Biol152 1st Edition Exam 2 Study Guide Lectures 9 12 Lecture 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 evolution How 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 organism What 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 transfer 1 Conjugation a plius forms between two cells acting as a bridge for the DNA to transfer from one cell to the other 2 Bacterial transformation a donor cell dies and the remaining DNA is taken by a recipient cell 3 Bacterial transduction a virus latches on to a cell and forces the cell to penetrate other cells and obtains their DNAs What 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 organisms What is Symbiosis Symbiosis is an intimate physical relationship between two organisms 1 Commensalism one organism benefits and other is not effected 2 Parasitism one organism is harmed while the other benefits 3 Mutualism both organisms benefit What are some characteristics of eukaryotes Contain a true nucleus nuclear membrane membrane bound organelles and mitochondria Reproduction in Eukaryotes Sexual 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 cycle There 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 zygote Lecture 11 February 24 Important Eukaryotic clades There are several important clades in the eukaryotic phylogenetic tree The Opisthokonts is the most diverse clade and contains organisms with complex multicellularity 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 the sister 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 subgroups 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 cellularity Simple 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 differentiation Cells 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 humans Lecture 12 March 3 What are the plant tissues Dermal ground and vascular What is the main function of a leaf Photosynthesis What causes stomata to open Uptake of solutes by guard cells that cause water to be drawn in What causes stomata to close Release of solutes out of the guard cells and water to flow out How is water and sugar transported By bulk flow through the phloem sugar and xylem water