Microbiology Chapter 1: Origin & History

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Questions and Answers

Which characteristic is unique to archaea when compared to other prokaryotes?

  • They are found in extreme environmental conditions. (correct)
  • They can be motile via flagella or cilia.
  • They reproduce through binary fission.
  • They possess a cell wall made of peptidoglycan.

What is a primary difference between fungi and protozoa in terms of their cellular structure?

  • Fungi can perform photosynthesis.
  • Fungi have cell walls made of chitin, while protozoa lack cell walls. (correct)
  • Fungi utilize pseudopods for movement, while protozoa use cilia.
  • Fungi are prokaryotic, while protozoa are eukaryotic.

Which of the following describes the role of viruses in biological systems?

  • They break down waste materials in the environment.
  • They reproduce within a host cell using the host's machinery. (correct)
  • They are composed of cells containing organelles and a nucleus.
  • They are free-living organisms that can perform photosynthesis.

Which scientist is credited with discovering the existence of cells through direct observation using a microscope?

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

Which factor is considered the primary limitation on the size of a cell?

<p>The surface area to volume ratio of the cell. (D)</p> Signup and view all the answers

What concept did Lazzaro Spallanzani's experiments directly help refute?

<p>The idea of spontaneous generation. (B)</p> Signup and view all the answers

What is the primary characteristic of antibiotics in the treatment of disease?

<p>They are produced naturally by bacteria and fungi to inhibit other microbes. (A)</p> Signup and view all the answers

What purpose do vaccines serve in protecting against infectious diseases?

<p>They induce immunity by exposing the body to harmless forms of the pathogen. (D)</p> Signup and view all the answers

According to Louis Pasteur's experiments, what is the correct origin of cells?

<p>Cells arise from other preexisting cells. (D)</p> Signup and view all the answers

Which type of microorganism is characterized by a cell wall made of cellulose?

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

Flashcards

What are Microbes?

Microscopic organisms that can only be seen with a microscope.

Are Microbes Good or Bad?

Microbes are important for various functions like breaking down waste, providing nutrients, and being part of the food chain, but some can cause disease.

Bacteria

Single-celled organisms with a cell wall made of peptidoglycan that reproduce asexually through binary fission.

Archaea

Prokaryotes similar to bacteria but lacking peptidoglycan in their cell walls. They often thrive in extreme environments.

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Protozoa

Unicellular eukaryotic microbes that move using pseudopods, cilia, or flagella. Some are parasites.

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Algae

Photosynthetic eukaryotes with diverse shapes and sizes that reproduce sexually or asexually.

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Fungi

Unicellular or multicellular eukaryotes with a cell wall made of chitin. They absorb nutrients from their environment.

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Viruses

Acellular microbes that require a host to reproduce. They contain DNA or RNA as their genetic material.

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What is Immunity?

The process of protecting against disease by introducing weakened or deactivated microbes into the body.

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Chemotherapy/Synthetic Drugs/Antibiotics

Chemicals used to treat diseases. Synthetic drugs are made in labs, while antibiotics are naturally produced by bacteria or fungi.

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Study Notes

Ch.l Origin & History

  • What are microbes?

    • Microscopic organisms only visible with a microscope
    • Examples include bacteria, fungi, protozoa, viruses, and archaea
  • Are microbes good or bad?

    • Both
    • Some break down waste and provide chemical elements, aid in photosynthesis, and aid in digestion
    • Others cause disease, like HIV and infections
  • Types of microorganisms

    • Bacteria:
      • Single-celled organisms
      • Cell walls made of peptidoglycan
      • Reproduce by binary fission
      • Can use organic chemicals, photosynthesis or inorganic substances
      • Some use flagella for movement
    • Archaea:
      • Prokaryotes
      • Similar to bacteria, but lack peptidoglycan
      • Often live in extreme environments (e.g., methanogens, halophiles, thermophiles)
    • Protozoa:
      • Unicellular eukaryotes
      • Move using pseudopods, cilia, or flagella
      • Exist as free-living organisms or parasites
    • Algae:
      • Photosynthetic eukaryotes
      • Various shapes and sizes
      • Reproduce sexually and asexually
      • Often made of cellulose
    • Fungi:
      • Unicellular or multicellular eukaryotes
      • Cell walls made of chitin
      • Reproduce sexually or asexually
      • Obtain food by absorbing organic material
    • Viruses:
      • Acellular (non-cellular) particles
      • Contain DNA or RNA as genetic material
      • Reproduce only within a host cell
  • Fred Sanger: Developed a method for rapidly sequencing DNA.
  • Florence Nightingale: Linked medical statistics to the impact of disease on soldiers.
  • Robert Hooke: Observed the smallest structures (cells) in cork using a microscope.
  • Antonie van Leeuwenhoek: Invented magnifying lenses, observed bacteria
  • Louis Pasteur: Conducted experiments on spontaneous generation of microorganisms and discovered vaccines
  • Rudolph Virchow: Proposed that all cells come from pre-existing cells.

Important experiments

  • Francesco Redi's experiment: Disproved spontaneous generation of maggots.

  • John Needham's experiment: Early experiment about spontaneous generation; however, flawed in design.

  • Lazzaro Spallanzani's experiment: Built upon Needham's work with improved design, disproving spontaneous generation in his experiments.

  • How microbes are utilized

    • Autoclaving: High-temperature method used to kill bacteria and other microbes

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