Biology Chapter 25-28 PDF

Chapter 25 Origin Diversity of Life Geological time is divided into 4 eon eras periods epoch camabrian 500milyrsago explosion fossilrecords carboniferous fossi f...

Chapter 25 Origin Diversity of Life Geological time is divided into 4 eon eras periods epoch camabrian 500milyrsago explosion fossilrecords carboniferous fossi fuels No life until 3.6 3.8 Bil yrs prokaryotes 2 7 Bil yrs later eukaryote traces changes in Earth in Geo time Co2 Levels shifted affected temp Increastweathering converted silicate rock to soll continents moved over geo time te ch tonic plates supercontinents panged evolutionaryline Life emerged in Archean eon Cambrianperiod showeddiversification of multicellular organisms Early organicmolecules How first molecules formed is unknown organic  CH 25 Earths Earths atmosphere carbon dioxide Co2 Nitrogen gas N2 Water vapor H2O Hydrogen gas H2 Miller urey experiment 7 SO 4 key steps 7 monomer 2 polymer 2Deyasten 3 protocell 4 self replicating ribozymes Emergence of metabolic pathways Primitive organisms were autotrophic built whattheyneeded RNAImay have been first genetic material conditions on early Earth High temps fossil evidence of life Evidence of life during Archae in the form of microfossils is hard to find learn about lsipgsded.at microfossils 3.5 Bil yrs old resemble todaysprokaryotes  CH 25 stromatolites mats of deposits Icteria cells that trap mineral Earthschanging system climate temp water availability Mass extinction influencing evolution Deductive reasoning General statement inductive reasoning patterns trends compartmentalization of cells 3 Domains 1 Eukaryotic organelles membrane etc Roc 1 Plantae Bacteria Archaea No compartmentalization IfAll have Kingdoms compartmentalization  one organismengulfed CH 25 another through endocytosis Nosymbiosis a origin of Eukaryotes Mitochondria chloroplasts entered early eukaryotic cells by endosymbiosis Chloroplasts are derived from cyanobacteria 7 comet Tanya own DNA Ribosomes double memplate MitochondriarchloropMI Endosymbiosis Endocytosis Ribosomes match Archean Ribosome sizes on their own protista Plantae thyghtfet replicate came from cyobactera Chloroplast Anamina protista planta only protista Plantae have both  CH 25 Multicellularity leads to cell specialization 1 Unicellular body plan very successful unicellular prokaryotes eukaryotes be everything is Multicellularity allowed organisms to deal w environment in more waysthroughdifferentiation sexual reproduction increases geneticdiversity Meiosis crossing over Random Firtilization genetic First eukaryotes were probs haploid Staffing Rapid diversification occured during Cambrian All life began in water Cambrian explosion Diversity rapidexpansion of life First multicellularanimals 50 milyrs after Cambrian explosion Majorinnovations allowed for moving onto land plants then animals go to land after Cambrian radiation ozone layer water protects organisms underwater from UV light movement from water to land required innovations to prevent desication to maintain water  CH 26 Viruses Viruses are not considered living Cannot reproduce on their own must have a host cell Cannot utilize energy on their own Nature of viruses All viruses have same basic structure Lead core surrounded by protein No cytoplasm not a cell Nucleic acid can be DNA or RNA circular or linear Single or double stranded classified by genome RNA Viruses DNA viruses or retroviruses Viral hosts obligateintracellularparasites in every kind of organisminvestigated Hostrange types of organisms infected Eachtype of viruses has a limited hostrange Tissuetropism inside a host the virusmayonly infect certaintissue can remaindormant or latent for years Chicken pox can reemerge as shingles more viruses can exist than kinds of organisms Lysogenic Lytic 1 causeshostcell to rupture sleeping in cell temerate 20 25 fE.sihhnotners  CH 26 Viral Genomes 7 Very greatly in bothtype of nucleic acid of strands most RNA viruses are single strande Replicated in the host cells's cytoplasm Replication in cytosol is error prone highrates of mutation difficult targets for immunesystem vaccines drugs Viral Genomes 2 RNA viruses positive strand virus viral RNA serves as mRNA Negative strands virus genome is complementaryto viral MRNA Retovirus employreverse transcriptase to reverse transcribe Vival RNA Into DNA most viruses are doublestranded replicated in nucleus of eukaryotic host cell Human immunodeficiency virus some people are resistant to Hiv infection exposed repeatedly never become others become Hiv without developing Alds others have little resistance progressrapidly from infection to death Alds is a diseas HIV is a virus  CH 26 Hiv will cause Alds once it turns lytic Emerging virus viruses that originate in one organism then passes to another causesdisease considerable threat in the aviation age SARS coronavirus severe acute respiratorysyndrome viruses cancer Viruses can contribute to 15 20 of all human cancers viruses can cause cancer by altering the growth properties of human cells Prions Protienaceous infectious Particles cause transmissable spongiform encephalopathies TSEs Host has normal Prion Proteins Prp