Cell Catalase Oxidase Gram(+) Bacteria Cell Catalase Oxidase Gram(-) Bacteria Shape Shape (+) (-) Bacillus subtilis (+) (-) Escherichia coli rod rod (+) (+) Staphylococcus (+) (-) Haemophilus rod aureus cocci baemolticus (+) Bacillus megaterium (+) +)or() Proteus vulgaris rod rod (+) (-) Staphylococcus (+) (-) Shigella flexneri rod sanropbyticus (+) (+) Streptococcus grglis (-) (-) Pseudomonas rod cocci aeruginosa (-) Streptococcus (-) Sitrobecter.treundel (+) pneumoniae cocci pod Streptococcus (-) (-) Klebsiella (+) (-) pneumoniae cocci pneumonige rod Enterococcus (-) (-) Serratia marcescens (+) (-) faecalis cocci rod The Content File has the information. The Study Guide just asks for the answers. Feel free to make notes about the tests. YOU CAN ABBREVIATE THE NAMES FOR THE FOLLOWING EXERCISE BUT DO NOT LEAVE ANY OUT ON ANY STEP Below is George's first question about his unknown: Dichotomous Key Question 1: Is the organism Catalase positive? No (Those that would not bubble Cat-) Yes (List species that would bubble Cat+) 1. Using the Table above find and list on the left side all the organisms that are catalase + and on the right side list all that are catalase -. You may abbreviate the organism names. 2. Circle the list above that contains George's unknown bacteria 3. Go to the table and CROSS OUT every species in the un-circled list. We never want to consider them again during our pursuit of George's unknown! Cross. Them. Out.
Added by Whitney C.
Close
Step 1
Using the table above, we can identify the organisms that are catalase positive (+) and catalase negative (-): Catalase positive (+): Bacillus subtilis, Staphylococcus, Bacillus megaterium, Proteus vulgaris, Streptococcus grglis, Streptococcus pneumoniae, Show more…
Show all steps
Your feedback will help us improve your experience
Dominador Tan and 63 other Biology educators are ready to help you.
Ask a new question
Labs
Want to see this concept in action?
Explore this concept interactively to see how it behaves as you change inputs.
Key Concepts
Recommended Videos
1) Based on the virtual lab "catalase test", which bacteria was positive (+) or negative (-)? bacteria | catalase (+/-) Staphylococcus aureus | positive Streptococcus pyogens | negative 2) Try the virtual "oxidase test" multiple times to check all following bacteria. Majority of bacteria listed below are human pathogens (We can do easily in the virtual lab.). You probably need to re-start several times to see all bacteria on this list. bacteria | oxidase (+/-) Pseudomonas aeruginosa | positive Neisseria gonorrhoeae | positive Yersinia pestis | negative Salmonella typhi | negative Serratia marcescens | negative Neisseria megingitidis | positive Klebsiella pneumoniae | negative Enterobacter aerogenes | negative Escherichia coli | negative 3) In addition to the production of hydrogen peroxide, what other harmful species of oxygen can be produced by alternative pathways of the electron transport chain, and how are they neutralized? 4) The oxidase test must be read within 20 seconds of starting the experiment. How would you interpret an oxidase test that developed a coloar change at 40 seconds? Explain your answer.
Sri K.
1. Compare the growth on both plates to your predicted results from the Experiment Setup worksheet table. Do you see any discrepancies? Comment in 1-2 sentences. 2. Observed catalase reaction for E. coli growing on both plates were very different. Perform online research and try to explain why this is the case. Suppose that these catalase results were expected and trustable. 3. Pseudomonas aeruginosa is a Gram-negative, catalase-positive opportunistic pathogen, often incorrectly classified as an obligate aerobe. It can cause life-threatening infections in immunocompromised people, such as patients with cystic fibrosis. In their lungs, it forms robust biofilms. Deep biofilm layers contain no oxygen, and P. aeruginosa cannot ferment. How does it obtain ATP energy for growth? Do your online research and explain in a few sentences.
Suman K.
Catalase test The catalase test is used to differentiate staphylococci (catalase-positive) from streptococci (catalase-negative). The enzyme catalase is produced by bacteria that respire using oxygen and protects them from the toxic by-products of oxygen metabolism. Catalase-positive bacteria include strict aerobes as well as facultative anaerobes, although they all have the ability to respire using oxygen as the terminal electron acceptor. Catalase-negative bacteria may be anaerobes or facultative anaerobes that only ferment and do not respire using oxygen as the terminal electron acceptor (i.e. Streptococci). Steps: 1. Smear specimen on the slide. 2. Apply hydrogen peroxide (2-3 drops). 3. Record the reaction. Coagulase Test Coagulase is an enzyme produced by Staphylococcus aureus that converts soluble fibrinogen plasma to insoluble fibrin. Other staphylococci do not produce coagulase, thus this test can distinguish aureus from other staphylococci. Steps: 1. Smear specimen on the slide. 2. Apply rabbit plasma (1 drop). 3. Swirl around a little. 4. Record the reaction.
Keemin L.
Recommended Textbooks
Biology for AP Courses
Objective Biology for NEET
Introduction to General, Organic and Biochemistry
18,000,000+
Students on Numerade
Trusted by students at 8,000+ universities
Watch the video solution with this free unlock.
EMAIL
PASSWORD