Microbiology Introduction
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Questions and Answers

What is the definition of microbiology?

  • The science that deals with the study of microorganisms of nucleus
  • The science that deals with the study of microorganisms that cannot be seen by naked eye. (correct)
  • The science that deals with the study of microorganisms of cellular membrane.
  • The science that deals with the study of microorganisms that can be seen by naked eye.

How are microorganisms divided according to their structure?

  • According to their nucleus membrane and type of nucleus (correct)
  • According to their nucleus and cellular wall
  • According to their cellular membrane and shape
  • According to their nucleus and mitochondria

What are Eukaryotes?

  • They are microorganisms that have a nucleus without a membrane.
  • They are microorganisms that have a nucleus with a membrane. (correct)
  • They are microorganisms that do not have a nucleus.
  • They are microorganisms that do not have a cellular membrane.

What are viruses?

<p>They are genetic material inside a cellular membrane. (A)</p> Signup and view all the answers

What are Prokaryotes?

<p>They are microorganisms that have a nucleus without a membrane. (B)</p> Signup and view all the answers

What is the main function of the bacterial cell wall?

<p>To provide shape to the cell (A)</p> Signup and view all the answers

What is the function of the plasmid in a bacterial cell?

<p>To carry extra genetic information (B)</p> Signup and view all the answers

What is the role of the cytoplasmic membrane in a bacterial cell?

<p>To regulate the movement of substances in and out of the cell (A)</p> Signup and view all the answers

What is the function of the cell structure mentioned?

<p>To rescue the cell from antibodies and harmful chemicals (A)</p> Signup and view all the answers

What is the function of the ribosome in a bacterial cell?

<p>To synthesize proteins (D)</p> Signup and view all the answers

What type of substances does the cell structure protect against?

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

What is the outcome if the cell structure fails to function?

<p>The cell is damaged by harmful chemicals (A)</p> Signup and view all the answers

What is the function of the flagella in a bacterial cell?

<p>To provide movement to the cell (D)</p> Signup and view all the answers

What is the function of the pili in a bacterial cell?

<p>To provide attachment to surfaces (A)</p> Signup and view all the answers

What is NOT a function of the cell structure?

<p>Producing harmful chemicals (A)</p> Signup and view all the answers

What is the function of the chromosome in a bacterial cell?

<p>To carry genetic information (D)</p> Signup and view all the answers

What is the relationship between the cell structure and antibodies?

<p>The cell structure rescues the cell from antibodies (A)</p> Signup and view all the answers

Why is the bacterial cell wall important?

<p>It protects the cell from the environment (C)</p> Signup and view all the answers

What is the classification of bacteria based on?

<p>Outer structure (cell wall) (B)</p> Signup and view all the answers

What is characteristic of Gram positive bacteria?

<p>Thick peptidoglycan layer (D)</p> Signup and view all the answers

What is the function of Teichoic acids?

<p>Act as major surface antigen determinants (A)</p> Signup and view all the answers

What is the main component of the cell wall in Gram positive bacteria?

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

What is the main difference between Gram positive and Gram negative bacteria?

<p>Outer structure (cell wall) (C)</p> Signup and view all the answers

What is the characteristic of the cell wall in Gram positive bacteria?

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

What is the relationship between Teichoic acids and peptidoglycan?

<p>Teichoic acids are intertwined with peptidoglycan (D)</p> Signup and view all the answers

What is the term for the thick layer in Gram positive bacteria?

<p>Peptidoglycan layer (D)</p> Signup and view all the answers

What is the characteristic of the peptidoglycan layer in Gram-positive bacteria?

<p>Several layers thick (B)</p> Signup and view all the answers

What is the difference in the outer membrane between Gram-positive and Gram-negative bacteria?

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

Which type of toxin is produced by Gram-positive bacteria?

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

What is the characteristic of the cell wall of Gram-negative bacteria?

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

Why are Gram-negative bacteria more virulent?

<p>Due to the presence of an outer membrane (A)</p> Signup and view all the answers

What is the characteristic of lipopolysaccharides?

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

Which type of antibiotics are Gram-positive bacteria susceptible to?

<p>Cell wall targeting antibiotics (B)</p> Signup and view all the answers

What is the characteristic of teichoic acids?

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

Flashcards

What is Microbiology?

The study of microorganisms that are too small to be seen with the naked eye.

What are Eukaryotes?

Organisms with a nucleus enclosed within a membrane.

What are Prokaryotes?

Organisms without a nuclear membrane, their genetic material is free-floating.

What are Viruses?

A non-cellular entity containing genetic material enclosed in a protein coat.

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What is a Bacterial Cell Wall?

The rigid outermost layer of a bacterial cell, providing shape and protection.

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What is a Cytoplasmic Membrane?

The selectively permeable membrane surrounding the bacterial cytoplasm.

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What is a Chromosome in a Bacterial Cell?

The main DNA molecule in a bacterium, containing most of its genetic information.

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What are Plasmids?

Small circular DNA molecules found in bacteria, carrying extra genes.

