Microbiology Lab: Oil Extraction and Distillation

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Questions and Answers

What is the purpose of anhydrous sodium sulphate in the experiment?

To change the color of the oil
To dry the oil (correct)
To separate oil from water
To increase the boiling point of the oil

When did the distillation process stop?

When the oil changed color
When there was no more difference in successive readings of the oil volume (correct)
When the oil reached a certain pressure
When the oil reached a certain temperature

What was drained off after the distillation process?

The sodium sulphate
Water
The apparatus
The oil (correct)

What is the brand of the anhydrous sodium sulphate used in the experiment?

BDH (D) Signup and view all the answers

What is the purpose of distillation in this experiment?

To separate the oil from its impurities (D) Signup and view all the answers

What is the most important safety precaution when working with chloroform?

Working under a hood with proper ventilation (B) Signup and view all the answers

Why should you not breathe in chloroform fumes?

Because they can be harmful if inhaled (A) Signup and view all the answers

What is the purpose of using a hood when working with chloroform?

To prevent inhalation of vapors (A) Signup and view all the answers

What is a potential hazard when working with chloroform?

Inhalation of vapors (B) Signup and view all the answers

Why is it important to follow safety protocols when working with chloroform?

To prevent accidents (D) Signup and view all the answers

What is the purpose of using Escherichia coli ATCC 35218 and Staphylococcus aureus ATCC 25923 in the assays?

To act as control strains in the assays (C) Signup and view all the answers

What type of bacteria is Escherichia coli ATCC 35218?

Gram-negative bacteria (B) Signup and view all the answers

What is the significance of the ATCC number in the names of the bacteria?

It is a unique identifier for the bacterial strain (A) Signup and view all the answers

What is the role of Staphylococcus aureus ATCC 25923 in the assays?

It is used as a standard against which other samples can be compared (D) Signup and view all the answers

Why are control strains necessary in assays?

To provide a standard against which other samples can be compared (D) Signup and view all the answers

What was the purpose of plotting the zone diameter against the log concentration of the extract?

To determine the minimum inhibitory concentration (MIC) of the extract (A) Signup and view all the answers

Who is credited with describing the method of obtaining the MIC from the graph?

Lamikanra (D) Signup and view all the answers

What is the independent variable in the graph plotted against the log concentration of the extract?

Log concentration of the extract (C) Signup and view all the answers

What is the unit of measurement of the log concentration of the extract?

Logarithmic units (C) Signup and view all the answers

What does the graph of zone diameter against log concentration of the extract represent?

A dose-response curve of the antimicrobial agent (D) Signup and view all the answers

What type of microorganisms were susceptible to the antimicrobial activity of the methanolic solutions?

Both Gram-positive and Gram-negative organisms (B) Signup and view all the answers

What was the solute in the solutions that exhibited antimicrobial activity?

Methanol (A) Signup and view all the answers

What is the characteristic of the microorganisms that were tested against the antimicrobial activity of the methanolic solutions?

They were a mix of Gram-positive and Gram-negative organisms (C) Signup and view all the answers

What is the significance of the antimicrobial activity of the methanolic solutions?

It implies the solution has the potential to control microbial growth (C) Signup and view all the answers

What is the state of the antimicrobial activity of the methanolic solutions against the tested microorganisms?

It was potent (A) Signup and view all the answers

Study Notes

Distillation and Oil Extraction

Distillation is continued until there is no change in successive oil volume readings.
The oil is drained and dried over anhydrous sodium sulphate (BDH).

Safety Precautions

Chloroform must be used under a hood with proper ventilation.
Breathing in chloroform fumes is not allowed.

Microorganisms Used

Escherichia coli ATCC 35218 is used as a control strain in the assays.
Staphylococcus aureus ATCC 25923 is used as a control strain in the assays.

Antimicrobial Activity

Methanolic solutions of the extract have potent antimicrobial activity against all Gram-positive and Gram-negative organisms tested.
The minimum inhibitory concentration (MIC) is obtained from the graph as described by Lamikanra (1999).

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Description

This quiz covers the procedures and safety precautions for distillation and oil extraction in a microbiology laboratory, including the use of control strains.