Each of the chromosomes has thousands of different genesPurposes of studying geneticsStudy of genetics explainsHow family resemblance ariseHow the characteristics of populations ariseHow organisms function at the molecular and cellular levelsTwo different fields of studyInheritancePopulation geneticsWhy do some children inherit the disease Sickle-Celled anemia and others don’t?Its inheritanceWhy is sickle-celled anemia more common in African-Americans thn in Caucasians ?This is talking about different populationsToday we knowEach trait is controlled by genesGenes occur in different forms called allelesSome alleles are dominant while others are recessive.For each trait, you inherit 1 allele from each parentYour combination of alleles (genotype) determines which form of a trait you will express (phenotype)Having 5 Fingers is recessive, having 6 is dominant.Genetics of Human Blood TypesHow many phenotypes are there?4O, A, AB, BHow many alleles are present in an individual?2 alleles for blood typeHow many different alleles are present in the human population?A, B, OHow many genotypes are possible?A Ao, B Bo, AB, O6CoDominance, in which the heterozygote displays characteristics of both homozygotes.There are more than 9,000 Human traits are determined by a single geneBUT: most traits are more complexPhenotype traits are influenced byMany genes— polygenic TraitEx. Skin Color: 1 Pigment, produced by 3 genes, 6 different allelesSame genotype, but phenotype differs based on environmental factors (during fetal development in this case)Is your body making any new cells right now? What kind?Yes, Skin cells, hair cellsAre certain types of cells replaced faster? What might be examples?Blood cells, skin cells, stomach lining cellsAre certain types of cells never replaced or slowly replaced? What might be examples?Brain cellsCells have regular cycles of growth and divisionThe cell cycle is an ordered sequence of events in the lifetime of a cellThere are two broad phases:Interphase90% of cells lifetimeNormal Cell functionMitotic phaseActive cell divisionThe cell cycleHealthy cells only enter the mitotic phase if duplication is needed.Most of a cells lifetime is spent in interphaseDuring this, the cellPerforms its normal functionsDuring mitotic phase, the cellUndergoes active division (mitosis)Splits into two offspring cells (cytokinesis)The result of the mitotic phase is two genetically identical offspringMitosis— nucleus dividesAsexual cell reproduction in prokaryotic cellsGoes from one cell to having two, chromosome divides.Called binary fissionRequires DNA replicationSynthesis of more cytoplasmSimpler than in eukaryotic cellsCell division in plant cells leads to growth or vegetative reproductionNo cleavage furrow in rigid plant cell; instead build new plasma membrane and cell wall down the middle of plant cell to separate from inside out.Aspen stand of clones means asexual reproduction predominates.Asexual reproduction only needs one parentOne parent produces genetically identical offspringThere is no sperm or egg involved.Cell division in animal cells leas to growth of organismCleavage furrow in cell surfaceCell multiplication unrestrained = cancerStopping the uncontrolled cell division can stop cancer growth.TelomeresEvery time a cell divides, the telomere gets shorter. After a critical number of cell division, functional DNA is lost which means almost certain death for the cell.Many chemotherapy drugs are used to treat cancer by killing cells undergoing mitosisWhat side effects have you heard of related to chemotherapy treatment for cancer?With your understanding of mitosis, can you explain some of the side effects of chemotherapy.Penicillin works by stopping the reproduction of a cellIN class writing: Is sex necessary?What is sex?The recombination or exchange of DNADo bugs have sex?Yes.Do trees have sex?Yes. They advertise they are ready to reproduce by showing flowers.Do bacteria have sex?Bacteria can exchange genes, but not during reproduction.Bacteria can have sex, but there reproduction is asexual.Can organisms reproduce without sex?Yes. Sex is not necessary for reproduction of some organisms.Flatworm, StarfishMeiosis: Reducing the Genome by halfEach chromosome in a homologous pair replicates to form a sister chromatidIn the first division of meiosis, the homologous pairs separate.In the second division of meiosis, the sister chromatids separate. This results in four haploid cells, of which two contain a single copy of one of the original chromosomes and the other two contain a single copy of the other chromosome.Too many or two few sex chromosomesTurner SyndromeShort heightWeb of skin between neck and shouldersUnderdeveloped ovaries, often sterile,Some learning difficultiesKlinefelter syndromeUnderdeveloped testesLower testosterone levels, usually infertileDevelopment of some female featuresLong limbs and slightly taller than averageSuper MalesTaller than averageModerate to severe acneIntelligence may be slightly lower than averageMetafemalesMay be sterileNo obvious physical or mental problemsSexual reproduction takes two parentsTwo parents reproduce genetic offspringThe definition of male vs. femaleFemales produce the larger gameteMales produce the smaller, more motile gamete.Reproduction and sex is influenced by the environment in many species, not just by the genetics.Sexual reproduction leads to variationThree major processes mean variation is the normal for sexual reproduction:Independent assortmentRandom fertilizationCrossing over.Each gamete is genetically uniqueThe point of sexual reproduction is hoping that your children will be better adapted to survive than you are.Meiosis is not the same as mitosis!!!E is for sex. I is all by yourself.How to studyGoal: explain the relationships between termsThese are concepts.Binary Fission is a type of Asexual reproduction.Study like you’re studying for a short answer test.DNA controls functions of the cell using RNA as “employees”Transcription: Making RNA from DNA (like training your employees)Translation: Making proteins from RNA.If RNA only makes proteins, how do other biological molecules get made?The proteins direct the synthesis of the other molecules.AnalogyDNALike superintendent of schoolsRNALike the school principalsProteinsLike the classroom teachersCarbs, Lipids, Nucleic AcidLike the studentsGene expression, the production of proteins, is regulated in several ways.Gene regulation is the process of turning genes on