BIO 121 Lab Exam 1
Question 1.
the steps of calibrating a spectrophotometer.
ANSWER
1. Set wavelength to 540
2. Read = 0% T
3. Prepare solvent blank and put it in
4. Read= 100% T or 100 for Abs
5. Take out solvent blank
Question 2.
Solute
ANSWER
the substance that is dissolved
Question 3.
Solvent
ANSWER
A liquid substance capable of dissolving other substances
Question 4.
Solution
ANSWER
A mixture that forms when one substance dissolves another.
Question 5.
Transmittance
ANSWER
The passing of light through a sample
Question 6.
Absorbance
ANSWER
The amount of light absorbed by a sample
1/8
, Question 7.
how to perform a serial dilution and determine the re-sulting concentrations
ANSWER
- Create initial test
- Then take half of it and dilute that
- Continue that with the rest of the tubes
- The concentration is the continued halving of the initial test
Question 8.
how to use a standard curve to find the concentration of an "unknown" solution
ANSWER
- Graph all known points
- Create a curve from those points
- Then find the unknown point on the curve
Question 9.
difference between a log scale and a linear scale, as well as a logarithmic vs linear relationship - and as it pertains to %Transmittance
ANSWER
- A log scale should be used to represent percent changes while a linear scale should be used to show a constant change.
- % Transmittance should be shown with a log scale because it is reduced by a percentage not a constant amount
Question 10.
Test to identify sugar and what does the positive reaction look like
ANSWER
a. Benedicts
b. Yellow/orange
Question 11.
Test to identify Starch and what does the positive reaction look like
ANSWER
a. Lugols Iodine
b. Blackish
Question 12.
Test to identify Protein and what does the positive reaction look like
ANSWER
a. Biurets reagent
b. Violent pink
Question 13.
Test to identify Fats and what does the positive reaction look like
ANSWER
a. Sudan IV
b. Red globules
2/8
Question 1.
the steps of calibrating a spectrophotometer.
ANSWER
1. Set wavelength to 540
2. Read = 0% T
3. Prepare solvent blank and put it in
4. Read= 100% T or 100 for Abs
5. Take out solvent blank
Question 2.
Solute
ANSWER
the substance that is dissolved
Question 3.
Solvent
ANSWER
A liquid substance capable of dissolving other substances
Question 4.
Solution
ANSWER
A mixture that forms when one substance dissolves another.
Question 5.
Transmittance
ANSWER
The passing of light through a sample
Question 6.
Absorbance
ANSWER
The amount of light absorbed by a sample
1/8
, Question 7.
how to perform a serial dilution and determine the re-sulting concentrations
ANSWER
- Create initial test
- Then take half of it and dilute that
- Continue that with the rest of the tubes
- The concentration is the continued halving of the initial test
Question 8.
how to use a standard curve to find the concentration of an "unknown" solution
ANSWER
- Graph all known points
- Create a curve from those points
- Then find the unknown point on the curve
Question 9.
difference between a log scale and a linear scale, as well as a logarithmic vs linear relationship - and as it pertains to %Transmittance
ANSWER
- A log scale should be used to represent percent changes while a linear scale should be used to show a constant change.
- % Transmittance should be shown with a log scale because it is reduced by a percentage not a constant amount
Question 10.
Test to identify sugar and what does the positive reaction look like
ANSWER
a. Benedicts
b. Yellow/orange
Question 11.
Test to identify Starch and what does the positive reaction look like
ANSWER
a. Lugols Iodine
b. Blackish
Question 12.
Test to identify Protein and what does the positive reaction look like
ANSWER
a. Biurets reagent
b. Violent pink
Question 13.
Test to identify Fats and what does the positive reaction look like
ANSWER
a. Sudan IV
b. Red globules
2/8
