Microbiology - Lab Final Short Answer Questions
Why is it important to calculate the diameter of the field when first using the microscope?
It is important to calculate the diameter of the field of view when first using the microscope because it allows y
estimate how large the details seen on the slides are.
Using the field of view calculated in Exercise 1 for the high power lens, what is the approximate diame
of the cells in the Bacteria Coccus Form slide in Photo 10? Show your calculations.
The field of view calculated for the high power lens was 1000 µM, or 10mm. Since I counted that approximatel
across the diameter of the field of view at high power, 1000/60=16.7, so each cell is approximately 16.7 µM in
The optical microscope is regularly used to identify pathogenic microbes. In 1918 the Spanish Flu infe
one third of the world and was thought to be caused by bacteria. However, a virulent virus was the cau
Spanish Flu.From what we have learned throughout this lab on microscopy, why weren’t scientists ab
the Spanish Flu with an optical microscope?
,Virulent viruses, such as the one that caused the Spanish Flu, are much smaller than most bacteria. Although
microscopes are able to view most bacteria, scientist wouldn't have been able to identify the Spanish Flu as th
virus is too small to be seen using the optical microscope.
What is the purpose of wiping down your work area with bleach before and after an experiment?
It disinfects your work area, both to ensure your samples are not contaminated as well as to decontaminate th
surface to protect yourself and those around you from being exposed to the microbes used.
List five safety precautions you used to protect yourself while culturing microbes.
1. Disinfected my work area by wiping it down with bleach after the experiment.
2. Wore safety equipment (gloves, goggles, face mask, and apron).
3. Kept tubes tilted away from mouth and nose when opened.
4. Washed hands with soap and warm water immediately after finishing.
5. Placed all items that needed to be disposed of that came into contact with microbes in undiluted bleach for
minutesbefore disposal.
What is the purpose of a broth in a microbiology laboratory?
The broth serves as a liquid growth media for the microbes, it provides all the nutrients necessary for the micro
reproduce.
, Did each of your cultures develop at the same rate? Why might your incubation environment favor one
over another?
They did not develop at the same rate, specifically S. cerevisiae developed slower than the other two cultures.
many different factors that can influence rate of bacteria growth. Each bacteria has a different optimal environm
reproduction, with slightly different optimal temperatures or pH levels.
What is a colony and how does a colony relate to a bacterial cell? Why are colonies important in the st
microbiology?
A colony is a mass of cells that all are derived from the same original cell, one colony is made up of an entire g
bacterial cells. Colonies are important because they allow researchers to grow larger samples of a specific str
bacteria from a single cell, which allows them to more easily study one individual strain.
Are bacteria easier to observe on a plate or in a broth? How do the bacteria look on the plate as compa
broth?
Bacteria are easier to observe on a plate than in broth. On a plate you are able to identify individual colonies, a
see differences in the morphology of those colonies (such as shape, margin, elevation, and size). In broth how
only able to identify more basic evidence of bacterial growth, such as turbidity and flocculent growth.
How could you tell if one of the colonies on your pure plate was a contaminant from the environment a
come from your original culture?
Why is it important to calculate the diameter of the field when first using the microscope?
It is important to calculate the diameter of the field of view when first using the microscope because it allows y
estimate how large the details seen on the slides are.
Using the field of view calculated in Exercise 1 for the high power lens, what is the approximate diame
of the cells in the Bacteria Coccus Form slide in Photo 10? Show your calculations.
The field of view calculated for the high power lens was 1000 µM, or 10mm. Since I counted that approximatel
across the diameter of the field of view at high power, 1000/60=16.7, so each cell is approximately 16.7 µM in
The optical microscope is regularly used to identify pathogenic microbes. In 1918 the Spanish Flu infe
one third of the world and was thought to be caused by bacteria. However, a virulent virus was the cau
Spanish Flu.From what we have learned throughout this lab on microscopy, why weren’t scientists ab
the Spanish Flu with an optical microscope?
,Virulent viruses, such as the one that caused the Spanish Flu, are much smaller than most bacteria. Although
microscopes are able to view most bacteria, scientist wouldn't have been able to identify the Spanish Flu as th
virus is too small to be seen using the optical microscope.
What is the purpose of wiping down your work area with bleach before and after an experiment?
It disinfects your work area, both to ensure your samples are not contaminated as well as to decontaminate th
surface to protect yourself and those around you from being exposed to the microbes used.
List five safety precautions you used to protect yourself while culturing microbes.
1. Disinfected my work area by wiping it down with bleach after the experiment.
2. Wore safety equipment (gloves, goggles, face mask, and apron).
3. Kept tubes tilted away from mouth and nose when opened.
4. Washed hands with soap and warm water immediately after finishing.
5. Placed all items that needed to be disposed of that came into contact with microbes in undiluted bleach for
minutesbefore disposal.
What is the purpose of a broth in a microbiology laboratory?
The broth serves as a liquid growth media for the microbes, it provides all the nutrients necessary for the micro
reproduce.
, Did each of your cultures develop at the same rate? Why might your incubation environment favor one
over another?
They did not develop at the same rate, specifically S. cerevisiae developed slower than the other two cultures.
many different factors that can influence rate of bacteria growth. Each bacteria has a different optimal environm
reproduction, with slightly different optimal temperatures or pH levels.
What is a colony and how does a colony relate to a bacterial cell? Why are colonies important in the st
microbiology?
A colony is a mass of cells that all are derived from the same original cell, one colony is made up of an entire g
bacterial cells. Colonies are important because they allow researchers to grow larger samples of a specific str
bacteria from a single cell, which allows them to more easily study one individual strain.
Are bacteria easier to observe on a plate or in a broth? How do the bacteria look on the plate as compa
broth?
Bacteria are easier to observe on a plate than in broth. On a plate you are able to identify individual colonies, a
see differences in the morphology of those colonies (such as shape, margin, elevation, and size). In broth how
only able to identify more basic evidence of bacterial growth, such as turbidity and flocculent growth.
How could you tell if one of the colonies on your pure plate was a contaminant from the environment a
come from your original culture?
