Biol152 1st EditionExam # 2 Study Guide Lectures: 9 - 12Lecture 9 (February 12)What information do fossils provide scientists with? - Fossils provide time dimensions and record life’s history; it helps document the evolution of new taxa and helps to trace a character of evolutionHow does cell size relate to diffusion?- The smaller the diameter of the cell allows for fast diffusion, for example bacteria are small and have successful diffusion of nutrients and waste through the entire organismWhat types of organisms are identified as prokaryotes?- Archaea and bacteria are prokaryotes.What are some common characteristics of Archaea and bacteria?- Both lack and nuclear membrane, lack membrane-bound organelles, contain circular chromosomes and are extremely small in size.How do Archaea and bacteria reproduce?- Asexually, through binary fission where the cell divides in half producing two new cells- Genetic variation, by horizontal gene transfer1. Conjugation, a plius forms between two cells acting as a bridge for the DNA to transfer from one cell to the other2. Bacterial transformation, a donor cell dies and the remaining DNA is taken by a recipient cell3. Bacterial transduction, a virus latches on to a cell and forces the cell to penetrate other cells and obtains their DNAsWhat is the difference between anaerobic and aerobic respiration?- Anaerobic respiration does not use oxygen for respiration, and uses carbon dioxide instead, usually in areas with low oxygen- Aerobic respiration uses oxygen for respiration Lecture 10 (February 19) What are the categories of metabolic diversity?- Photoautotrophs, gain energy from sun and carbon from carbon dioxide- Photoheterotrophs, gain energy from the sun and carbon from consuming other organisms- Chemoautotrophs, gain energy from chemical compounds and carbon from carbon dioxide- Chemoheterotrophs, gain energy from chemical compounds and carbon from consuming other organismsWhat is Symbiosis?- Symbiosis is an intimate physical relationship between two organisms1. Commensalism one organism benefits and other is not effected2. Parasitism one organism is harmed while the other benefits3. Mutualism both organisms benefitWhat are some characteristics of eukaryotes?- Contain a “true nucleus”, nuclear membrane, membrane-bound organelles and mitochondriaReproduction in EukaryotesSexual and asexual reproductions are the two types of reproduction that are identified in eukaryotic organisms. The advantages of asexual reproduction are that it occurs at a fast pace, energy is not wasted looking for and attracting a mate. The advantage of sexual reproduction is an increased genetic variation.Sexual Life cycleThere are four different sexual life cycles in eukaryotic organisms. In a unicellular eukaryotic organism, its sexual life cycle could be prominently in the haploid phase, or prominently diploid phase. In animals, which are multicellular organisms, they go through meiosis to reproduce. In vascular plants the cycle starts out in haploid multicellular body then gametic cells, which fuse together to create a zygoteLecture 11 (February 24)Important Eukaryotic cladesThere are several important clades in the eukaryotic phylogenetic tree. The Opisthokonts, is the most diverse clade and contains organisms with complex multi-cellularity, among these are animals. The Amoebozoans include both free-living and parasitic forms of amoeba. The Archaeoplastids includes photosynthetic eukaryotes; among these are red algae (algae with red pigment), Green algae, land plants, and charophytes (thesister taxa to land plants). The Stramenopiles include algae, and protists containing hairy flagellum, and brown algae (the largest and most complex algae and are multi-cellular). A sub-group of the Stramenopiles is the Diatoms, which include phytoplankton, are photoautotrophs; contain cell walls and yellow-brown color. Another important eukaryotic clade is the Alveolates and is composed of several sub-groups, the dinoflagellates, the ciliates and the apicomplexans. The dinoflagellates contain two flagella, a cellulose-composed cell wall, planktonic auto-, hetero- or mixotrophs, are important for symbiosis and cause harmful algal blooms (leading to fish death). The Ciliates contain multiple cilia, are marine heterotrophs, include a micro and macronucleus. The Apicomplexans includes parasites and an apex with penetrating organelles (the plasmodium,causing malaria).Multi-cellularitySimple multi-cellularity includes organisms with cell adhesion; little cell-to-cell communication, little differentiation, and typically all functions are performed by all the cells. However overtime, there has been an evolution of multi-cellularity for enhanced feeding, anti-predatory adaptation and maintenance of position. The evolution is from simple multi-cellularity to complex multi-cellularity. In complex multi-cellularity organisms contain cell adhesion, lots of cell-to-cell communication, and there is lots of cell differentiation where cells are specialized to form different functions.Cell communication and differentiationCells communicate through different means; these are gap junctions, ion channels, intercellular junctions and plasma desmoda (in plants). Cell differentiation occurs through gene regulation, regulatory genes and a network of interactions requiring intercellular communication, such as the nervous system in humansLecture 12 (March 3)What are the plant tissues?- Dermal, ground and vascularWhat is the main function of a leaf?- PhotosynthesisWhat causes stomata to open?- Uptake of solutes by guard cells that cause water to be drawn inWhat causes stomata to close?- Release of solutes out of the guard cells and water to flow outHow is water and sugar transported?- By bulk flow through the phloem(sugar) and xylem