misfolded Proteins PrPsc causesnormal Prp to misfold Viroids Tiny naked molecules of circular RNA  CH 27 Prokaryotes The size of prokaryotic cells led to their being Undiscoverable for most of human history History of microbiology 2 Antony Von Leeuwenhook was first to observe accurately describe microbial life History of microbiology 3 Koch's postulates Koch studied anthrax proposed 4 posulates to prove a causual relationship between a microorganism disease 1 Themicroorganism must be present in every case of the disease absent from healthy individuals 2 The putative causative agent must be isolated grown in pure culture 3 Tesamediseasemustresult when the cultured microorganism is used to infect a healthy host 4 The same microorganism must be isolated again from the diseased host prokaryotic Diversity Fall into 2 Domains Bacteria Kingdom Archaea characteristics of prokaryotes 7 unicellularity most are single celled cell size varies most less than 7 mm in diameter Nucleoid Chromosome is single circular doublestranded DNA  CH 27 found in the nucleoid region of cell often have plasmids cell division most divide by binaryfissionT Genetic recombination Exchange material through horizontal gene transfer not a form of reproduction internal compartmentalization No membrane bounded organelles No internal compartmentalization Plasma membrane can be extensively infolded Flagella simple in structure DIFF From eukaryotic flagella metabolic diversity oxygenic anoxygenicphotosynthesis Chemolithotrophic Bacteria Archea differ fundamentally Differ in 4 key areas plasma membranes Cell walls DNA replication Gene expression  CH 27 Plasma membrane All prokaryoteshavea plasma membrane Archean membranes have an ETHer linkage Bacteria eukaryotes have Ester linkage cell wall All prokaryotes have a cell wall Bacteria have peptidoglycan Archaea LACK peptidogican DNA replication Archaen DNA rep is similar to eukaryotes Gene expression Archaeal transcription translation similar to eukaryotes  CH 27 Early Classification Characteristics 1 nonphotsynthetic photosynthetic or 2 me or nonmotile 3 unicellular colonyforming or filamentous 4 formation ofspores or division by transverse binary fission 5 importance as human pathogens or not prokaryotic cell structure 3 basic shapes Bacillus Rod shape 00 coccus spherical 00 sprillum Helical shaped 556 staff Erattoooo cluster 8 Staphylo cell wall peptidoglycan forms a rigid network Maintainsshape withstands hypertonic environments Archaen havesimilarmolecule Gram stain bacteria have a thicker peptidoglycan wall purple Blue color less peptidoglycan Pink Red color Second outer membrane with lipopolysaccharide flagella Slender rigid helical spin like propeller Pill short hairline gram bacteria AidIn Gtatachment  CH 27 Endospores form a thick wall around genome a small portion when exposed to environmental stress highly resistant to env stress especially heat Bacteria causing tetanus botulism anthrax organization of prokaryotes Nucleoid region singular circular chromosome May contain plasmids Ribosomes smaller than eukaryotes ribos Differ in protein RNA content Targeted by some antibiotics prokaryotic Genetics Do not reproducesexually primary method is binary fission 3 types of horizontalgene transfer conjugation cell to cell contact Transduction Transformationbyfrom the environment viruses Also observed in archaea conjugation plasmids may encode fns not necessary to the organism but may provide selective advantage Ft has plasmid F cell do not  CH 27 Ft cells produces F pilus that connects to F cell Transfer of F plasmid occurs through conjugation bridge F plasmid copied through rollingcycle Replication The end result is 2 Ft cells F plasmid recombination F plasmid can integrate into bacteria chromosome similar to crossing over m eukaryotes Homologous recomb Her cell high frequency of recomb replicated everytime host divides F plasmid can excise itself by reversing the integration process Transduction General transduction virtuallyany gene can be transferred occurs by accidents in lytic cycle Viruses package bacterial DNA transfer it in subsequent infection  CH 27 specialized transduction occurs by accidents in lysogenic cycle imprecise extision of prophageDNA Phage carry phagetchromosomal genes Natural Transformation happens in many bacterial species DNA that is released from a dead cell is pickedup by another live cell protein involved in NT encoded bacterial chromosome by Not an accidant Antibiotic Resistance R resistant plasmids Encode antibiotic resistantgenes Genes from pathogenic species transferred by plasmids or transduction Encode genes for pathogenic traits CRISPR screens of prokaryotic genomes revealed repeated sequences with spacer regions Adaptive immunity to viral infection Beneficial prokaryotes Decomposers release a dead organisms atoms to the environment Nitrogen fixers reduce Nz to NHz  CH 27 symbiosis ecological relationship between diff species that live in direct contact w each other Mutualism commensalism parasitism Bacteria in genetic engineering bioremediation In genetic engineering produces various chemicals insulin Bioremediation Removes pollutants from water air so'll