change randomly) 4. SelectionHardy-Weinberg Principle - Frequencies of alleles and genotypes in a population remain constant from generation to generation provided that only Mendelian segregation and recombination of alleles are at work Hardy-Weinberg Assumptions- 1. No natural selection - 2. No gene flow - 3. Random mating- 4. No mutations- 5. Large populationsLecture 4 (January 24)Nucleic Acids - store and transmit hereditary informationNitrogenous bases are either:- Pyrimidines o cytosineo thymine (DNA)o uracil (RNA) - Purines o adenineo guanineRNA is single-strandedDNA is double- stranded – two polynucleotides spiral around an imaginary axis forming a double helixThree hypotheses for how replication occurred1. Conservative - Parent strands unwind and parents strands come together and daughter strands are formed2. Semiconservative - Parent strand unwind and each function as a template for synthesis of a new complementary strand. 3. Dispersive - mixture of old and new strands How does antiparallel structure affect replication?- Polymerases add nucleotides only to 3¢ end- 5 prime to 3