Fungi: Molds & Yeasts Overview
40 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which statement accurately describes the structure of non-septate hyphae?

  • It allows streaming of cytoplasm through septa.
  • It has cross-walls that separate individual cells.
  • It forms a dense mat of mycelium only.
  • It is characterized by continuous filaments without cross-walls. (correct)

What is the primary means by which yeasts reproduce?

  • Fragmentation
  • Hyphal extension
  • Binary fission
  • Budding (correct)

How do septate hyphae facilitate the growth of mold colonies?

  • By allowing individual cells to maintain separation.
  • By allowing for cytoplasm streaming through pores. (correct)
  • By blocking nutrient absorption.
  • By directly forming the mycelium structure.

What infection is primarily associated with Candida albicans?

<p>Thrush in newborns (B)</p> Signup and view all the answers

What is a distinguishing feature of yeast compared to molds?

<p>Yeasts reproduce primarily through budding. (C)</p> Signup and view all the answers

Which substance is used to disinfect work surfaces in the lab?

<p>Bleach (B)</p> Signup and view all the answers

What process describes the introduction of microorganisms into a culture medium?

<p>Inoculation (B)</p> Signup and view all the answers

Which of the following best describes media used for microbial growth?

<p>Nutrient-rich substances that can be liquid, solid, or semi-solid. (A)</p> Signup and view all the answers

What color indicates a positive result in a citrate test?

<p>Royal blue (B)</p> Signup and view all the answers

What is the expected color change in a urease test for a positive reaction?

<p>Hot pink/fuchsia (A)</p> Signup and view all the answers

How can you identify the presence of catalase in a culture?

<p>By detecting bubble formation after adding Hâ‚‚Oâ‚‚ (C)</p> Signup and view all the answers

Which type of bacteria produces green metallic colonies on EMB agar?

<p>Gram-negative bacteria that rapidly ferment lactose (B)</p> Signup and view all the answers

What type of hemolysis is characterized by the smallest ring around a colony on a blood agar plate?

<p>Alpha hemolysis (C)</p> Signup and view all the answers

What bacteria is specifically identified using the coagulase test?

<p>Staphylococcus aureus (D)</p> Signup and view all the answers

What does Mannitol-Salt Agar selectively isolate?

<p>Staphylococcus species (B)</p> Signup and view all the answers

What is the purpose of performing an oxidase test before using the Enteropluri test system?

<p>To assess if bacteria are oxidase-positive or negative (A)</p> Signup and view all the answers

What is the primary purpose of culturing microorganisms?

<p>To intentionally grow microorganisms for study or production (A)</p> Signup and view all the answers

Which type of culture media is NOT considered solid?

<p>Nutrient-rich broth (A)</p> Signup and view all the answers

What is the primary function of iodine in the Gram stain process?

<p>To enhance binding of the primary stain to gram+ cells (B)</p> Signup and view all the answers

Which characteristic indicates a pure culture when observing colonies?

<p>Consistent shape, size, and color across colonies (B)</p> Signup and view all the answers

How can the number of cells on a countable plate be calculated?

<p>(Number of colonies / 100) * 10^Dilution factor (D)</p> Signup and view all the answers

What is the purpose of using a higher-power objective lens in microscopy?

<p>To enhance magnification and detail of fine structures (B)</p> Signup and view all the answers

What technique is used to observe the motility of microorganisms?

<p>Hanging drop technique (A)</p> Signup and view all the answers

What does the term 'ubiquitous' refer to in the context of microorganisms?

<p>Microorganisms found in nearly every environment (A)</p> Signup and view all the answers

What should you avoid doing when handling the needle end of the tube?

<p>Touching the needle end with your hands (D)</p> Signup and view all the answers

What action should you take to ensure anaerobic conditions in the Enteropluri tube?

<p>Break the wire at the designated notch (A)</p> Signup and view all the answers

What result indicates a positive glucose reaction in the Enteropluri test?

<p>Complete separation of wax overlay from medium (C)</p> Signup and view all the answers

How should you analyze the biochemical reactions after incubation?

<p>All chambers should be examined for color changes (A)</p> Signup and view all the answers

What does a purple result in the lysine decarboxylase (LYS) chamber indicate?

<p>Decarboxylation of lysine has occurred (A)</p> Signup and view all the answers

What is the recommended incubation temperature and duration for the Enteropluri tube?

<p>37°C for 18 - 24 hours (B)</p> Signup and view all the answers

Why is it important to make holes in the plastic coverings of the depressions in the last eight compartments?

<p>To enable anaerobic growth (D)</p> Signup and view all the answers

What should be done with the wire after making holes in the chambers?

<p>Dispose of it in a biohazard bag (B)</p> Signup and view all the answers

What color indicates a positive result for the ornithine decarboxylation test?

<p>Purple (A)</p> Signup and view all the answers

What is the result of a successful indole formation test after adding Kovac's reagent?

<p>Pink/Red (B)</p> Signup and view all the answers

In the testing for H2S production, which color indicates a positive result?

