Incomplete/Codominance-not always all or none-incomplete --> intermediate blendEx: flower colorRed flower + white flower = pink flower-codominance --> share both traitsEx: blood typePlieotropy-gene affects more than 1 traitEx: sickle cell anemia & malaria resistanceQuantitative Traits-vary by degreeEx: continuous traitsQualitative Traits-vary by a gradientLinkage-physical association among genes on the same chromosomes-should not sort independently-because they are on the same chromosome-can change by crossing over, but not if they are close togetherSex Linkage-genes are on X or Y chromosomes-crossing over creates parental and recombinant gametes in X chromosomesEx: hemophilia A (x-linked recessive)Hershey & Chase Experiment-determined whether protein or DNA is the genetic material by using virus genes-radioactive DNA was inside the cell-radioactive protein was outsidePrimary Structure-sugar-phosphate backbone-5-carbon sugar-5' --> 3'-Polar molecule-nucleotides held together by phosphodiester bonds-covalent bondsSecondary Structure-double-stranded-anti-parallel to one another-Purines (A & G)-Pyrimidines (C & T)-hydrogen bonds stabilize the secondary structure-bonding between complementary bases causes strands to twist*Watson & Crick double helixDNA Replication-happens in the 5' ---> 3' direction-S Phase of Cell Cycle-takes approx. 10 hours-DNA replicates about 80,000 bases/second-we must copy and distribute the stored info between cells during growth-cell division-conserve it accurately with as few errors as possible-Storage, Copy, Distribute-First, we need a primer-RNA primer-Uracil comes in instead of Thyamine-DNA template, match bases to form complementary strand-unzip H bonds to open the double helix-add single strand by binding proteins-primase ---> primer starts process-leading strand & lagging strand**DNA Polymerase III can only add nucleotides to the 3' end-Leading strand:-continuous-only 1 primer needed-elongates toward replication fork-Lagging strand: -delayed, always happening in fragments-many primers needed-elongates away from replication fork-Okasaki fragments-the top and bottom strands are both leading and laggingHelicase-opens up the strands of DNA-breaks H bonds between the bases-binds at the replication forkOkasaki fragments-sections of double-stranded DNADNA Polymerase-single-strand going in, double-strand going outTopoisomerase-binds ahead of the replication fork-breaks covalent bonds in the sugar-phosphate backbone to keep it from supercoiling DNA Polymerase IDNA Polymerase III-only adds new nucleotides to the 3' endTransmission Genetics vs. Molecular Genetics-Transmission genetics focuses on inheritance patterns based on observable phenotypesoTracking movement of chromosomes through meiosis and fertilization-Molecular genetics focuses on the structure and regulation of genes as they are stored on information moleculesoDNA Synthesis (Replication) -Making complete copies of DNAoTranscription-Copying sections of DNA into RNAoTranslation-Converting RNA into amino acids Overview of DNA Synthesis (Replication)-DNA synthesis is a massive challenge with respect to storage, copying, and accuracy-We hold all the information required to "build" an organism within every cell-We must copy and distribute the stored information between cells during growth - cell division-We must conserve that information content accurately with the fewest possible mistakes during storage, copying, and distribution Proteins Required for DNA Synthesis-HelicaseoCatalyzes breaking of hydrogen bonds between base pairs to open the double helix-Single-strand DNA-binding proteinsoStabilizes single-strand DNA-TopoisomeraseoBreaks and rejoins the DNA double helix to relieve twisting forces caused by the opening of the helix-PrimaseoCatalyzes the synthesis of the RNA primer-DNA Polymerase IIIoExtends the leading strand-Sliding ClampoHolds DNA Polymerase III in place during strand extension-DNA Polymerase IoRemoves the RNA primer and replaces it with DNA-DNA LigaseoCatalyzes the joining of Okazaki fragments into a continuous strand Central Dogma in Cell Context-DNA is found in the nucleus-Protein synthesis takes place in the cytoplasm-DNA ---> RNA ----> Protein The meaning of genotype in classical and molecular genetics-Classical GeneticsoWe don't know details about allelesoWe just know they are passed down and interact in certain ways-Molecular GeneticsoWe know the actual sequence of an alleleoEach different sequence is a different version of the gene (allele)-Many different genetic sequences can lead to the same classical genetics patterns of inheritance-Many mutations are a loss of function and there are lots of sequence changes that lead to loss of function Conceptual Translation-If all the information is stored in DNA, then we should be able to "read" it and predict the amino acid sequence that it codes for-We just need to know some of the "rules"-Following the Central Dogma of information flowoDNA is transcribed to mRNAomRNA is translated to proteins (amino acids)-DNA is transcribed to mRNAoBuild mRNA 5' ----> 3' using complementary basesoStart transcribing with AUG (on mRNA reading 5' ----> 3')oRead to the end of the sequence (for now)-mRNA is translated to proteins (amino acids)oRead mRNA 5' ----> 3' in triplets (codons) beginning with start (AUG)oLook up codons in genetic code tableoFinish with stop codon The Challenges of Transcription-Accurately extract information from DNAoUnzip the double helixoUse complementary base pairings -Uracil instead of Thyamine-Work with a small piece of chromosomeoDetermine which DNA strand to readoDetermine where to start and finish copying-Know when to "express" a geneoImportant for responding to environment, cell specialization, and developmentThe Challenges of Translation-Convert information from one format to anotheroRead nucleotide base order-Generate amino acid sequenceoUse complementary base pairing-mRNA to tRNA-Hold everything together in space and time so that recognition and bonding can occuroNeed to bind to the mRNA correctlyoNeed to get several tRNAs in place at once and catalyze the peptide bondingoNeed to know when to stop translating Prokaryote - Information Flow-In bacteria, transcription and translation are tightly coupledoTranscription happens first, and then translation occursoOccur simultaneously-Translation begins before transcription is even finishedoBecause there is no nucleus or barrier for where the information is held-Coding strand: