BIOL 102 Exam #2 (9/27/16) Study Guide
BIOL 102 Exam #2 (9/27/16) Study Guide BIO 102
Popular in General Biology
verified elite notetaker
Popular in Department
This 9 page Study Guide was uploaded by Zach Notetaker on Saturday September 24, 2016. The Study Guide belongs to BIO 102 at University of South Carolina taught by Mihaly Czako in Fall 2016. Since its upload, it has received 149 views.
Reviews for BIOL 102 Exam #2 (9/27/16) Study Guide
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 09/24/16
BIOL 102 Exam Study Guide Ch. 25(slides 72+)29 Exam #2 Study Guide Homeotic Genes: determine basic features like where wings and legs will develop on a bird or how a flower’s parts are arranged o Hox genes: class of homeotic genes that provides positional info during animal embryonic development if expressed in WRONG LOCATION body parts can be produces in WRONG LOCATION ex) Monster fruit fly w/ a million eyes Changes in Genes: o New morphological forms likely come from gene duplication that produce new developmental genes o Specific changes in Ubx genes identified that can “turn off” leg development Changes in Gene Regulation: o Changes in morphology likely result from changes in regulation of developmental genes rather than changes in sequence of developmental changes ex) threespine sticklebacks in lakes have fewer spines than their marine relatives gene sequence remains same, but regulation of gene expression is different in 2 groups of fish Evolution is like tinkering new forms arise by slight modification of existing forms Evolutionary Novelties: o Most novel biological structures evolve in many stages from previously existing structures o Complex eyes have evolved from simple photosensitive cells independently many times o Exaptations: structures that evolve in one context but become coopted for different functions o Natural selection can only improve structure in context of current utility Evolutionary Trends: o Extracting single evolutionary progression from fossil record can be misleading o Trends should be examined in broader context o DON’T imply intrinsic drive toward particular phenotype o Similar environment factors = similar adaptations Taxonomy: scientific discipline that classifies and names organisms Systematics: classifies organisms and determines evolutionary relationships Phylogeny: evolutionary history of species or group of related species o Phylogenetic trees show patterns of descent, NOT phenotypic similarity o Phylogenetic trees don’t indicate WHEN a species evolved or how much change occurred in lineage o NOT assumed that taxon evolved from taxon next to it Homoplasies (a homoplasy): analogous structures or molecular sequences that evolved independently Cladistics: groups organisms by common descent o Clade: group of species that includes ancestral species and all its descendants Mono phyletic: a valid clade that consists of the ancestor species and all of its descendants Para phyletic: an invalid clade consisting of an ancestral species and some, but NOT ALL, of the descendants Poly phyletic: an invalid clade including distantly related species but does NOT include their most recent common ancestor Shared ancestral character: character that originated in an ancestor of the taxon Shared derived character: evolutionary novelty unique to a particular clade o character can be both ancestral and derived, depending on context Molecular clock: uses constant rates of evolution in some genes to estimate the absolute time of evolutionary change o calibrated against branches whose dates are known from fossil record o individual genes vary in how clocklike they are Domains: Bacteria, Archaea, Eukarya Kingdoms: Protista, Plantae, Fungi, Monera (prokaryotes), Animalia Horizontal Gene Transfer: movement of genes from one genome to another o tree of life suggests that eukaryotes and archaea more closely related than bacteria o tree of life based largely on rRNA genes; however, some other genes reveal different relationships o key role in evolution of prokaryotes and eukaryotes Prokaryotes found in every possible habitat… Ex) Utah’s Great Salt Lake pink color comes from living prokaryotes o Thrive almost everywhere o Mostly microscopic o LOTS OF THEM o Divided into two domains: bacteria and archaea Earth’s early organisms were likely prokaryotes o unicellular, but some form special colonies o variety of shapes o common shapes: spheres (coccus/cocci), rods (bacillus, bacilli), and spirals Cell Surface Structures: o Cell walls maintains cell shape, protects cell, prevents bursting in hypotonic environment o Eukaryote cell walls made of cellulose or chitin o Bacterial cell walls contain peptidoglycan: network of sugar polymers crosslinked by polypeptides o Scientists use gram stain to classify bacteria by cell wall composition Grampositive: bacteria w/ simpler walls and a large amount of peptidoglycan Gramnegative: bacteria w/ less peptidoglycan and an outer membrane that can be toxic to humans o Archaea contain polysaccharides and proteins BUT lack peptidoglycan; stain mostly Gramnegative (BUT staining doesn’t correlate w/ taxonomic subdivisions) Antibiotics target peptidoglycan and damage bacterial cell walls o Gramnegative bacteria more likely to be antibiotic resistant o Polysaccharide or protein layer called capsule covers many prokaryotes Many prokaryotes form metabolically inactive endospores, can remain viable