<p>Black (B)</p> Signup and view all the answers

What is considered a potable level of coliform colonies in a water sample?

<p>1 coliform colony/100ml or less (A)</p> Signup and view all the answers

Which component of the laboratory procedures helps to inhibit gram-positive bacteria while allowing gram-negative bacteria to grow?

<p>EMB agar plate (A)</p> Signup and view all the answers

What color result indicates an alkaline condition for the urea test?

<p>Yellow (C)</p> Signup and view all the answers

During serological typing using the slide agglutination test, what is being identified?

<p>Microbial species using specific antibodies (A)</p> Signup and view all the answers

If both DUL and PA tests are positive, which of the following is true?

<p>It is impossible for both to be positive. (D)</p> Signup and view all the answers

Flashcards

Fungi hyphae

Microscopic, intertwining filaments that make up fungal colonies.

Septate hyphae

Fungal hyphae with cross-walls (septa) separating individual cells.

Non-septate hyphae

Fungal hyphae without cross-walls; a single, continuous cell.

Fungal mycelium

A branching, filamentous network formed by hyphae covering a substrate.

Signup and view all the flashcards

Yeast budding

Asexual reproduction in yeasts where a new cell forms and detaches.

Signup and view all the flashcards

Inoculation

Introducing microorganisms into a medium or host for growth or study.

Signup and view all the flashcards

Media (culture media)

Nutrient-rich substances supporting microbial or cellular growth.

Signup and view all the flashcards

Disinfection (workstation)

To clean and kill potential microbial contaminants, using a bleach solution.

Signup and view all the flashcards

Pure Culture Characteristics

A pure culture displays uniform colonies with consistent shape, size, color, and texture. No variations indicate a single microorganism type.

Signup and view all the flashcards

Bacterial Count Calculation

To get the total cell count, multiply the number of colonies on a countable plate by the dilution factor of the plate, then divide by 100.

Signup and view all the flashcards

Gram Stain Primary Stain

Crystal violet stains all cells purple by attaching to the cell wall.

Signup and view all the flashcards

Gram Stain Decolorizer

Ethanol removes the crystal violet-iodine complex from Gram-negative bacterial cells, leaving them colorless.

Signup and view all the flashcards

Hanging Drop Technique

A technique used to observe the motility (movement) of microorganisms.

Signup and view all the flashcards

Culture Media (Solid)

Solid growth media used for cultivating microorganisms, including nutrient agar, blood agar, MacConkey agar, and Mannitol Salt agar (MSA).

Signup and view all the flashcards

Higher Power Objective

Magnifies a specimen for better detail of cellular structures and microorganisms.

Signup and view all the flashcards

Inoculation of Agar Slant

Process of introducing a microorganism to a nutrient medium (like an agar slant) for growth and observation. Includes technique for preventing contamination.

Signup and view all the flashcards

Wet mount technique

A method to observe microbial motility. A drop of liquid culture is placed on a slide and covered with a coverslip.

Signup and view all the flashcards

Positive Citrate Test

A positive citrate test produces a royal blue color due to bromothymol blue indicator.

Signup and view all the flashcards

Negative Citrate Test

A negative citrate test results in a green color.

Signup and view all the flashcards

Positive Urease Test

A positive urease test turns hot pink/fuchsia, due to the indicator phenol red.

Signup and view all the flashcards

Catalase Test Positive

Formation of bubbles when hydrogen peroxide (Hâ‚‚Oâ‚‚) is added indicates a positive catalase test.

Signup and view all the flashcards

Mannitol-Salt Agar

A selective & differential medium to identify Staphylococcus bacteria, especially Staph. aureus (that appear yellow).

Signup and view all the flashcards

Agglutination

The clumping of bacterial cells caused by exposure to specific antibodies.

Signup and view all the flashcards

Enteropluri Test

A rapid method that combines various tests into one tube to identify Enterobacteriaceae bacteria.

Signup and view all the flashcards

Enteropluri Tube Inoculation

A method for inoculating a multi-compartment tube with bacteria to test for various biochemical reactions.

Signup and view all the flashcards

Wire Insertion Technique

The process of pushing a wire through all chambers of the Enteropluri tube, ensuring the tip reaches the last chamber, and then breaking the wire at a notch, leaving a portion in the tube.

Signup and view all the flashcards

Anaerobic Conditions

An environment lacking molecular oxygen, essential for certain reactions in the Enteropluri test, maintained by the wire fragment left inside the tube.

Signup and view all the flashcards

Glucose Fermentation

A chemical breakdown of glucose resulting in gas production, indicated by a separation of the wax overlay in the glucose chamber.

Signup and view all the flashcards

Lysine Decarboxylation

The breakdown of lysine, producing an acidic environment, indicated by a purple color in the Lysine chamber.

Signup and view all the flashcards

Kovac's Reagent

A reagent used to detect indole production, resulting in a red color on the surface of the medium in a positive test.

