BIOL 110 Basic Concepts and Biodiversity Learning Guide Tutorial The Biology of Prokaryotes II In this tutorial we will continue our exploration of prokaryotes by looking at their diverse metabolic modes as well as the symbiotic relationships that bacteria participate in We will also learn about the role of bacteria in global nitrogen and oxygen cycles Read through the questions below before you begin reading the prokaryotes II tutorial Then as you read the tutorial fill in your answers to help you prepare for our class session In addition to the questions below as you read through the tutorial ask yourself what did I learn on this page Before our class session answer the following questions from the online tutorial 1 Distinguish between the four major modes of nutrition noting which are unique to prokaryotes 2 An organism was recently discovered in a salty environment that can obtain its energy from sunlight and can obtain its carbon from organic compounds This organism is an example of a A photoautotroph B photoheterotroph C chemoautotroph D chemoheterotroph Defend your answer in two sentences or less 3 Describe the three types of symbiotic relationships covered in your tutorial and give an example of each You will have to know how to apply and recognize these relationships 4 After reading A Real Life Example Growing plants in disease suppressive soil answer the following questions A What hypothesis were the researchers testing in this study B What is the independent variable in this study C What is the dependent variable in this study 5 After reading A Real Life Example Bacteroides thetaiotaomicron and the human gut answer the following questions A Briefly explain why commensalism is not an adequate description of our relationship with Bacteroides thetaiotaomicron B What is our symbiotic relationship with Bacteroides thetaiotaomicron C Is Bacteroides thetaiotaomicron a gram negative or gram positive bacterium 6 What types of oxygen tolerance exist among organisms Use the chart below to compare these different modes Obligate aerobe Obligate anaerobe Facultative anaerobe Require oxygen Require an anaerobic environment Can use oxygen but doesn t require it 7 List what concepts or ideas from this tutorial are new to you During our class session work with your peers LAs and instructor to answer the following questions 1 All organisms need a source of carbon as well as a source of energy Carbon can come from either CO2 or organic molecules and energy can come from either sunlight or energy rich inorganic molecules Using this information fill in the table below by naming the four different modes of metabolism Then answer these questions A Which mode s do humans use B Which mode s do other eukaryotes use C Which mode s do prokaryotes use 2 A researcher discovers a new species of bacteria that obtains its energy from hydrogen sulfide and its carbon from the atmosphere This species can be categorized based upon its mode of nutrition as a A chemoheterotroph B photoautotroph C photoheterotroph D chemoautotroph 3 Staphylococcus epidermidis bacteria commonly live on human skin of healthy individuals When the bacteria can invade deeper into the human body for example into the bloodstream or heart staph infections can become deadly even for otherwise healthy individuals Based on this information when the skin is intact and the bacteria cannot invade the relationship is a When the bacteria invade into the bloodstream or heart the relationship is a A commensalism mutualism B mutualism parasitism C commensalism parasitism D parasitism mutualism 4 A real life example Growing plants in disease suppressive soil Sugar beet seeds were planted in separate pots with 32 seeds in each of five soil treatments The pots were inoculated with Rhizoctonia solani and placed in greenhouses kept at 20 C with a 16 hour light 8 hour dark cycle After 20 days the percentage of infected sugar beet seedlings was determined for each soil treatment The results of the experiment are shown in this table A What hypothesis were the researchers testing in this study B What is the independent variable in this experiment C What is the dependent variable in this experiment D Which of the following graphs accurately represents the data from this experiment a b c E Which of the following results would refute not support the hypothesis that microorganisms are responsible for the disease suppressive properties of soils A if seedlings had similar fungal infection rates when grown in heated and unheated disease suppressive soil B if seedlings had similar fungal infection rates when grown in disease suppressive soil and soil from the margin of the field C if seedlings had similar fungal infection rates when grown in 100 and 10 disease suppressive soil D no results could have rejected the hypothesis that microorganisms are responsible for the disease suppressive properties of soil 5 The first appearance of oxygen in the atmosphere likely triggered a massive wave of extinctions among the prokaryotes of the time This is because A most organisms at that time were facultative anaerobes B most organisms at that time were obligate anaerobes C most organisms at that time were obligate aerobes D oxygen readily combines with carbon to create toxic CO2 At the end of our class session reflect on your learning by answering the following questions 1 What concepts were not clear 2 List questions you can bring to LA or instructor student office hours this week