Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Microbiology Final
FINAL LAB
| Question | Answer |
|---|---|
| What is the color of gram negative and gram positive? | Positive = Dark purple, Negative = Red/Pink |
| What shape is Vibrio bacteria? | Comma-shaped spiral |
| What shape are Streptococci, Streptobacilli bacteria? | Chains of cells |
| What shape are Tetrad bacteria? | Squares of 4 cells |
| What shape are Diplococci & Diplobacilli bacteria? | Pairs of cells |
| What shape are Spirillum bacteria? | Wavy-shaped spiral |
| What shape are Spirochete bacteria? | Corkscrew-Shaped Spiral |
| What shape are Coccus, Cocci bacteria? | Spheres |
| What shape are Staphylococci bacteria? | Clusters of cells |
| What shape are Sarcina, Sarcinae bacteria? | Cubes of 8 cells |
| What shape are Bacillus, Bacilli bacteria? | Rods |
| Describe the KOH test to differentiate Gram positive from Gram negative bacteria. | The cell wall of Gram Neg is easily disrupted by dilute base. When cell walls are disrupted, threads of DNA are released from the bacteria & are the thin string observed. Weak basic solution have no detectable effect on the cell wall of Gram Pos. |
| Define Ubiquity | Ubiquity means that something can be found everywhere. It is an actual physical presence unlike omnipresent. |
| What disease does Bacillus Anthracis cause? | Antrax |
| What disease does Clostridium Tetani casue? | Tetanus (Lockjaw) |
| What disease does Clostridium Botulinum casue? | Botulism |
| What is Selective Media? | Specific for the isolation or cultivation of a specific organism. |
| What is Differential Media? | Incorporates ingredients designed to show results of chemical reactions that vary between different organisms grow on the same medium. |
| Is MacConkeys agar selective or differential (both or neither)? | BOTH |
| Is a blood agar plate selective or differential (both or neither)? | Differential |
| What is the catalase test for and what reagent does it use? | The purpose of the catalase test is to differentiate staphylococci from streptococci. This is possible because streptococci does not produce catalase and all staphylococci produce catalase. Hydrogen Peroxide (H202) is used. |
| What is the Coagulase test for? | It is used to differentiate Staphylococcus Aureus from other forms of Staphylococci. Staphylococcus produces Coagulase and other forms of staphylococci do not. |
| How is carbohydrate fermentation determined? | When sugars are fermented by bacteria, energy is released and small molecules of acids are produced. Some bacteria produce acid and gas during fermentation. Color can remain red if pH is near neutral. Color turns yellow when acidic. |
| How does a positive hydrogen sulfide test appear? | Dark precipitate |
| How does a positive urease test appear? | Bright pink |
| How does a positive citrate test appear? | Blue color |
| A bacterial plate count form a urine culture of 1000 – 10000 bacteria/mL = ? | Probably contamination of sample |
| A bacterial plate count form a urine culture of 10000 – 100000 bacteria/mL = ? | Possibility of UTI |
| A bacterial plate count from a urine culture of >100000 bacteria/mL = ? | Establishes the presence of a UTI |
| Why are sometimes molecular techniques used to identify pathogens instead of traditional methods? | B/C many pathogens grow poorly on solid medium while others grow only in liquid culture, making identification through traditional techniques difficult or impossible. With the aid of molecular methods, however, these limitation can be overcome. |
| What are the 4 basic steps involved in the bacterial identification lab? | 1. Prepare a sample from a patient and isolate whole bacterial DNA. 2. Make many copies of the desired piece of DNA. 3. Sequence DNA. 4. Analyze the sequence and ID the bacteria |
| What is 16S rDNA? | 16S rDNA is one of the 3 RNA molecules associated with the ribosomes of prokaryotes. It can be used as a gene to be copied |
