BIO 2301 LAB EXAM QUESTIONS WITH
VERIFIED ANSWERS
Do solutes of differing masses diffuse at the same rates if concentration gradients
are the same? - ANSWER-No. Smaller solutes diffuse faster than large ones for any
given concentration gradient. This is shown in Table 3 of the spreadsheet and its
graph.
If multiple solutes are present and diffusing, do they diffuse independently or do they
influence one another's diffusion? - ANSWER-They diffuse independently. This is
demonstrated in Table 4 of the spreadsheet. Note that the diffusion rates for each
solute are unaffected by the presence of the other solute.
In facilitated diffusion, what determines the rate of diffusion: the concentration
gradient or the number of carriers? - ANSWER-The sloping lines in the graph of the
data from Table 5 of the spreadsheet indicate that the concentration gradient is
affecting the diffusion rates. The fact that the three lines are separate from one
another suggests that the number of carriers is also affecting diffusion rates. Thus,
the answer is both. (It is worthy of note that in many practical applications the
number of carriers will be vastly smaller than the number of carriers. Because of this,
changes in the number of carriers will typically have a more significant impact on the
diffusion rates in most "real world" applications).
What kinds of osmotic effects do you expect hypo-, hyper-, and iso-tonic solutions to
have on a cell? - ANSWER-Hypotonic solutions will cause water to be drawn into a
cell by osmosis, leading to lysis of the cell, isotonic solutions will cause no net
movement of water by osmosis, hypertonic solutions will cause water to be drawn
out of the cell by osmosis, leading to crenation of the cell.
Remember that penetrating solutes have no osmotic effect and that cells have an
osmolarity of 300 mOsmolar. What effect does a 300 mOsmolar solution of a
nonpenetrating solute have on a cell, and how does this differ from the effect of a
300 mOsmolar solution of a penetrating solute? - ANSWER-A solution of 300
mOsmoles of nonpenetrating solutes matches the tonicity of a cell and, therefore will
cause no net movement of water by osmosis. In contrast, a solution of 300
mOsmoles of a penetrating solute has a tonicity of zero (because penetrating solutes
have no osmotic effect). Therefore, placing a cell into a solution of 300 mOsmoles of
a penetrating solute would be the equivalent of placing the cell into distilled water.
The solution is hypotonic and would cause lysis of the cell. This effect of placing cells
into a 300 mOsmolar solution of a nonpenetrating was demonstrated with the 0.15M
sodium chloride and the 0.30 M glucose solutions. The effect of placing cells into a
300 mOsmolar solution of a penetrating solute was demonstrated with the 0.15 M
ammonium chloride solution and the 0.30 M urea solution.
List 3 methods used in today's lab to assess heart rate. - ANSWER-Palpation, PPG
and ECG.
,A difference between the palpated heart rate and the heart rate calculated by
auscultation is termed a - ANSWER-pulse deficit
Why is it important that the subject not know when the respiratory rate is being
assessed. - ANSWER-It can alter the true "normal" breathing pattern. If a subject
knows they are being measured or evaluated, they may unconsciously behave
differently and values may not be as accurate.
What is the difference between assessing blood pressure by auscultation and
assessing blood pressure by palpation? - ANSWER-Both use a sphygmomanometer
but auscultation uses a stethoscope over the brachial artery, whereby palpation
involves no stethoscope and palpation of the brachial or radial artery.
Where on the subject is the respiratory transducer placed? - ANSWER-around chest
TRUE or FALSE. When assessing blood pressure by palpation, it is very easy to
determine diastolic pressure. - ANSWER-false
Based upon your observations what are some of the advantages and disadvantages
of assessing heart rate by each of these methods under different circumstances? -
ANSWER-EKG and PPG can determine accurate heart rates and require little skill to
produce good measurements. Unfortunately, they are both unreliable if the subject is
moving.
Counting a radial pulse is accurate but requires skill on the part of the individual
doing the measurement. Because of the time required to count a pulse, changes in
heart rate that occur only briefly cannot be detected by this method.
Initially there is a high concentration of sodium on the left side of a beaker of water.
What is likely to happen (with regard to movement of ions and/or water) in this
beaker? - ANSWER-It will disperse until equilibrium is achieved and sodium is
equally distributed throughout the beaker.
What is the proper term for the process that is occurring in the beaker described
above? - ANSWER-Diffusion of a solute from a higher concentration to a lower
concentration.
A red blood cell is surrounded by a solution containing a higher concentration of
solutes than found inside of the cell. Cell membranes act a selectively permeable
membranes. What will happen to this cell? - ANSWER-The red blood cell will crenate
or shrink since it will lose water to the to the solution. Solutes will go. from a higher
concentration to a lower concentration.
What is meant by the term hypotonic solutions, and what effect would this type of
solution have on a cell? - ANSWER-There is a lower concentration of solutes (more
water) in the hypertonic solution compared to the cell. The cell would swell and lyse,
since water is going to move into it to equal concentrations on both sides.
, How is tonicity different than osmolarity? - ANSWER-Osmolarity is the concentration
of solutes in a solution. Tonicity refers to the non-penetrating solutes. In order to
determine tonicity, osmolarity is calculated.
The presence of a sloping line on a graph suggest what about the relationship
between the variable on the x-axis, and the variable on the y-axis? - ANSWER-The
sloping line between the variables on the x-axis and y-axis means the two variables
show a correlation. A positive sloping line ( / ) means there is a direct correlation,
whereby a sloping line that has a negative slope would have an indirect correlation.
Does the rate of diffusion change as the concentration gradient changes? -
ANSWER-Yes. An increase in the concentration gradient causes an increase in the
diffusion rate. The sloping line in the first graph is evidence of this relationship.
2. How do concentration gradients affect the direction of diffusion? - ANSWER-
Molecules diffuse from areas of high concentration to areas of low concentration.
Reversing the gradient will reverse the direction of the diffusions. This effect is
demonstrated in Table 2 of the spreadsheet and its graph.
Which method(s) would be the best at detecting heart rate changes that occur for
only a few seconds such as those expected as one stands? - ANSWER-The EKG or
PPG could be employed in this circumstance.
Which method(s) would be the most useful for a subject that is moving (such as
during exercise)? - ANSWER-Counting a radial pulse would be the most accurate
method in this instance because of the sensitivity of the EKG and PPG to movement.
Which is the most readily available in non-clinical settings? - ANSWER-With a watch,
a radial pulse can be counted in almost all settings.
Contrast the accuracy of these methods? - ANSWER-The relative accuracy of these
methods is somewhat context dependent. If the subject is moving, counting a radial
pulse is the most accurate alternative. However, if the patient is still the EKG and
PPG can provided more accurate measurements.
"Pulse deficit" describes a difference between pulse rate assessed by palpating a
radial pulse and heart rate assessed by auscultation (listening) or EKG. What could
account for pulse deficit? - ANSWER-Remember that the EKG is detecting electrical
activity of the heart, and auscultation is detecting the closing of the heart valves.
Neither of these directly measures the movement of the blood. Thus, if the heart is
not effective in moving blood with each beat (as could be the case with a severely
leaky valve), a pulse deficit could result.
An apparent pulse deficit may also occur if the individual making the measurement is
not skillful and, therefore, "misses" some of the pulses at the wrist.
How does blood pressure affect the plethysmography data? Does this influence
pulse rate assessment by this method? - ANSWER-Because the plethysmograph
measures the amount of blood under the skin, and increase in blood pressure would
tend to cause an increase in the amplitude of the waveform seen on the
VERIFIED ANSWERS
Do solutes of differing masses diffuse at the same rates if concentration gradients
are the same? - ANSWER-No. Smaller solutes diffuse faster than large ones for any
given concentration gradient. This is shown in Table 3 of the spreadsheet and its
graph.
If multiple solutes are present and diffusing, do they diffuse independently or do they
influence one another's diffusion? - ANSWER-They diffuse independently. This is
demonstrated in Table 4 of the spreadsheet. Note that the diffusion rates for each
solute are unaffected by the presence of the other solute.
In facilitated diffusion, what determines the rate of diffusion: the concentration
gradient or the number of carriers? - ANSWER-The sloping lines in the graph of the
data from Table 5 of the spreadsheet indicate that the concentration gradient is
affecting the diffusion rates. The fact that the three lines are separate from one
another suggests that the number of carriers is also affecting diffusion rates. Thus,
the answer is both. (It is worthy of note that in many practical applications the
number of carriers will be vastly smaller than the number of carriers. Because of this,
changes in the number of carriers will typically have a more significant impact on the
diffusion rates in most "real world" applications).
What kinds of osmotic effects do you expect hypo-, hyper-, and iso-tonic solutions to
have on a cell? - ANSWER-Hypotonic solutions will cause water to be drawn into a
cell by osmosis, leading to lysis of the cell, isotonic solutions will cause no net
movement of water by osmosis, hypertonic solutions will cause water to be drawn
out of the cell by osmosis, leading to crenation of the cell.
Remember that penetrating solutes have no osmotic effect and that cells have an
osmolarity of 300 mOsmolar. What effect does a 300 mOsmolar solution of a
nonpenetrating solute have on a cell, and how does this differ from the effect of a
300 mOsmolar solution of a penetrating solute? - ANSWER-A solution of 300
mOsmoles of nonpenetrating solutes matches the tonicity of a cell and, therefore will
cause no net movement of water by osmosis. In contrast, a solution of 300
mOsmoles of a penetrating solute has a tonicity of zero (because penetrating solutes
have no osmotic effect). Therefore, placing a cell into a solution of 300 mOsmoles of
a penetrating solute would be the equivalent of placing the cell into distilled water.
The solution is hypotonic and would cause lysis of the cell. This effect of placing cells
into a 300 mOsmolar solution of a nonpenetrating was demonstrated with the 0.15M
sodium chloride and the 0.30 M glucose solutions. The effect of placing cells into a
300 mOsmolar solution of a penetrating solute was demonstrated with the 0.15 M
ammonium chloride solution and the 0.30 M urea solution.
List 3 methods used in today's lab to assess heart rate. - ANSWER-Palpation, PPG
and ECG.
,A difference between the palpated heart rate and the heart rate calculated by
auscultation is termed a - ANSWER-pulse deficit
Why is it important that the subject not know when the respiratory rate is being
assessed. - ANSWER-It can alter the true "normal" breathing pattern. If a subject
knows they are being measured or evaluated, they may unconsciously behave
differently and values may not be as accurate.
What is the difference between assessing blood pressure by auscultation and
assessing blood pressure by palpation? - ANSWER-Both use a sphygmomanometer
but auscultation uses a stethoscope over the brachial artery, whereby palpation
involves no stethoscope and palpation of the brachial or radial artery.
Where on the subject is the respiratory transducer placed? - ANSWER-around chest
TRUE or FALSE. When assessing blood pressure by palpation, it is very easy to
determine diastolic pressure. - ANSWER-false
Based upon your observations what are some of the advantages and disadvantages
of assessing heart rate by each of these methods under different circumstances? -
ANSWER-EKG and PPG can determine accurate heart rates and require little skill to
produce good measurements. Unfortunately, they are both unreliable if the subject is
moving.
Counting a radial pulse is accurate but requires skill on the part of the individual
doing the measurement. Because of the time required to count a pulse, changes in
heart rate that occur only briefly cannot be detected by this method.
Initially there is a high concentration of sodium on the left side of a beaker of water.
What is likely to happen (with regard to movement of ions and/or water) in this
beaker? - ANSWER-It will disperse until equilibrium is achieved and sodium is
equally distributed throughout the beaker.
What is the proper term for the process that is occurring in the beaker described
above? - ANSWER-Diffusion of a solute from a higher concentration to a lower
concentration.
A red blood cell is surrounded by a solution containing a higher concentration of
solutes than found inside of the cell. Cell membranes act a selectively permeable
membranes. What will happen to this cell? - ANSWER-The red blood cell will crenate
or shrink since it will lose water to the to the solution. Solutes will go. from a higher
concentration to a lower concentration.
What is meant by the term hypotonic solutions, and what effect would this type of
solution have on a cell? - ANSWER-There is a lower concentration of solutes (more
water) in the hypertonic solution compared to the cell. The cell would swell and lyse,
since water is going to move into it to equal concentrations on both sides.
, How is tonicity different than osmolarity? - ANSWER-Osmolarity is the concentration
of solutes in a solution. Tonicity refers to the non-penetrating solutes. In order to
determine tonicity, osmolarity is calculated.
The presence of a sloping line on a graph suggest what about the relationship
between the variable on the x-axis, and the variable on the y-axis? - ANSWER-The
sloping line between the variables on the x-axis and y-axis means the two variables
show a correlation. A positive sloping line ( / ) means there is a direct correlation,
whereby a sloping line that has a negative slope would have an indirect correlation.
Does the rate of diffusion change as the concentration gradient changes? -
ANSWER-Yes. An increase in the concentration gradient causes an increase in the
diffusion rate. The sloping line in the first graph is evidence of this relationship.
2. How do concentration gradients affect the direction of diffusion? - ANSWER-
Molecules diffuse from areas of high concentration to areas of low concentration.
Reversing the gradient will reverse the direction of the diffusions. This effect is
demonstrated in Table 2 of the spreadsheet and its graph.
Which method(s) would be the best at detecting heart rate changes that occur for
only a few seconds such as those expected as one stands? - ANSWER-The EKG or
PPG could be employed in this circumstance.
Which method(s) would be the most useful for a subject that is moving (such as
during exercise)? - ANSWER-Counting a radial pulse would be the most accurate
method in this instance because of the sensitivity of the EKG and PPG to movement.
Which is the most readily available in non-clinical settings? - ANSWER-With a watch,
a radial pulse can be counted in almost all settings.
Contrast the accuracy of these methods? - ANSWER-The relative accuracy of these
methods is somewhat context dependent. If the subject is moving, counting a radial
pulse is the most accurate alternative. However, if the patient is still the EKG and
PPG can provided more accurate measurements.
"Pulse deficit" describes a difference between pulse rate assessed by palpating a
radial pulse and heart rate assessed by auscultation (listening) or EKG. What could
account for pulse deficit? - ANSWER-Remember that the EKG is detecting electrical
activity of the heart, and auscultation is detecting the closing of the heart valves.
Neither of these directly measures the movement of the blood. Thus, if the heart is
not effective in moving blood with each beat (as could be the case with a severely
leaky valve), a pulse deficit could result.
An apparent pulse deficit may also occur if the individual making the measurement is
not skillful and, therefore, "misses" some of the pulses at the wrist.
How does blood pressure affect the plethysmography data? Does this influence
pulse rate assessment by this method? - ANSWER-Because the plethysmograph
measures the amount of blood under the skin, and increase in blood pressure would
tend to cause an increase in the amplitude of the waveform seen on the