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What are Ribosomes?

Organelles responsible for protein synthesis in bacteria.

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What are Flagella?

Whip-like structures used by some bacteria for movement.

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What are Pili?

Hair-like appendages found on some bacteria, used for attachment.

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What is one function of the Bacterial Cell Wall?

It protects the plasma membrane and internal components from environmental stress.

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What is another function of the Bacterial Cell Wall?

It allows the cell to attach to surfaces and other bacteria.

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What are Gram Positive Bacteria?

Bacteria with a thick peptidoglycan layer in their cell wall.

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What are Gram Negative Bacteria?

Bacteria with a thin peptidoglycan layer in their cell wall.

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What is the Gram Stain?

A staining technique used to differentiate bacteria based on their cell wall structure.

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What is Peptidoglycan?

A complex polymer found in bacterial cell walls, giving them structural integrity.

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What are Teichoic Acids?

Polymers present in the cell walls of Gram-positive bacteria.

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What is the Outer Membrane?

The outer layer of the cell wall in Gram-negative bacteria, composed of lipids and proteins.

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What are Lipopolysaccharides?

A complex molecule present in the outer membrane of Gram-negative bacteria.

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What are Exotoxins?

A toxic substance released by bacteria that can cause damage to the host.

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What are Endotoxins?

A toxic component of the outer membrane of Gram-negative bacteria, released upon cell lysis.

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What is Virulence?

The ability of a microorganism to cause disease.

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What is the main difference between Gram-positive and Gram-negative bacteria?

The main difference between Gram-positive and Gram-negative bacteria is the thickness of their cell wall.

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How does the cell wall structure affect the resistance of bacteria?

Gram-positive bacteria have a thicker layer of peptidoglycan in their cell wall, making them more resistant to certain environmental conditions.

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How does cell wall thickness affect bacterial virulence?

Gram-positive bacteria are generally considered less virulent because their thick cell wall makes it harder for them to invade host cells.

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Why are Gram-negative bacteria more resistant to certain antibiotics?

Gram-negative bacteria tend to be more resistant to cell wall-targeting antibiotics because their outer membrane provides an extra layer of protection.

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How do Gram-positive and Gram-negative bacteria differ in terms of teichoic acids?

Gram-positive bacteria have teichoic acids present in their cell wall, while Gram-negative bacteria do not.

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How do Gram-positive and Gram-negative bacteria differ in terms of toxins?

Gram-positive bacteria produce exotoxins, while Gram-negative bacteria produce endotoxins.

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How does the number of layers in the cell wall differ between the two types of bacteria?

Gram-positive bacteria have only one layer in their cell wall, whereas Gram-negative bacteria have two layers.

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Study Notes

Microbiology

  • Microbiology is the science that deals with the study of microorganisms that cannot be seen by the naked eye.

Classification of Microorganisms

  • Microorganisms can be classified into three categories based on their structure:
    • Eukaryotes (have a nuclear membrane)
    • Prokaryotes (do not have a nuclear membrane)
    • Viruses (not a cell, just a genetic material inside a membrane)

Bacterial Cell Structure

  • Components of a bacterial cell:
    • Cell wall
    • Cytoplasmic membrane
    • Chromosome
    • Plasmid
    • Ribosome
    • Flagella
    • Pili

Function of Bacterial Cell Wall

  • Provides support for the cell's characteristic shape
  • Protects the plasma membrane and other cytoplasmic inclusions from adverse environments
  • Provides support for attachment to the flagella
  • Rescues the cell from antibodies and harmful chemicals

Classification of Bacteria

  • Bacteria can be classified into two large groups based on their cell wall structure:
    • Gram positive bacteria
    • Gram negative bacteria

Characteristics of Gram Positive Bacteria

  • Thick peptidoglycan layer in their cell wall
  • Simpler chemical structure with a thick peptidoglycan layer
  • Teichoic acids are intertwined among the peptidoglycan and are the major surface antigen determinants

Characteristics of Gram Negative Bacteria

  • Thin peptidoglycan layer in their cell wall
  • More complex chemical structure with a thin peptidoglycan layer
  • Rich in lipids and have an outer membrane consisting of a lipid bilayer with phosphate and proteins
  • No teichoic acids in their cell wall

Difference between Gram Positive and Gram Negative Bacteria

  • Gram positive bacteria:
    • No outer membrane
    • Thick peptidoglycan layer
    • Teichoic acids present
    • Less virulent
    • Susceptible to cell wall targeting antibiotics
    • One layer in the cell wall
    • No lipopolysaccharides
    • Produce exotoxins
  • Gram negative bacteria:
    • Outer membrane present
    • Thin peptidoglycan layer
    • Teichoic acids absent
    • More virulent
    • Resistant to cell wall targeting antibiotics
    • Two layers in the cell wall
    • Lipopolysaccharides present
    • Produce endotoxins

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Explore the science of microbiology, studying microorganisms that cannot be seen with the naked eye, including their classification into prokaryotes and eukaryotes.

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