| How can 16S rDNA be used to identify bacteria? | 16S rDNA can be used to identify bacteria because some parts of the gene are similar among different species and some are variable. The primer binds to the similar parts so that the DNA can be copied. The variable parts are then used for identification. |
| Describe the sample preparation that will yield the whole bacterial DNA. | 1st you dissolve the cell with a digestive buffer. Then you denature the enzyme using heat (A H2O Bath @ 100 degrees C) Then you centrifuge. Cellular debris = SOLID, DNA = LIQUID |
| Briefly, what is PCR? | Polymerase Chain Reaction. It is a technique that allows many copies of DNA to be made. |
| What are the 3 steps in PCR? | 1. Separation of the strands, 2. Annealing the primer to the template, 3. Synthesis of the new strand. |
| What are primers? | Small pieces of DNA that bind to specific sequences of known DNA. The process allows replication of the specific known segment of DNA. |
| What is meant by conserved and variable regions of DNA? | CONSERVED = The parts of the genes that are extremely similar among different species. VARIABLE = Regions that differ between species. |
| What methods of purifying PCR products did you use? | Using a microconcentrator column. |
| How does Cycle Sequencing differ from PCR? | You use a thermocycler just like PCR, BUT, you terminate the replication process at random places so the copies are all partial sequences w/ different lengths. |
| How did BLAST give you an identification of your unknown bacteria? | It took the gene sequence and found what bacteria it was from a database. |
| What is a “similarity score”? | A score given to the degree of similarity between 2 DNA sequences. 1 point = each base pair match. 0 points = base pairs that don’t match. The more nucleotides that match, the higher the score. |
| Describe Alpha Hemolysis. | Ex. Streptococci able to lyse erythrocytes but only partially break down the heme pigment develop a green halo around each colony. |
| Describe Beta Hemolysis. | Ex. Streptococci, which produce hemolytic enzymes, which totally degrade the heme pigment, leaving a clear zone around each colony. |
| Describe Gamma Hemolysis. | Ex. Colonies, which do not cause any visible change in pigmentation of the BAP. |
| Which hemolysis is a lab looking for in diagnosing a strep throat? | Beta Hemolytic (Streptococcus Pyrogens/Group A beta Hemolytic) |
| What is the importance of a capsule? | Capsules can have an anti-phagocytic effect. Capsules allow the organism to resist destruction by alveolar macrophages & establish infection in the respiratory tract. It can be important to determine if the stain present in a disease is capsulated or not. |
| What stain shows a capsule? | A counterstain such as Gin Stain. Methylene blue is also often used as the counterstain. When observed under the microscope such a preparation shows halos or clear rings around pale blue bacterial cells against a dark background. |
| What is the name of the acid-fast stain and what is it used for? | Ziehl-Neelsen procedure. Acid fast organisms possess a cell wall rich in lipids, complex lipids and waxes. Primary stain is driven into the cell using heat, by steaming. Acid fast cells appear red. Non-acid-fast cells are counterstained and appear blue. |
| What 3 bacteria does the FDA recommend for disinfectant testing? | Staphylococcus aureus, Pseudomonas aeruginosa, Salmonela typhi. |
| What is Staphylococcus aureus representative of? | Gram positive. Major cause of wound infections. |
| What is Pseudomonas aeruginosa representative of? | Gram negative aerobes. Pseudomonas infections are uncommon, but when they do occur they are serious. |
| What is Salmonela typhi representative of? | Gram-negative facultative anaerobes. Present in fecal material, which is one of the most difficult materials to successfully disinfect. |
| Define what a titer is. | A serial dilution of serum is made & mixed with a fixed amount of antigen and agglutination or precipitation of the test tube is looked for. The highest dilution showing a positive reaction is the titer. |
| Which immunoglobulin appears first when someone has an infection? | IgM |
