BIO 107 LAB FINAL TEST YOURSELF
QUESTIONS AND ANSWERS
What are three types of lenses on a light microscope? - Correct Answers -- Condenser
lens
- Objective lens
- Ocular lens
Condenser lens - Correct Answers -focuses light on the specimen
Objective lens - Correct Answers -magnifies the image
Ocular lens - Correct Answers -magnifies and inverts the image for viewing
Reducing the amount of light will improve ________________ - Correct Answers -
contrast
Switching from a 40X objective lens (40/0.65) to 100X lens (100/1.25) will improve
_______________ and __________________ - Correct Answers -magnification and
resolution
Using immersion oil will improve __________________ - Correct Answers -resolution
Switching 10X ocular lens with 15X ocular lens (identical objective lenses) will improve
__________________ - Correct Answers -magnification
Staining the specimen will improve __________________ - Correct Answers -contrast
Changing the light source from a 400 nm light to a 500 nm light will improve
__________________ - Correct Answers -nothing
Changing the light source from a 500 nm light to a 400 nm light will improve
__________________ - Correct Answers -resolution
For Lab 2, you were told to use distilled water as the "blank" to calibrate the
spectrophotometer. Briefly explain why distilled water was used - Correct Answers -A
"blank" test tube contains all the components of the sample being measured except the
molecule of interest. In this experiment distilled water is used as the "blank" because
, betacyanin stock solution is betacyanin in distilled water and the beet root discs will be
place in distilled water to collect the betacyanin pigment
You have been asked to determine the concentration of a Pigment X solution. After
calibrating the machine, you place 5 ml of solution into the spectrophotometer and
obtain an absorbance reading of 2.0. Since this absorbance value does not fall within
the values of the standard curve, you dilute 8 ml of the original sample into 72 ml of
water. You measure the absorbance of the diluted sample to be 0.4. - Correct Answers -
Cd= 8µM D= 8ml / (8+72 ml)=8/80=0.1 Cu=Cd/D = 8µM/0.1=80µM
Your TA gave you a stock solution of chlorophyll, a pigment found in plant cells. Can
you use the standard curve for betacyanin to determine the concentration of this stock
solution? Briefly explain why or why not. - Correct Answers -No, because a standard
curve is specific to the pigment and its buffer.
Fluid Mosaic - Correct Answers -Describes the structure of the plasma membrane as a
mosaic of components —including phospholipids, cholesterol, proteins, and
carbohydrates—that gives the membrane a fluid character.
Phospholipid bilayer - Correct Answers -A thin polar membrane made of two layers of
lipid molecules. These membranes are flat sheets that form a continuous barrier around
all cells. The cell membranes of almost all organisms and many viruses are made of a
lipid bilayer. Phospholipids consist of a hydrophilic (or 'water loving') head and a
hydrophobic (or 'water fearing') tail. Phospholipids like to line up and arrange
themselves into two parallel layers
Are the yeast in the Durham tube undergoing aerobic respiration, anaerobic respiration,
or fermentation? Briefly explain your answer. - Correct Answers -It is undergoing
fermentation. This strain of yeast is significant because it metabolizes glucose using
fermentative pathways, even in the presence of oxygen.
What 2 properties of DNA allowed you to separate genomic DNA from plasmid DNA? -
Correct Answers -- Plasmid DNA is supercoiled so the DNA helix do not move far apart,
but genomic DNA does
- Genomic DNA is longer and causes the lysate to become viscous after solution II
In lab 8, your other lab partner accidentally vortexed the tube after adding solution II. If
your lab partner finished the remainder of the lab as written, what cellular components
would be present in the tube at the end of the lab? - Correct Answers -It would contain
plasmid DNA, RNA and genomic DNA that had been sheared into small pieces
True or False: Solution A and solution B have transmittance values of 70% and 25%
respectively. Therefore, solution B is lighter in colour than solution A. - Correct Answers
-False. B is darker than A.
