PNB 2275 Lab 4 Exam Questions and Answers| New Update with 100% Correct Answers
3 components of a spectrophotometer light source, sample loading position, and a light
detector
How does a spectrophotometer work This machine directs beams of light of different
wavelengths through a solution of the pigment and measures the fraction of the light
transmitted at each wavelength. A graph plotting a pigment's light absorption versus
wavelength is called an absorption spectrum. The sample is held in a cuvette
Beers law A=elc
e: molar extinction coefficient
l: optical path length through sample cuvette
c = concentration of the sample
Summary of Beer's law there is a linear relationship between the concentration of solute in
a solution and the absorbance or electromagnetic radiation (light)
Which of the following can change the Absorbance of the sample measured using
spectrophotometry?
A. Optical path width
B. Concentration of sample
C. Cuvette length
D. Intensity of light B
What is absorbance measured in arbitrary units
lambda max wavelength at which a substance maximally absorbs light
, Tips for using a spectrophotometer -Make sure it is set to absorbance mode
-Calibrate the tool by zeroing the absorbance reading with a blank cuvette tube
-Must be warmed up for 10 minutes
-Wipe cuvettes with a kimwipe
Hemoglobin 4-subunit protein made up of 2 alpha and 2 beta polypeptide chains, containing
a central heme group with an associated iron ion to bind to oxygen
One molecule of hemoglobin can bind to ______ molecules of oxygen:
A. 1
B. 2
C. 3
D. 4 D
How does hemoglobin tense/relaxed states work? Once 1 subunit binds to oxygen, more
subunits are converted to the relaxed, oxygen-receptive state. Thus, the more oxygen that
binds, the more receptive the hemoglobin becomes to binding even more oxygen molecules
What type of curve is the oxygen-hemoglobin dissociation curve? sigmoidal curve
When one oxygen molecule binds to hemoglobin, the affinity of the remaining hemoglobin
subunits for oxygen is increased. This is due to which of the following?
A. Beer's Law
B. Cooperative binding
C. Increased partial pressure of oxygen
3 components of a spectrophotometer light source, sample loading position, and a light
detector
How does a spectrophotometer work This machine directs beams of light of different
wavelengths through a solution of the pigment and measures the fraction of the light
transmitted at each wavelength. A graph plotting a pigment's light absorption versus
wavelength is called an absorption spectrum. The sample is held in a cuvette
Beers law A=elc
e: molar extinction coefficient
l: optical path length through sample cuvette
c = concentration of the sample
Summary of Beer's law there is a linear relationship between the concentration of solute in
a solution and the absorbance or electromagnetic radiation (light)
Which of the following can change the Absorbance of the sample measured using
spectrophotometry?
A. Optical path width
B. Concentration of sample
C. Cuvette length
D. Intensity of light B
What is absorbance measured in arbitrary units
lambda max wavelength at which a substance maximally absorbs light
, Tips for using a spectrophotometer -Make sure it is set to absorbance mode
-Calibrate the tool by zeroing the absorbance reading with a blank cuvette tube
-Must be warmed up for 10 minutes
-Wipe cuvettes with a kimwipe
Hemoglobin 4-subunit protein made up of 2 alpha and 2 beta polypeptide chains, containing
a central heme group with an associated iron ion to bind to oxygen
One molecule of hemoglobin can bind to ______ molecules of oxygen:
A. 1
B. 2
C. 3
D. 4 D
How does hemoglobin tense/relaxed states work? Once 1 subunit binds to oxygen, more
subunits are converted to the relaxed, oxygen-receptive state. Thus, the more oxygen that
binds, the more receptive the hemoglobin becomes to binding even more oxygen molecules
What type of curve is the oxygen-hemoglobin dissociation curve? sigmoidal curve
When one oxygen molecule binds to hemoglobin, the affinity of the remaining hemoglobin
subunits for oxygen is increased. This is due to which of the following?
A. Beer's Law
B. Cooperative binding
C. Increased partial pressure of oxygen