in harsh conditions for centuries Some prokaryotes have fimbriae allow them to stick to their substrate or other individuals in a colony o Pili/pilus (sex pili) longer than fimbrae and allow prokaryotes to exchange DNA Many bacteria exhibit taxis ability to move toward or away from stimulus o Chemotaxis movement toward or away from chemical stimulus o Most propel themselves by flagella scattered about surface or concentrated at one or both ends Flagella of bacteria, archaea, and eukaryotes composed of different proteins and likely evolved independently Internal Organization and DNA in Prokaryotic cells: o usually lack complex compartmentalization o specialized membranes that perform metabolic functions usually infoldings in plasma membrane o less DNA than eukaryotic genome o mostly circular chromosomes not surrounded by membrane, located in nucleoid region o some species have smaller rings of DNA called plasmids Reproduction: o prokaryotes reproduce quickly binary fission (can divide every 13 hours) o Key features: small, binary fission, SHORT generation times o Considerable genetic variation: 3 factors: Rapid Reproduction and Mutation: Prokaryotes reproduce by binary fission, offspring cells are generally identical Mutation rates w/ binary fission are low, but because of rapid reproduction, mutations can accumulated rapidly in a population short generation time = evolve quickly NOT “primitive” prokaryotes are highly evolved Genetic Recombination: combining of DNA from 2 sources, contributes to diversity DNA from different individuals brought together by transformation, transduction, and conjugation movement of genes among individuals from different species horizontal gene transfer Transformation: prokaryotic cell can take up an incorporate foreign DNA from surrounding environment Transduction: movement of genes between bacteria by bacteriophages (viruses that infect bacteria) Conjugation and Plasmids: process where genetic material is transferred between prokaryotic cells (equivalent to mating or sexual reproduction) in bacteria, DNA transfer is one way donor cell attached to recipient by pilus, pulls it closer, and transfers DNA piece of DNA called F factor is required for the production of pili F Factor as a Plasmid: o Cells containing F plasmid function as DNA DONORS during conjugation o Cells w/out F factor function as DNA RECIPIENTS during conjugation o F factor transferable during conjugation. F Factor in the Chromosome: o cell w/ F factor BUILT INTO chromosomes function as donor during conjugation o recipient becomes RECOMBINANT bacterium w/ DNA from 2 different cells o R Plasmids and Antibiotic Resistance: R plasmids: carry genes for antibiotic resistance antibiotics kill sensitive bacteria, but NOT bacteria w/ specific R plasmids Thru natural selection, fraction of bacteria w/ genes for resistance increases in population exposed to antibiotics antibiotic resistant strains are becoming more common Metabolic diversity of prokaryotes: o photoautotrophs energy from light o chemoautotrophs energy from inorganic chemicals o photoheterotroph energy from light but needs organic compounds to live o chemoheterotroph energy from organic compounds Oxygen in Metabolism: o Obligate aerobes require Oxygen for cellular respiration o Obligate anaerobes poisoned by O2 and use fermentation or anaerobic respiration o Facultative anaerobes can survive W/OUT Oxygen Nitrogen fixation: convert atmospheric nitrogen (N2) to ammonia (NH3) o nitrogen essential for production of amino acids and nucleic acids Bacteria o (subgroup Alpha Proteobacteria) Rhizobium forms root nodules in legumes and fixes atmospheric N2 Agrobacterium produces tumors in plants and is used in genetic engineering o (subgroup Gamma Proteobacteria) Escherichia coli resides in the intestines of mammals and isn’t normally pathogenic Extremophiles: archaea that live in extreme environments o Extreme halophiles: live in highly saline environments o Extreme thermophiles: thrive in very hot environments Methanogens: live in swamps and marshes & produce methane as waste product o strict anaerobes & are poisoned by Oxygen gas Symbiosis: two species live close together (larger host and smaller symbiont) Mutualism: both symbiotic organisms benefit Commensalism: one organism benefits while neither harming nor helping the other in any major way Parasitism: organism called parasite harms BUT doesn’t kill host o Parasites that cause disease are called pathogens Exotoxins: secreted by pathogenic prokaryotes and causes disease even if prokaryotes that produce them are not present Endotoxins: released only when bacteria die and their cell walls break down (outer membrane of Gramnegative bacteria) Bioremediation: use of organisms to remove pollutants from environment o bacteria can be engineered to produce vitamins, antibiotics, and hormones Protists = informal name of group of mostly unicellular eukaryotes o constitute a polyphyletic group (no longer a valid kingdom) o structural and functional diversity most unicellular but some are colonial and multicellular singlecelled can be very complex o Mixotrophs combine photosynthesis and heterotrophic nutrition o Heterotrophs absorb organic molecules or ingest larger food particles o Photoautotrophs contain chloroplasts o Some reproduce asexually or sexually by sexual process of meiosis and fertilization Endosymbiosis: relationship b/w two species