QUESTIONS AND ANSWERS
What are three types of lenses on a light microscope? - Correct Answers -- Condenser
lens
- Objective lens
- Ocular lens
Condenser lens - Correct Answers -focuses light on the specimen
Objective lens - Correct Answers -magnifies the image
Ocular lens - Correct Answers -magnifies and inverts the image for viewing
Reducing the amount of light will improve ________________ - Correct Answers -
contrast
Switching from a 40X objective lens (40/0.65) to 100X lens (100/1.25) will improve
_______________ and __________________ - Correct Answers -magnification and
resolution
Using immersion oil will improve __________________ - Correct Answers -resolution
Switching 10X ocular lens with 15X ocular lens (identical objective lenses) will improve
__________________ - Correct Answers -magnification
Staining the specimen will improve __________________ - Correct Answers -contrast
Changing the light source from a 400 nm light to a 500 nm light will improve
__________________ - Correct Answers -nothing
Changing the light source from a 500 nm light to a 400 nm light will improve
__________________ - Correct Answers -resolution
For Lab 2, you were told to use distilled water as the "blank" to calibrate the
spectrophotometer. Briefly explain why distilled water was used - Correct Answers -A
"blank" test tube contains all the components of the sample being measured except the
molecule of interest. In this experiment distilled water is used as the "blank" because
, betacyanin stock solution is betacyanin in distilled water and the beet root discs will be
place in distilled water to collect the betacyanin pigment
You have been asked to determine the concentration of a Pigment X solution. After
calibrating the machine, you place 5 ml of solution into the spectrophotometer and
obtain an absorbance reading of 2.0. Since this absorbance value does not fall within
the values of the standard curve, you dilute 8 ml of the original sample into 72 ml of
water. You measure the absorbance of the diluted sample to be 0.4. - Correct Answers -
Cd= 8µM D= 8ml / (8+72 ml)=8/80=0.1 Cu=Cd/D = 8µM/0.1=80µM
Your TA gave you a stock solution of chlorophyll, a pigment found in plant cells. Can
you use the standard curve for betacyanin to determine the concentration of this stock
solution? Briefly explain why or why not. - Correct Answers -No, because a standard
curve is specific to the pigment and its buffer.
Fluid Mosaic - Correct Answers -Describes the structure of the plasma membrane as a
mosaic of components —including phospholipids, cholesterol, proteins, and
carbohydrates—that gives the membrane a fluid character.
Phospholipid bilayer - Correct Answers -A thin polar membrane made of two layers of
lipid molecules. These membranes are flat sheets that form a continuous barrier around
all cells. The cell membranes of almost all organisms and many viruses are made of a
lipid bilayer. Phospholipids consist of a hydrophilic (or 'water loving') head and a
hydrophobic (or 'water fearing') tail. Phospholipids like to line up and arrange
themselves into two parallel layers
Are the yeast in the Durham tube undergoing aerobic respiration, anaerobic respiration,
or fermentation? Briefly explain your answer. - Correct Answers -It is undergoing
fermentation. This strain of yeast is significant because it metabolizes glucose using
fermentative pathways, even in the presence of oxygen.
What 2 properties of DNA allowed you to separate genomic DNA from plasmid DNA? -
Correct Answers -- Plasmid DNA is supercoiled so the DNA helix do not move far apart,
but genomic DNA does
- Genomic DNA is longer and causes the lysate to become viscous after solution II
In lab 8, your other lab partner accidentally vortexed the tube after adding solution II. If
your lab partner finished the remainder of the lab as written, what cellular components
would be present in the tube at the end of the lab? - Correct Answers -It would contain
plasmid DNA, RNA and genomic DNA that had been sheared into small pieces
True or False: Solution A and solution B have transmittance values of 70% and 25%
respectively. Therefore, solution B is lighter in colour than solution A. - Correct Answers
-False. B is darker than A.
