MBIO 3401 Exam 1 Questions with Complete
Solutions
List Koch's Postulates in order for defining the causative agent of a disease. 1. The
microbe is found in call cases of the disease, but is absent from health individuals.
2. The microbe is isolated from the diseased host and grown in pure culture.
3. When the microbe is introduced into a healthy host, the same disease occurs.
4. The same strain of microbe is obtained from the newly diseased host.
Who was the first scientist to develop the first vaccine based on attenuated strains? What two
vaccinations did he develop? Louis Pasteur. He developed Fowl Cholera vaccination and
Rabies vaccination.
Define immunization The stimulation of an immune response by deliberate inoculation
with an attenuated pathogen.
,Who discovered that Penicillium mold generated a substance that kills bacteria?
Alexander Fleming.
Who purified penicillin and made it the first commercial antibiotic to save human lives?
Howard Florey and Ernst Chain.
Who first used solid medium using agar to grow pure cultures of microbes? Angelina and
Walther Hesse.
How does the human eye observe images? Light focuses onto retina where photoreceptor
cells fire signals that are transmitted to optic nerve to the brain to generate images.
Define Resolution. The smallest distance by which two opbjects can be separated and
distinguished.
What is the resolution of the human retina? What does this mean? 150 micrometers, or,
0.15 mm.
,This means that if two objects are closer than 150 micrometers together, the human eye cannot
distinguish between the two objects.
Who was Ignaz Semmelweis? Semmelweis ordered doctors to wash their hands with
chlorine. He was the first to introduce aseptic techniques in the hospitals.
Who was Joseph Lister? He developed carbolic acid to treat wounds and clean surgical
instruments in 1865.
What type of microscopy generates a dark image over a light background? Bright-field
microscopy.
How do you find total magnification? magnification of ocular multiplied by that of the
objective.
Example: ocular = 10x and objective = 20x. Total magnification = 200x.
, How do resolution and magnification work together to produce a clear image under microscope?
Increase of magnification results in larger image and increase in resolution produces a
clearer image.
True or false: less than 0.1% of all microbial species can be cultured in the laboratory.
True.
What is the wavelength of visible light? 400-750 nm.
Absorption. Means that the photon's energy is acquired by the absorbing object.
Reflection. Means that the wavefront bounces off the surface of an object.
Refraction. The bending of light as it enters a substance that slows its speed.
Scattering. Occurs when the wavefront interacts with an object smaller than the
wavelength of light.
Solutions
List Koch's Postulates in order for defining the causative agent of a disease. 1. The
microbe is found in call cases of the disease, but is absent from health individuals.
2. The microbe is isolated from the diseased host and grown in pure culture.
3. When the microbe is introduced into a healthy host, the same disease occurs.
4. The same strain of microbe is obtained from the newly diseased host.
Who was the first scientist to develop the first vaccine based on attenuated strains? What two
vaccinations did he develop? Louis Pasteur. He developed Fowl Cholera vaccination and
Rabies vaccination.
Define immunization The stimulation of an immune response by deliberate inoculation
with an attenuated pathogen.
,Who discovered that Penicillium mold generated a substance that kills bacteria?
Alexander Fleming.
Who purified penicillin and made it the first commercial antibiotic to save human lives?
Howard Florey and Ernst Chain.
Who first used solid medium using agar to grow pure cultures of microbes? Angelina and
Walther Hesse.
How does the human eye observe images? Light focuses onto retina where photoreceptor
cells fire signals that are transmitted to optic nerve to the brain to generate images.
Define Resolution. The smallest distance by which two opbjects can be separated and
distinguished.
What is the resolution of the human retina? What does this mean? 150 micrometers, or,
0.15 mm.
,This means that if two objects are closer than 150 micrometers together, the human eye cannot
distinguish between the two objects.
Who was Ignaz Semmelweis? Semmelweis ordered doctors to wash their hands with
chlorine. He was the first to introduce aseptic techniques in the hospitals.
Who was Joseph Lister? He developed carbolic acid to treat wounds and clean surgical
instruments in 1865.
What type of microscopy generates a dark image over a light background? Bright-field
microscopy.
How do you find total magnification? magnification of ocular multiplied by that of the
objective.
Example: ocular = 10x and objective = 20x. Total magnification = 200x.
, How do resolution and magnification work together to produce a clear image under microscope?
Increase of magnification results in larger image and increase in resolution produces a
clearer image.
True or false: less than 0.1% of all microbial species can be cultured in the laboratory.
True.
What is the wavelength of visible light? 400-750 nm.
Absorption. Means that the photon's energy is acquired by the absorbing object.
Reflection. Means that the wavefront bounces off the surface of an object.
Refraction. The bending of light as it enters a substance that slows its speed.
Scattering. Occurs when the wavefront interacts with an object smaller than the
wavelength of light.
