MBIO 3401 STUDY SET-QUESTIONS AND
ANSWERS | WITH COMPLETE SOLUTION
What are the 4 traits of a microbe?
-Too small to be seen by human eye
-Grow and reproduce in nature
-Active metabolism
-Respond to stimuli
Diameter of a typical microbe?
0.2 micrometers (μm) in diameter
Who was the first person to observe single-celled microbes?
Antonie van Leeuwenhoek
Where do microbes come from?
they have parents
who disproved theory of spontaneous generation?
Louis Pasteur
Louis Pasteur contribution to microbiology?
disproved spontaneous generation
Who proved the link between microbes and infectious disease?
Robert Koch
,Robert Koch's contribution to microbiology?
Link between microbes and infectious disease.
What are the two primary types of cells?
Prokaryotic and Eukaryotic
Is bacteria prokaryotic or eukaryotic?
Prokaryotic
Is archaea prokaryotic or eukaryotic?
Prokaryotic
Primary purpose of light microscope?
Improve contrast and resolution
What is contrast?
the difference in brightness between the light and dark areas of an image
What is resolution of an image?
Ability to distinguish between two objects.
5 types of light microscopy?
-Bright Field
-Phase contrast
-Differential Interference Contrast
,-Dark-field
-Fluorescence
Color of Gram + cells after gram stain?
Purple
Color of gram - cells after gram stain
Red/pink
What is confocal scanning laser microscopy?
A computerized fluorescent microscope that uses a laser source to create a 3D image
Pros and Cons of Bright-field microscopy:
Pros: Simple and affordable
Cons: need staining and difficult to see small/colorless cells
Pros and Cons of dark field microscopy:
Pros: Highly sensitive for small cells/structures
Cons: poor resolution and prone to artifacts
Pros and Cons of Phase contrast microscopy and differential interference microscopy:
Pros: See live cells w/out stain, see some internal structures
Cons: Hard for small cells
Pros and Cons of Fluorescence and Confocal Microscopes:
, Pros: High resolution, 3D, vibrant colors, live cells
Cons: expensive
What is electron microscopy?
Uses electrons rather than visual light
Advantage of electron microscopy?
Greater resolution than light microscope
Role of transmission electron microscopy (TEM):
-See internal structures
-Obtain 3D images
Role of Scanning Electron Microscopes (SEM):
see surface and external structures
What is passive transport?
The movement of materials across the cell membrane without using cellular energy and with
concentration gradient
What is active transport?
the movement of ions or molecules across a cell membrane into a region of higher concentration,
assisted by enzymes and requiring energy.
Role of the cell wall?
Maintain shape and rigidity
ANSWERS | WITH COMPLETE SOLUTION
What are the 4 traits of a microbe?
-Too small to be seen by human eye
-Grow and reproduce in nature
-Active metabolism
-Respond to stimuli
Diameter of a typical microbe?
0.2 micrometers (μm) in diameter
Who was the first person to observe single-celled microbes?
Antonie van Leeuwenhoek
Where do microbes come from?
they have parents
who disproved theory of spontaneous generation?
Louis Pasteur
Louis Pasteur contribution to microbiology?
disproved spontaneous generation
Who proved the link between microbes and infectious disease?
Robert Koch
,Robert Koch's contribution to microbiology?
Link between microbes and infectious disease.
What are the two primary types of cells?
Prokaryotic and Eukaryotic
Is bacteria prokaryotic or eukaryotic?
Prokaryotic
Is archaea prokaryotic or eukaryotic?
Prokaryotic
Primary purpose of light microscope?
Improve contrast and resolution
What is contrast?
the difference in brightness between the light and dark areas of an image
What is resolution of an image?
Ability to distinguish between two objects.
5 types of light microscopy?
-Bright Field
-Phase contrast
-Differential Interference Contrast
,-Dark-field
-Fluorescence
Color of Gram + cells after gram stain?
Purple
Color of gram - cells after gram stain
Red/pink
What is confocal scanning laser microscopy?
A computerized fluorescent microscope that uses a laser source to create a 3D image
Pros and Cons of Bright-field microscopy:
Pros: Simple and affordable
Cons: need staining and difficult to see small/colorless cells
Pros and Cons of dark field microscopy:
Pros: Highly sensitive for small cells/structures
Cons: poor resolution and prone to artifacts
Pros and Cons of Phase contrast microscopy and differential interference microscopy:
Pros: See live cells w/out stain, see some internal structures
Cons: Hard for small cells
Pros and Cons of Fluorescence and Confocal Microscopes:
, Pros: High resolution, 3D, vibrant colors, live cells
Cons: expensive
What is electron microscopy?
Uses electrons rather than visual light
Advantage of electron microscopy?
Greater resolution than light microscope
Role of transmission electron microscopy (TEM):
-See internal structures
-Obtain 3D images
Role of Scanning Electron Microscopes (SEM):
see surface and external structures
What is passive transport?
The movement of materials across the cell membrane without using cellular energy and with
concentration gradient
What is active transport?
the movement of ions or molecules across a cell membrane into a region of higher concentration,
assisted by enzymes and requiring energy.
Role of the cell wall?
Maintain shape and rigidity