in which one organism lives inside the cell or cells of other organism (host) Secondary endosymbiosis: ingested by heterotrophic eukaryote Excavata: protists w/ modified mitochondria and protists w/ unique flagella o characterized by cytoskeleton o “excavated” feeding groove o includes Trichomonas, Giardia “SAR” clade: diverse monophyletic supergroup o controversial o includes brown algae (kelp), diatoms, Plasmodium (malaria) o Diatoms: unicellular algae w/ unique 2part, glasslike wall of silicon dioxide major component of phytoplankton and are highly diverse o Brown algae: largest and most complex algae multicellular, includes “seaweeds” Parts: Holdfast: anchors the alga Stipe: stem like structure that supports the blades Blades: leaflike structure supported by stipe Apicomplexans: parasites of animals and some cause serious human disease o most have sexual & asexual stages that require 2 or more different host species for completion Red algae and green algae are closest relatives of land plants Archaeplastida: supergroup that includes red algae, green algae, and land plants o Red algae: reddish in color due to pigment called phycoerythrin usually multicellular most abundant large algae in coastal waters of tropics o Green algae: named for grassgreen chloroplasts in paraphyletic group, plants descended from green algae 2 main groups: Charophytes: most closely related to land plants Chlorophytes Unikonta: supergroup that includes animals, fungi, and some protists o 2 clades: amoebozoans, and opisthokonts Entamoebas: parasites of vertebrates and some invertebrates Opisthokonts: includes animals, fungi, and several groups of protists Protists = (MAJOR) KEY roles in ecological communities: o found in diverse aquatic and moist terrestrial environments Rol : Symbiont Symbiotic protists: o some benefit their hosts ex) dinoflagellates nourish coral polyps that build reefs wooddigesting protists inhabit the gut of termites Producer: obtain energy from the sun Aquatic environments: photosynthetic protists and prokaryotes are main producers photosynthetic protists limited by nutrients o w/ rising sea temperatures biomass of photosynthetic protists have declined Greening of Earth: o Cyanobacteria & protists likely existed on land 1.2 billion yrs ago o 500 million yrs ago small plants, fungi, animals on land o 290,000 living species of plants o Land plants: having terrestrial ancestors, even though some are aquatic DON’T include photosynthetic protists (certain algae) Green algae (charophytes) closest relatives of land plants: o Comparisons of nuclear and chloroplast genes are evidence LAND PLANTS DID NOT DESCEND FROM MORDERN CHAROPHYTES Share the following traits: Rings of cellulosesynthesizing proteins (enzyme rosette)(nonmorphological character) Structure of flagellated sperm Formation of phragmoplast (in telophase of cytokinesis) Charophytes have layer of durable polymer sporopollenin prevents exposed zygotes from drying out: o also found in plant spore walls o movement on land by charophyte ancestors provided unfiltered sun, more plentiful CO2 and nutrientrich soil o land represented challenges: a scarcity of water and lack of structural support Desired Traits of Plants: o 5 key traits appear in nearly all land plants BUT are absent in charophytes (derived character = NOT shared ancestral character) 1 . Alternations of generations: a. Plants alternate b/w 2 multicellular stages, reproductive cycle called alternation of generations b. gametophyte: haploid and produces haploid gametes by mitosis c. Fusion of gametes gives rise to diploid sporophyte, which produces haploid spores by meiosis 2 . Multicellular, dependent embryos: a. Diploid embryo is retained w/ in tissue of female gametophyte b. Nutrients transferred from parent embryo thru placental transfer cells c. Land plants called embryophytes because of dependency of embryo on parent. 3 . Walled spores produced in sporangia: a. Sporophyte produces spores in organs called sporangia b. Diploid cells called sporocytes undero meiosis to generate haploid spores c. Spore walls contain sporopollenin, makes them resistant to harsh environments 4 . Multicellular Gametangia: a. Gametes produces w/in organs called gametangia b. Female gametangia, called archegonia, produce eggs and are site of fertilization c. Male gametangia, called antheridia, produce and release sperm 5 . Apical Meristems: a. Plants sustain continual growth in apical meristems b. Cells from apical meristems differentiate into various tissues o Additional derived traits: o Cuticle: waxy covering of epidermis o Stomata: openings b/w cells that allow for gas exchange b/w outside air and plant o Mycorrhizae: symbiotic association b/w fungi and land plants that may have helped plants w/out true roots to obtain nutrients Land plants can be informally grouped based off presence or absence of vascular tissue Most plants have vascular tissue; these constitute the vascular plants (vascular tissue = vascular plant) Ferns and other seedless vascular plants 1 to grow tall: o Vascular tissues allowed plants to grow tall o Seedless vascular plants have flagellated sperm and are usually restricted to moist environments ALL seed plants are heterosporous Heterosporous species produce megaspores, which give rise to female gametophytes, and microspores, give rise to male gametophytes
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'