Signup and view all the flashcards

Positive Test Interpretation

A positive result in a particular chamber is marked by circling the corresponding number on the datasheet, indicating the presence of a specific biochemical reaction.

Signup and view all the flashcards

Toothpick Technique

Enlarging the hole in the H2S/indole chamber using a toothpick to allow for the addition of Kovac's reagent.

Signup and view all the flashcards

ORN

ORN stands for ornithine decarboxylase. A positive test is indicated by a purple color. If decarboxylation of ornithine does not occur, the result will be yellow.

Signup and view all the flashcards

H2S

H2S refers to hydrogen sulfide production. A black color indicates a positive result, while brown is considered negative.

Signup and view all the flashcards

IND

IND stands for indole formation. A pink/red color after applying Kovac's reagent indicates a positive result.

Signup and view all the flashcards

What is the color of a positive Citrate test?

A positive citrate test results in a blue color, indicating an alkaline pH change.

Signup and view all the flashcards

Water Potability

Water potability refers to the safety and suitability of water for drinking. Water is considered potable if it has less than 1 coliform colony/ml.

Signup and view all the flashcards

What is the purpose of the membrane filtration method in water testing?

The membrane filtration method helps detect microbes present in small concentrations by filtering a known volume of water through a membrane filter trapping bacteria. The filter is then grown on an EMB agar plate.

Signup and view all the flashcards

What is the purpose of the slide agglutination test?

The slide agglutination test helps identify microbial species by using antibodies that bind specifically to microbial antigens. The reaction creates cell clusters, or agglutination.

Signup and view all the flashcards

What is the difference between a positive and negative PA (phenylalanine deaminase) test?

A positive PA test results in a yellow color due to the acidic pH change, while a negative test shows a green color, indicating an alkaline pH change.

Signup and view all the flashcards

Study Notes

Fungi: Molds & Yeasts

  • Molds form colonies from microscopic, intertwined filaments called hyphae.
  • Hyphae are either septate (separated by cross-walls) or non-septate (no cross-walls).
  • Growth occurs at hyphae tips, forming a branching network called mycelium.
  • Mold colonies appear as a mat of hyphae on substrate.
  • Yeasts are fungi that do not typically form hyphae.
  • Yeasts reproduce by budding, where a new cell forms and separates from the parent.
  • Candida albicans is a yeast that can cause infections in humans, especially newborns.

Mold Identification

  • Inoculation is the introduction of microorganisms into a growth medium.
  • Various media include nutrient-rich agar, blood agar, MacConkey agar, mannitol salt agar, and eosin methylene blue agar (EMB).

Microbial Culture Techniques

  • Procedures for disinfection of work surfaces are essential.
  • Proper inoculation techniques (e.g., streaking on agar slants, swabbing) are crucial for isolating pure cultures.
  • Techniques for observing microbial motility (hanging drop method) and microscopic observation are used.

Gram Stain Process

  • Gram stain is used to differentiate bacteria by their cell walls.
  • Crystal violet stains all cells purple (primary stain).
  • Iodine forms a complex with crystal violet, enhancing binding (mordant).
  • Ethanol decolorizes gram-negative cells, leaving them colorless.
  • Safranin stains decolorized cells, making them pink/red (counterstain).

Bacterial Count Calculation

  • Bacterial counts are determined from dilution plates.
  • Count colonies on a plate with a countable number of colonies(30-300).
  • Use the formula: (number of colonies on plate) x (dilution factor of the plate) = number of cells per ml

Specific Tests

  1. Urease Test: Positive result appears as hot pink/fuchsia.
  2. Catalase Test: Presence of bubbles indicates positive result.
  3. Hemolysis Test on Blood Agar: Different types of hemolysis include alpha, beta, and gamma.
  4. Coagulase Test: Used to identify Staphylococcus aureus.
  5. Mannitol Salt Agar (MSA): Selective and differential medium for Gram-positive bacteria, especially Staphylococcus.

Membrane Filtration Method

  • Membrane filtration is a method for detecting coliforms to determine the potability of water.
  • Colonies are counted on EMB agar.
  • Less than 1 colony per 100 mL of water is generally considered potable.

Slide Agglutination Test

  • Slide agglutination tests use antibodies specific to microbial antigens to identify microbial species.
  • A positive result causes clumping (agglutination).

Enteropluri Test System

  • A single tube that incorporates 15 biochemical tests for identifying gram-negative bacteria.
  • Includes tests for carbohydrate fermentation, enzyme production, and gas production.

Biochemical Reactions of Enteropluri Tests

  • Various tests are used including those for lactose, urea, glucose, Hâ‚‚S production, indole, ornithine, and citrate.
  • Specific colors or production of gas in the wells/chambers indicate test results

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Cumulative Lab Final PDF

Description

Explore the fascinating world of fungi, focusing on molds and yeasts. Learn about the structure and growth of molds, including hyphae and mycelium, as well as the unique characteristics of yeasts like Candida albicans. This quiz covers key identification and culture techniques essential for studying these microorganisms.

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser