Eukaryotic Microbes - Lab 10 PDF

Preview

Summary

lab 10...

Description

Eukaryotic Microbes, Parasitology, and Viruses PRE-LAB QUESTIONS 1. What is a model organism, and why is Saccharomyces cerevisiae so often used as one?



A model organism is used in microbiology, molecular biology, and biochemistry labs for analysis and research. Saccharomyces cerevisiae is often used as one because its smaller in size, has a fast growth rate, low costs, safe and easy to work with. It is important for the role of yeast in many foods and drinks, such as breads, wine, and beer.

2. Research and discuss the properties of mold that make them sometimes beneficial to humans, and sometimes potentially harmful.



Mold can be both beneficial to humans and sometimes potentially harmful. The benefits from mold is the citric acid that is used in medications, such as ones that can be applied to the nervous system, help with drug testing, and cancers. The potential harms can be from aspergillus and inhaled by humans and animals which can cause serious infections and produce toxins.

3. Parasitic helminths are a major cause of disease in undeveloped countries around the world. Discuss the role that microbiologists can and have played in helping to reduce the number of infections caused by parasitic helminths as well as diagnoses and treatments.



Microbiologists can and have played a helping part to reduce the number of infections caused by parasitic helminths as well as diagnoses and treatments because they have studied the different vehicles/hosts/vectors. They have identified

©eScience Labs, 2018

Eukaryotic Microbes, Parasitology, and Viruses the characteristics of the diagnosis and how to prevent the transmission from better hygiene, vaccines, as well as proper cleaning of drinking water.

©eScience Labs, 2018

Eukaryotic Microbes, Parasitology, and Viruses EXPERIMENT 1: MOLD GROWTH ON BREAD AND FRUIT Data Tables Table 1: Experiment 1 Growth Results

Bright, Control

Day of First Visible Growth 10

Extent of Growth on Bread (Mean) 1

Extent of Growth on Apple (Mean) 2

Bright, Water

7

1

2

Bright, Sugar

10

1

2

Bright, Lemon

10

3

3

Bright, Vinegar

6

2

2

Dark, Control

0

0

0

Dark, Water

11

1

1

Dark, Sugar

0

0

0

Dark, Lemon

8

1

1

Dark, Vinegar

8

1

2

Condition

Post-Lab Questions 1. Which condition produced the most mold growth? The least? The fastest? The slowest?



The condition that produced the most mold growth was the bright lemon, and the least was the dark control. The fastest condition was the bright vinegar and the slowest was the dark water.

2. What was the purpose of examining three pieces of bread and three pieces of apple in each treatment?



The purpose of examining three pieces of bread and three pieces of apple in each treatment was to see what condition was the most favorable for the mold to grow in.

©eScience Labs, 2018

Eukaryotic Microbes, Parasitology, and Viruses 3. Based on your results, what conditions are most favorable for mold growth on bread? On apple?



Based on my results the more acidic and bright conditions were the most favorable for mold growth on both the bread and the apple.

4. Would these conditions apply to all fungal growth?



No, these conditions would not apply to all fungal growth.

5. Did you notice a difference in mold growth on the bread vs the apple? If so, what do you think might account for this difference?



There was more growth on the apple vs the bread. I think this has to due to the fact that the apple has more moisture, natural/raw sugar and wasn’t processed like the bread, which provided a better environment and nutrient for the microbial growth.

6. How would changing the type of bread (e.g. fresh from a bakery, no preservatives vs. prepackaged with preservatives) affect the results?



Changing the type of bread used to fresh baked with no preservatives vs the prepacked with preservatives would have increased the growth rate and abundance of bacteria more rapidly. The preservatives keep it from spoiling/growing mold as fast.

©eScience Labs, 2018

Eukaryotic Microbes, Parasitology, and Viruses 7. How do you think changing the temperature at which the bags were incubated affected the results?



Changing the temperature at which the bags were incubated could greatly affect the results. When the bread is at a neutral temperature the microbial growth will be more steady, if you increase the temperature it may growth more rapidly, but if you increase it too much it may kill the bacteria, and if you lower the temperatures too much it may preserve the bread more and slow the growth rate.

8. How would you test the predictions/hypotheses from Questions 6 and 7?



I would test these predictions/hypotheses with different types of bread (fresh baked and prepackaged) at different temperatures and environments.

9. Look up the pH of lemon juice and vinegar. Based on your results and your knowledge of favorable environmental conditions for fungal growth, what can you conclude about the effect of pH on growth?



Lemon juice is around a 2.0 pH while vinegar is about a 2.5 pH. This making the lemon juice more acidic and producing more growth.

10. What is the source of the mold that grew on the samples?



Penicillium is the source of the mold that grew on the samples. This mold came from both the environment and airborne from the beginning of the experiment.

©eScience Labs, 2018

Eukaryotic Microbes, Parasitology, and Viruses EXPERIMENT 2: MICROSCOPIC OBSERVATION OF SACCHAROMYCES CEREVISIAE Post-Lab Questions 1. What information/structures were you able to glean from the Gram stain that you could not get from the methylene blue stain?



I was able to glean from the gram stain if it was gram positive or negative and the morphology of the bacteria, that I could not have known from the methylene blue stain.

2. What information/structures were you able to glean from the methylene blue stain that you could not get from the Gram stain?



I was able to glean from the methylene blue stain the structure and cell wall being visible as I would not have been able to see from the gram stain.

3. Is Saccharomyces cerevisiae Gram-positive or Gram-negative? Research and describe the composition of yeast cell walls. How does the composition compare to the cell walls of Gram-positive or Gram-negative bacteria?



Cell walls of bacteria is different to Saccharomyces cerevisiae, yeast, and not gram positive or gram negative. Though the bacteria can be grouped into gram positive or gram negative, the difference being the thickness of cell walls and can be shown through staining. Thick cell walls would result into the gram positive and thin cell walls would result into gram negative peptidoglycan.

©eScience Labs, 2018...