Gram Staining Quiz

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

Gram staining is a method used in microbiology and bacteriology to classify bacterial species into two large groups. What are these two groups?

  • Gram-positive and Gram-variable
  • Gram-positive and Gram-negative (correct)
  • Gram-negative and Gram-indeterminate
  • Gram-variable and Gram-indeterminate

Who developed the Gram staining technique?

  • Hans Christian Gram (correct)
  • Hans Christian Gram and Carl Friedländer
  • Carl Friedländer
  • Lugol

What is the purpose of adding Lugol's iodine solution in the Gram staining technique?

  • To differentiate gram-positive and gram-negative bacteria
  • To diagnose a fungal infection
  • To strengthen the bonds of the stain with the cell membrane (correct)
  • To make bacteria more visible in stained sections of lung tissue

Which phylum includes well-known genera such as Lactobacillus, Bacillus, and Staphylococcus?

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

What type of bacteria possess a thin layer of peptidoglycan between two membranes?

<p>Gram-negative bacteria (A)</p> Signup and view all the answers

Which type of bacteria cannot be determined as either gram-positive or gram-negative?

<p>Gram-indeterminate bacteria (A)</p> Signup and view all the answers

Which bacteria lack a cell wall around their cell membranes and do not stain by Gram's method?

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

Which staining technique is used to differentiate bacterial species into gram-positive and gram-negative groups?

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

What is the purpose of the decolorization step in the Gram staining technique?

<p>To remove the crystal violet stain from gram-negative cells (C)</p> Signup and view all the answers

Which type of bacteria has a thick mesh-like cell wall made of peptidoglycan and stains purple in the Gram staining technique?

<p>Gram-positive bacteria (C)</p> Signup and view all the answers

In a modern microbiology lab, what is the preferred method for bacterial identification?

<p>Genetic sequences and molecular techniques (A)</p> Signup and view all the answers

Flashcards

Gram staining

A technique used in microbiology to classify bacteria into two large groups based on their cell wall structure.

Gram-positive bacteria

A group of bacteria that possess a thick layer of peptidoglycan in their cell wall and stain purple in the Gram staining technique.

Gram-negative bacteria

A group of bacteria that have a thin layer of peptidoglycan between two membranes and stain pink in the Gram staining technique.

Lugol's iodine solution

A solution used in Gram staining to strengthen the bonds of the stain with the cell membrane.

Signup and view all the flashcards

Decolorization

A step in Gram staining used to remove the crystal violet stain from gram-negative cells, leaving them colorless.

Signup and view all the flashcards

Hans Christian Gram

A scientist who developed the Gram staining technique.

Signup and view all the flashcards

Firmicutes

A phylum of bacteria that includes well-known genera like Lactobacillus, Bacillus, and Staphylococcus. They are typically gram-positive.

Signup and view all the flashcards

Mycoplasma

Bacteria that lack a cell wall around their cell membranes and do not stain by Gram's method.

Signup and view all the flashcards

Gram-indeterminate bacteria

Bacteria that cannot be reliably classified as either gram-positive or gram-negative.

Signup and view all the flashcards

Genetic sequencing and molecular techniques

The preferred method in modern labs for identifying bacterial species, relying on genetic sequences and molecular techniques.

Signup and view all the flashcards

Gram staining

A technique used to differentiate bacterial species into gram-positive and gram-negative groups based on their cell wall structure.

Signup and view all the flashcards

Study Notes

Gram Staining Technique

  • Classifies bacterial species into two large groups: Gram-positive and Gram-negative
  • Developed by Hans Christian Gram

Gram-positive Bacteria

  • Have a thick mesh-like cell wall made of peptidoglycan
  • Stain purple in the Gram staining technique
  • Examples: Lactobacillus, Bacillus, Staphylococcus (belong to the phylum Firmicutes)

Gram-negative Bacteria

  • Possess a thin layer of peptidoglycan between two membranes
  • Stain pink in the Gram staining technique

Gram Staining Process

  • Lugol's iodine solution is added to help the dye bind to the peptidoglycan layer
  • Decolorization step is used to remove excess dye from the Gram-negative bacteria

Exceptions

  • Some bacteria lack a cell wall and do not stain by Gram's method (e.g. Mycoplasma)
  • Some bacteria cannot be determined as either gram-positive or gram-negative (e.g. Mycobacterium)

Modern Microbiology Lab

  • Preferred method for bacterial identification is not Gram staining, but rather other methods such as molecular diagnostics and biochemical testing.

Studying That Suits You

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

Quiz Team

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser