Physiology - BIO 151 - Lab Exam Questions
and Correct Answers, With Complete Solution.
2024.
Lab 1 Title
Scientific Method
What are the 5 steps of the Scientific Method?
Observation, Generation of Hypothesis, Testing of Hypothesis, Presentation, and
analysis of data, Conclusion
What is an independent variable
- Variable that cant be changed
dependent variable
what you measure during an experiment - depends on the independent variable/ subject
What are controlled variables
Other variables/factors that may affect the dependent variables (outcome)
Why are control variables necessary
so that the effects of the independent variable can truly be tested
Which variables will be placed on which axis of the graph?
The independent variable will be on the X-axis, the dependent variable will be on the y-
axis
Lab 2 title
Introduction to chemical concepts
What were the major concepts viewed in lab 2
-Metric Measurement, Brownian Movement Osmosis, Diffusion, Buffers, Hypotonic,
Hypertonic, and Isotonic Solutions.
What is a nanometer, and what is this measurement used for?
1 meter = 1x10^9 = 0.000000001 nm (measures atoms)
what is a micrometer, and what is this measurement used for?
1 meter = 1x 10^6 = 0.000001 um (measures cells)
what is a millimeter, and what is this measurement used for?
1 meter = 1x 10^3mm = 0.001 mm
what is a centimeter, and what is this measurement used for?
1 meter = 1x 10^2mm = 0.01 cm
What is the Brownian movement, and why is it relevant?
atoms, ions, and molecules are in constant motion and colliding with each other, it is the
driving force for osmosis and diffusion.
What increases the rate of movement of particles?
Increase in temperature, or an increase in concentration.
What is the difference between a solute and solvent?
Solute = a soluble substance (what will be dissolved)
Solvent = a liquid (solution) what will dissolve the solute
How was Diffusion across a synthetic membrane observed, and what was the
outcome?
,Through the use of a dialysis bag. the bag contained starch solution. the dialysis bag
was then weighed and placed in water with iodine potassium iodide drops. after an hour
the bag was weighed again. The bag should have increased in weight due to osmosis.
However, diffusion should not have occurred. if diffusion had occurred the starch would
have leaked from the bag causing the iodine to go blue.
what is osmosis
The diffusion of water through a differentially permeable membrane- from an area of low
to high concentration (towards a solute). was observed by adding various
concentrations of NaCl to sheeps blood
what is diffusion
The movement of particles from an area of high to low concentration
what is the difference between isotonic, hypotonic, and hypertonic solutions
isotonic = equal amounts of solute inside as outside of the cell
hypertonic = more solute on the outside of the cell compared to inside
hypotonic = more solute on the inside compared to outside of the cell
What is the expected outcome of RBC's when placed in
Isotonic/hypertonic/hypotonic solutions?
Isotonic = healthy, net movement of particles inside and outside of cell (0.9 % NaCl)
hypertonic = crenated, cell shrivels up -water rushed out of cell ( 5.0% NaCl)
hypotonic = lysed, cell swells up and bursts - water rushes into cell. (0% NaCl)
what is the difference between an acid and a base?
Acid = substance that releases H+ ions as it dissolves
Base = substance that releases OH- ions or absorbs H+ ions as it dissolves.
What does a buffer do and what is an example of one?
A buffer can either absorb or release H+ ions to maintain pH/ balance changes in pH
due to acids or bases being added. Water is a buffer but will become acidic as more
acid is added (lower pH). Sodium Bicarbonate (NaHCO3) is a stronger buffer and it will
prevent acidity
Lab 3 title
Digestion of Organic Macromolecules
What was the purpose of Lab 3?
- To monitor the activity of digestive enzymes,
- To evaluate the substrates and products of the reactions catalyzed by digestive
enzyme.
- To review the function of various enzymes
- To evaluate factors that affect the activity of various digestive enzymes.
what is a substrate?
the substance on which an enzyme acts on
what is the function of a digestive enzyme?
To lower the activation energy of biological reactions and to hydrolyze covalent bonds of
food. (protein)
What was used to observe the effects of Salivary Amylase?
- Benedict's reagent was used on 6 test tubes, it turns blue when there are no sugars
present, and it turns yellow/orange when sugars (di/monosaccharides) are present.
- allows us to see if salivary amylase was able to break down polysaccharides.
What is the expected outcome of salivary amylase on starch and cellulose?
, Salivary amylase was expected to break down (hydrolyze) starch into sugars
(di/monosaccharides) turning the test tube yellow. It was expected to have no effect on
cellulose since it is a polysaccharide and cannot be broken down, the test tube remains
blue.
what is the function of the enzyme pepsin, and what is its optimum pH?
Pepsin is an enzyme that breaks down proteins into peptides. It has an optimum pH of
2-4 and will work best in that range. normal pH optimum is 6-8
How were the effects of the enzyme Pepsin Observed?
Biurets Reagent was used to observe pepsin.
- turns blue when there are no proteins/peptides.
- turns purple when proteins are present
- turns pink when peptides are present
What is the expected outcome of Pepsin on effect on proteins?
Pepsin will be able to break down proteins when it's in its optimum pH (low pH) and
therefore the Biurets reagent will turn pink (peptides will be present). In the test tubes
with higher pH the pepsin won't function as well and won't break down the proteins -
Biurets reagent will turn purple. The test tube with no protein will turn blue.
What is emulsification, and what is an example of an emulsifier?
taking fat molecules and breaking them into smaller molecules, enabling them to be
grabbed ahold of (speeds up hydrolysis of lipids) - disperses water-insoluble lipids in
aqueous solutions.
-Bile is an emulsifier.
what is released during Hydrolysis of fats?
Fatty acids are released - lowering the pH of the solution and making it more acidic.
How were the effects of bile and lipase on the digestion of fat observed?
phenolphthalein = a pH indicator that is colorless in neutral/ acidic conditions, but pink in
presence of a base was added to 3 test tubes along with the cream. If emulsification
occurs, the test tubes will go from pink to white ( goes from basic to acidic as hydrolysis
of fat occurs.)
What was the expected outcome of adding bile and lipase to the cream solutions?
- cream and water were expected to stay pink (no emulsification)
- Cream and lipase slowly go white (emulsification occurs but slowly)
-cream, lipase, and bile quickly go white (emulsification happens fast).
What is the title of Lab 4
Cellular Respiration and Glucose Monitoring
What was the purpose of lab 4?
Part 1:
-to demonstrate the fermentation of sugar by yeast
- to determine which sugars yeast can ferment and to what extent
- to understand the importance of experimental controls
- to understand what is meant by controlled variable, independent variable, and
dependent variable.
Part 2:
- To measure the range of blood sugars in the class
- To understand what diabetes is and how types 1 and 2 are different
- To understand the clinical significance of the various tests for diabetes.
and Correct Answers, With Complete Solution.
2024.
Lab 1 Title
Scientific Method
What are the 5 steps of the Scientific Method?
Observation, Generation of Hypothesis, Testing of Hypothesis, Presentation, and
analysis of data, Conclusion
What is an independent variable
- Variable that cant be changed
dependent variable
what you measure during an experiment - depends on the independent variable/ subject
What are controlled variables
Other variables/factors that may affect the dependent variables (outcome)
Why are control variables necessary
so that the effects of the independent variable can truly be tested
Which variables will be placed on which axis of the graph?
The independent variable will be on the X-axis, the dependent variable will be on the y-
axis
Lab 2 title
Introduction to chemical concepts
What were the major concepts viewed in lab 2
-Metric Measurement, Brownian Movement Osmosis, Diffusion, Buffers, Hypotonic,
Hypertonic, and Isotonic Solutions.
What is a nanometer, and what is this measurement used for?
1 meter = 1x10^9 = 0.000000001 nm (measures atoms)
what is a micrometer, and what is this measurement used for?
1 meter = 1x 10^6 = 0.000001 um (measures cells)
what is a millimeter, and what is this measurement used for?
1 meter = 1x 10^3mm = 0.001 mm
what is a centimeter, and what is this measurement used for?
1 meter = 1x 10^2mm = 0.01 cm
What is the Brownian movement, and why is it relevant?
atoms, ions, and molecules are in constant motion and colliding with each other, it is the
driving force for osmosis and diffusion.
What increases the rate of movement of particles?
Increase in temperature, or an increase in concentration.
What is the difference between a solute and solvent?
Solute = a soluble substance (what will be dissolved)
Solvent = a liquid (solution) what will dissolve the solute
How was Diffusion across a synthetic membrane observed, and what was the
outcome?
,Through the use of a dialysis bag. the bag contained starch solution. the dialysis bag
was then weighed and placed in water with iodine potassium iodide drops. after an hour
the bag was weighed again. The bag should have increased in weight due to osmosis.
However, diffusion should not have occurred. if diffusion had occurred the starch would
have leaked from the bag causing the iodine to go blue.
what is osmosis
The diffusion of water through a differentially permeable membrane- from an area of low
to high concentration (towards a solute). was observed by adding various
concentrations of NaCl to sheeps blood
what is diffusion
The movement of particles from an area of high to low concentration
what is the difference between isotonic, hypotonic, and hypertonic solutions
isotonic = equal amounts of solute inside as outside of the cell
hypertonic = more solute on the outside of the cell compared to inside
hypotonic = more solute on the inside compared to outside of the cell
What is the expected outcome of RBC's when placed in
Isotonic/hypertonic/hypotonic solutions?
Isotonic = healthy, net movement of particles inside and outside of cell (0.9 % NaCl)
hypertonic = crenated, cell shrivels up -water rushed out of cell ( 5.0% NaCl)
hypotonic = lysed, cell swells up and bursts - water rushes into cell. (0% NaCl)
what is the difference between an acid and a base?
Acid = substance that releases H+ ions as it dissolves
Base = substance that releases OH- ions or absorbs H+ ions as it dissolves.
What does a buffer do and what is an example of one?
A buffer can either absorb or release H+ ions to maintain pH/ balance changes in pH
due to acids or bases being added. Water is a buffer but will become acidic as more
acid is added (lower pH). Sodium Bicarbonate (NaHCO3) is a stronger buffer and it will
prevent acidity
Lab 3 title
Digestion of Organic Macromolecules
What was the purpose of Lab 3?
- To monitor the activity of digestive enzymes,
- To evaluate the substrates and products of the reactions catalyzed by digestive
enzyme.
- To review the function of various enzymes
- To evaluate factors that affect the activity of various digestive enzymes.
what is a substrate?
the substance on which an enzyme acts on
what is the function of a digestive enzyme?
To lower the activation energy of biological reactions and to hydrolyze covalent bonds of
food. (protein)
What was used to observe the effects of Salivary Amylase?
- Benedict's reagent was used on 6 test tubes, it turns blue when there are no sugars
present, and it turns yellow/orange when sugars (di/monosaccharides) are present.
- allows us to see if salivary amylase was able to break down polysaccharides.
What is the expected outcome of salivary amylase on starch and cellulose?
, Salivary amylase was expected to break down (hydrolyze) starch into sugars
(di/monosaccharides) turning the test tube yellow. It was expected to have no effect on
cellulose since it is a polysaccharide and cannot be broken down, the test tube remains
blue.
what is the function of the enzyme pepsin, and what is its optimum pH?
Pepsin is an enzyme that breaks down proteins into peptides. It has an optimum pH of
2-4 and will work best in that range. normal pH optimum is 6-8
How were the effects of the enzyme Pepsin Observed?
Biurets Reagent was used to observe pepsin.
- turns blue when there are no proteins/peptides.
- turns purple when proteins are present
- turns pink when peptides are present
What is the expected outcome of Pepsin on effect on proteins?
Pepsin will be able to break down proteins when it's in its optimum pH (low pH) and
therefore the Biurets reagent will turn pink (peptides will be present). In the test tubes
with higher pH the pepsin won't function as well and won't break down the proteins -
Biurets reagent will turn purple. The test tube with no protein will turn blue.
What is emulsification, and what is an example of an emulsifier?
taking fat molecules and breaking them into smaller molecules, enabling them to be
grabbed ahold of (speeds up hydrolysis of lipids) - disperses water-insoluble lipids in
aqueous solutions.
-Bile is an emulsifier.
what is released during Hydrolysis of fats?
Fatty acids are released - lowering the pH of the solution and making it more acidic.
How were the effects of bile and lipase on the digestion of fat observed?
phenolphthalein = a pH indicator that is colorless in neutral/ acidic conditions, but pink in
presence of a base was added to 3 test tubes along with the cream. If emulsification
occurs, the test tubes will go from pink to white ( goes from basic to acidic as hydrolysis
of fat occurs.)
What was the expected outcome of adding bile and lipase to the cream solutions?
- cream and water were expected to stay pink (no emulsification)
- Cream and lipase slowly go white (emulsification occurs but slowly)
-cream, lipase, and bile quickly go white (emulsification happens fast).
What is the title of Lab 4
Cellular Respiration and Glucose Monitoring
What was the purpose of lab 4?
Part 1:
-to demonstrate the fermentation of sugar by yeast
- to determine which sugars yeast can ferment and to what extent
- to understand the importance of experimental controls
- to understand what is meant by controlled variable, independent variable, and
dependent variable.
Part 2:
- To measure the range of blood sugars in the class
- To understand what diabetes is and how types 1 and 2 are different
- To understand the clinical significance of the various tests for diabetes.
