BIOL 152 1st Edition Final Exam Study Guide Lectures 1 25 Lecture 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 discovered that 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 Translation 1 Initiation mRNA binds to small subunit tRNA binds to mRNA start codon AUG Large subunit then binds to the small subunit finally making a ribosomal site for translation to occur 2 Elongation Moves 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 Termination Stop 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 mRNA What 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 biology Theory 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 formations Charles Lyell Stated the theory of Uniformitarianism that same geologic processes that happened in the past are 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 Modification o All organisms are related through descent from a common ancestor that lived in the o remote past Over time descendants have accumulated modifications that allow them to survive and reproduce in specific habitats Summary of Natural Selection 1 Individuals do not evolve only populations do 2 Can only act on heritable traits 3 Environmental factors vary in space and time Evolution and Cancer 1 Variation due to mutations 2 Differential birth and death rates 3 Heredity Overview of Observations of Evolution 1 Direct Observations 2 Homologies 3 Fossil Record Lecture 3 January 23 What is microevolution Microevolution change in genetic makeup of a population from generation to generation Define species Species a group of populations whose individuals have the potential to interbreed and produce fertile offspring in nature Why Natural Selection cannot Fashion perfect Organisms 1 Can only act on existing variation 2 Limited by historical constraints 3 Adaptations are compromises 4 Chance natural selection and environment interact Selection alters the frequency of alleles a When only one extreme of alleles survive Directional b Centered around a mean where only the intermediates survive Stabilizing c When the intermediates survive and the extreme alleles can t successfully reproduce Disruptive Sexual Selection Individuals 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 fitness 2 types of Genetic Drif Bottleneck Effect Founder Effect What are 4 processes that change the allele frequencies in a population 1 Mutation 2 Gene Flow brings new alleles or changes existing alleles 3 Genetic Drif affects small populations frequencies change randomly 4 Selection Hardy 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 populations Lecture 4 January 24 Nucleic Acids store and transmit hereditary information Nitrogenous bases are either Pyrimidines o cytosine o thymine DNA o uracil RNA Purines o adenine o guanine RNA is single stranded DNA is double stranded two polynucleotides spiral around an imaginary axis forming a double helix Three hypotheses for how replication occurred 1 Conservative Parent strands unwind and parents strands come together and daughter strands are formed 2 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 prime direction of replication Along the leading DNA polymerase III synthesizes a complementary strand continuously moving toward the replication fork Synthesizing the leading lagging strands Leading