| Define Prozone. | At 1st no precipitate will be fourmed in dilution of antibodies w/ antigen. As [antibody] decreases w/ dilution small amounts of precipitate will be formed. Continued dilution will result in decrease. This is the Prozone Phenomenon. |
| How is a positive Western Blot for HIV determined? | HIV is lysed to release its proteins and the HIV proteins are then separated by size and molecular charge using gel electrophoresis. If antibodies are present, they will show a dark band on the strip. |
| Are Bacteria or Yeast smaller? | Bacteria are smaller |
| Where does yeast Cryptococcus cause serious infection? | It can cause serious infections in the lungs. It is also thought to cause meningitis. |
| Define dimorphic fungi. | A fungi that is able to exist as yeasts or molds |
| Define budding in yeast. | It is a way in which yeast divides by producing smaller copies of themselves called a bud which grows into a new yeast cell |
| How would a Gram Stain be used with fungi? | Yeast stain gram positive and can be distinguished from bacteria, which are smaller then yeast. |
| How would an India Ink Preparation be used with fungi? | Preparation of spinal fluid is made when Cryptococcus is suspected to be causing meningitis. Cryptococcus can have a large capsule which in an India Ink Preparation will show as a clear area surrounding the yeast cell. |
| What is the scotch tape test? | When pinworm infection diagnosis is found using scotch tape. It is put against the perianal folds and the pinworm eggs stick to tape. |
| What is the disease or condition called CYSTICERCOSIS and what parasite causes it? | Taenia soium casued by cestode (Pork Tapeworm) |
| What is the infective stage of Giardia and how is it diagnosed? | Ingestion of Cyst. Stool Sample to look for cysts or trophozoites. |
| What is the infective stage of Necator Americanus (Hookworm) and how is it diagnosed? | Direct skin penetration of filariform larvae. Stool sample to look for ova. |
| What is the infective stage of Ascaris and how is it diagnosed? | Ingestion of Ova (eggs). Stool sample to look for ova. |
| What is the infective stage of Taenia saginata & T. solium (Beef or Pork tapeworm) and how is it diagnosed? | Ingestion of larval stage (cysticercus) in beef or pork tissue. Stool sample to look for ova or proglottids. |
| What is the infective stage of Trichomonas and how is it diagnosed? | Sexual transmission of trophozoite (NO CYST STAGE). Genital secretions for a wet mount to look for moving trophozoite. |
| Give the insect vector for Trypanosoma brucei. | Tsetse Fly (Glossina) |
| Give the insect vector for Trypanosoma cruzi. | Reduviid bug |
| Give the insect vector for Leismania. | Sand Fly (Phlebotomus) |
| Give the insect vector for Plasmodia. | Female Mosquito (Anopheles) |
| What 2 roundworms or nematodes have a larval stage migrating though the host lungs? | Ascaris Lumbricoides, Necator Americanus |
| What 2 parasites use direct skin penetration as the way to enter a new host? | Schistosoma (Blood Fluke), Necator Americanus (Hookworm) |
| What stage of plasmodia in the mosquito is the infective stage for humans? | Sporozoite |
| What stage of plasmodia in the human host is the infective stage for mosquitoes? | Gametocyte |
| What stage in the plasmodia life cycle is occurring when the human host experiences fever and chills? | Merozoite. |
| In which host does the asexual reproductive cycle of plasmodia take place? | In humans. |
| In which host does the sexual reproductive cycle of plasmodia take place? | In mosquitoes. |
| Where in the human host does Toxoplasma gondii infect? | CNS, Heart or skeletal muscle |
| In what host does the sexual reproductive cycle of Toxoplasma gondii occur? | CATS |
| What Parasite causes African Sleeping Sickness? | Trypansoma BRUCEI (Tsetse fly [Glossina]). |
| What parasite causes Chagas Disease? | Trypanosoma CRUZI (Reduviid bug) |
| How would an individual get a Trichinella infection? | By eating raw or undercooked pork and wild game infected with the larvae of a parasitic worm. |
Created by:
Tanman1216