bioc LAT2 Questions and Answers
Select the BEST answer.
The percentage oxyhaemoglobin in a haemoglobin solution can be calculated by:
using the ratio of absorbances of oxy- and deoxyhaemoglobin at wavelengths where
the biggest difference in absorbance readings are observed between the two forms.
adding a live yeast suspension to an oxyhaemoglobin solution and observe the
change in absorbance by spectrophotometry.
measuring the absorbance of an oxyhaemoglobin solution using the wavelength that
corresponds to its absorption maxima and then apply the Beer-Lambert formula.
measuring the absorbance of a haemoglobin solition at 560 nm, which is
deoxyhaemoglobin's absorption maxima and the wavelenth where oxyhaemoglobin
absorb light the weakest.
✓ ~~~using the ratio of absorbances of oxy- and deoxyhaemoglobin at wavelengths where
the biggest difference in absorbance readings are observed between the two forms.
Absorbance may be defined as:
the ratio of lightpath length to incident light
,the log of the ratio of incident light to transmitted light
the ratio of concentration to transmitted light
the ratio of molar absorbance coefficient to lightpath length
✓ ~~~the log of the ratio of incident light to transmitted light
Beer's Law implies that:
the concentration of a solution is dependent on lightpath length
the distance light travels through a solution is independent of concentration
the molar absorbance coefficient is dependent on the concentration of the absorbing
solute
the absorption of light increases with increasing solute concentration
✓ ~~~the absorption of light increases with increasing solute concentration
When haemoglobin in oxygenated in the lungs it is most likely to:
, ✓ ~~~
A 3 mL cuvette was filled with 0.5 mL of solution Y and 2.5 mL of water and its
absorbance at 340 nm was 0.394.
The molar absorbance coefficient of solution Y is 31,000 L/mol/cm. The pathlength is
1 cm.
What is the concentration of the diluted solution Y?
Express your answer in μM and with two decimal points.
✓ ~~~12.71
A spectrophotometric experiment yields the following data of a 1 in 3 diluted sample:
c = 2.3 mM
A = 0.46
l = 5 mm
wavelength = 480nm
What is the molar absorbance coefficient of the compound that was tested?
Provide your answer to the nearest whole number. Units are not required
✓ ~~~400
Solution A had an initial concentration of 80mg/mL and after it had been diluted it
had a concentration of 4mg/mL. Which statement is INCORRECT regarding this
dilution?
Select the BEST answer.
The percentage oxyhaemoglobin in a haemoglobin solution can be calculated by:
using the ratio of absorbances of oxy- and deoxyhaemoglobin at wavelengths where
the biggest difference in absorbance readings are observed between the two forms.
adding a live yeast suspension to an oxyhaemoglobin solution and observe the
change in absorbance by spectrophotometry.
measuring the absorbance of an oxyhaemoglobin solution using the wavelength that
corresponds to its absorption maxima and then apply the Beer-Lambert formula.
measuring the absorbance of a haemoglobin solition at 560 nm, which is
deoxyhaemoglobin's absorption maxima and the wavelenth where oxyhaemoglobin
absorb light the weakest.
✓ ~~~using the ratio of absorbances of oxy- and deoxyhaemoglobin at wavelengths where
the biggest difference in absorbance readings are observed between the two forms.
Absorbance may be defined as:
the ratio of lightpath length to incident light
,the log of the ratio of incident light to transmitted light
the ratio of concentration to transmitted light
the ratio of molar absorbance coefficient to lightpath length
✓ ~~~the log of the ratio of incident light to transmitted light
Beer's Law implies that:
the concentration of a solution is dependent on lightpath length
the distance light travels through a solution is independent of concentration
the molar absorbance coefficient is dependent on the concentration of the absorbing
solute
the absorption of light increases with increasing solute concentration
✓ ~~~the absorption of light increases with increasing solute concentration
When haemoglobin in oxygenated in the lungs it is most likely to:
, ✓ ~~~
A 3 mL cuvette was filled with 0.5 mL of solution Y and 2.5 mL of water and its
absorbance at 340 nm was 0.394.
The molar absorbance coefficient of solution Y is 31,000 L/mol/cm. The pathlength is
1 cm.
What is the concentration of the diluted solution Y?
Express your answer in μM and with two decimal points.
✓ ~~~12.71
A spectrophotometric experiment yields the following data of a 1 in 3 diluted sample:
c = 2.3 mM
A = 0.46
l = 5 mm
wavelength = 480nm
What is the molar absorbance coefficient of the compound that was tested?
Provide your answer to the nearest whole number. Units are not required
✓ ~~~400
Solution A had an initial concentration of 80mg/mL and after it had been diluted it
had a concentration of 4mg/mL. Which statement is INCORRECT regarding this
dilution?
