BIOD 171 MODULE 4 ACTUAL EXAM WITH VERIFIED CORRECT DETAILED ANSWERS WITH RATIONALES (VERIFIED ANSWERS)|GRADED A+ BRAND NEW!!!!!!!!!

BIOD 171 MODULE 4 ACTUAL EXAM WITH VERIFIED CORRECT DETAILED ANSWERS WITH RATIONALES (VERIFIED ANSWERS)|GRADED A+ BRAND NEW!!!!!!!!! What is another name for a liquid growth media, and what are the basic components? - correct answer-Growth media in a liquid form is often referred to as nutrient broth. As the name implies its composition consists primarily of essential 'ingredients' such as a rich source of sugars, amino acids, and vitamins. Together, a nutrient broth provides the microbe with a source of carbon/energy, which, in turn, encourages its expansion. What is selective media? - correct answer-Selective media allows for only the growth of certain microbes while restricting the growth of all others. What is differential media? - correct answer-Differential media is used to distinguish between two (or more) related microbes. What are the requirements of a fastidious microbe? - correct answer-A fastidious microbe is an organism with complex growth requirements such that if absent it will not grow. Enriched medias thus contain these specific and essential nutrients required for the growth of a particular subset of microorganisms. What is agar? - correct answer-In its simplest form agar is liquid growth media that has had a hardening agent added to it. Agar is created when a polysaccharide derived from seaweed (algae) extract is added to growth media. Agar is used to create a solid, smooth surface on which microbes can grow. LB agar is classified as a non-selective, differential media True False - correct answer-False LB agar is non-selective and non-differential What are the three forms of hemolysis found on blood agar plates? - correct answer-Alpha hemolysis, beta hemolysis, and gamma hemolysis Alpha hemolysis - correct answer-Presents with greenish-brown color on blood agar due to the partial lysis of red blood cells Beta hemolysis - correct answer-Clear zones on blood agar indicate beta hemolysis, which is the complete lysis of red blood cells Gamma hemolysis - correct answer-Presents a white/tan on blood agar due to the lack of hemolytic activity. What is the primary purpose of Columbia CNA agar? - correct answer-As it suppresses the growth of Gram-negative bacteria CNA agar is, therefore, used for isolation of Gram-positive microbes. Name the type of plate derived from BAP that contains lysed red blood cells - correct answer-Lysed red blood cells (RBCs) are a primary component in the formulation of Chocolate agar. Define the selective and differential abilities of a MacConkey agar plate - correct answer-MacConkey agar is selective in that only Gram-negative microbes will grow on the agar -Gram-positive microbes simply do not grow. MacConkey agar is also considered a differential media as it distinguishes between microbes capable of fermenting lactose (red colonies) and those that are non-fermenters (white/tan colonies). What colors would you expect to see on an EMB plate containing E. coli? - correct answer-The EMB plate itself is red in color while in the presence of E. coli, the growing colonies will take on a distinctive metallic green sheen. What is the name of the process of spreading a bacterial culture onto a petri dish? - correct answer-Plating. Plating microbes can be done using a sterile loop, a sterile swab, or a sterilized wire loop. Each device is simply a means of spreading the bacteria, most commonly in a simple back-and-forth motion, across the plate. What is the primary advantage of plating a bacterial culture as opposed to having it grow in solution? - correct answer-The primary advantage of plating a bacterial sample onto agar is that cells are held in place. Unlike in a nutrient broth where bacterial cells can multiply but are free to move around in solution, bacteria plated onto agar are fixed in such a way as to support the formation and visualization of colonies. What is the purpose of the quadrant streak approach? - correct answer-The purpose of this method is to generate an individual colony so that a single (pure) bacterial sample can be picked from the plate. In a three-phase dilution gradient, which phase most likely contains individual colonies: phase 1 (P1) or phase 3 (P3)? - correct answer-Individual colonies are most likely going to appear within the phase 3 streaks. You being with P1 (highest concentration), dilute during P2 and then further dilute the sample in P3. However, it is possible to see individual colonies in P2 if only a small portion of P1 was carried over into P2. What growth requirements are necessary for growth and survival? - correct answer-Nutrients, temperature, and pH Photoautotrophs - correct answer--Organisms that use light as a source of energy and carbon dioxide as a source of carbon -Plants, algae, cyanobacteria Chemoautotrophs - correct answer--Organisms that use chemicals as a source of energy and carbon dioxide as a source of carbon -Hydrogen, sulfur, and nitrifying bacteria, some archaea Photoheterotrophs - correct answer--Organisms that use light as a source of energy and organic compounds as a source of carbon -Green nonsulfur bacteria and purple nonsulfur bacteria, archaea Chemoheterotrophs - correct answer--Organisms that use chemical compounds as a source of energy and organic compounds as a source of carbon -Most animals, fungi, and protozoa and many bacteria Toxic reactive oxygen species (ROS) - correct answer--1O2, O2-, O2 2-, OH- Obligate anaerobes - correct answer-Organisms that cannot live where molecular oxygen is present (so ROS is toxic) Obligate aerobes - correct answer-Organisms that contain enzymes and antioxidants that protect from ROS Facultative anaerobes - correct answer--Organisms that live in environments w/ or w/o oxygen -An example is E. coli What makes up 14% of the dry weight of bacterial cells? - correct answer-Nitrogen What is the growth-limiting nutrient? - correct answer-Nitrogen Trace elements - correct answer-Required by an organism in only minute quantities Growth factors - correct answer-Organic chemicals needed in small quantities to support metabolism Extreme thermophiles - correct answer--Archaebacteria that live in extremely hot environments, such as hydrothermal vents under the ocean -65-120C