Question
Topic – 3.5 Cellular Respiration
(a) – Topic – 1.1 Structure of Water and Hydrogen Bonding
(b) – Topic – 1.1 Structure of Water and Hydrogen Bonding
(c) – Topic – 3.5 Cellular Respiration
(d) – Topic – 3.5 Cellular Respiration
To investigate how increases in environmental temperatures affect the metabolism of certain organisms, researchers incubated liver cells from toads at different temperatures and measured two markers of metabolic
activity (Table 1): the rate of oxygen consumption and the rate of ATP synthesis.
(a) Describe the role of water in the hydrolysis of ATP.
TABLE 1. RATE OF OXYGEN CONSUMPTION AND ATP SYNTHESIS AT DIFFERENT TEMPERATURES
(b)
(i) Using the template in the space provided for your response, construct a bar graph that represents the data shown in Table 1. Your graph should be appropriately plotted and labeled.
(ii) Based on the data provided, determine the temperature in °C at which the rate of oxygen consumption is different from the rate of oxygen consumption at 25 C° .
(c)
(i) Based on the data in Table 1, describe the effect of temperature on the rate of ATP synthesis in liver cells from toads.
(ii) Based on the data in Table 1, calculate the average amount of oxygen consumed, in nmol, for 10 mg of mitochondrial protein after 10 minutes at 25 C° .
(d)
(i) Oligomycin is a compound that can block the channel protein function of ATP synthase. Predict the effects of using oligomycin on the proton gradient across the inner mitochondrial membrane.
(ii) Justify your prediction.
▶️Answer/Explanation
2(a) Describe the role of water in the hydrolysis of ATP.
Accept one of the following:
• Water is added in the process of cleaving/splitting (a phosphate from) ATP.
• Water breaks down/splits ATP.
2(b) Using the template in the space provided for your response, construct a bar graph that represents the data shown in Table 1. Your graph should be appropriately plotted and labeled.
Sample Responses:
Using the template in the space provided for your response, construct a bar graph that represents the data shown in Table 1. Your graph should be appropriately plotted and labeled.
• Graph is appropriately labeled.
Using the template in the space provided for your response, construct a bar graph that represents the data shown in Table 1. Your graph should be appropriately plotted and labeled.
• Data points and error bars are correctly plotted.
Based on the data provided, determine the temperature in °C at which the rate of oxygen consumption is different from the rate of oxygen consumption at 25°C.
• 30
2(c) Based on the data in Table 1, describe the effect of temperature on the rate of ATP synthesis in liver cells from toads.
Accept one of the following:
• As the temperature increases, the rate of ATP synthesis also increases.
• There is a positive relationship (between temperature and ATP synthesis).
• Temperature and ATP synthesis are directly correlated.
Based on the data in Table 1, calculate the average amount of oxygen consumed, in nmol , for 10 mg of mitochondrial protein after 10 minutes at 25°C.
1,650 [16.5 nmol/min/mg × × 10 mg 10 min ]
2(d) Oligomycin is a compound that can block the channel protein function of ATP synthase. Predict the effects of using oligomycin on the proton gradient across the inner mitochondrial membrane.
Accept one of the following:
• (The proton gradient) will increase/become steeper (and may eventually plateau).
• The difference in the concentration of protons/pH (across the inner mitochondrial membrane) will increase.
• There will be an increase in the concentration of protons/a decrease in pH in the intermembrane space relative to that found within the mitochondrial matrix. Justify your prediction.
Accept one of the following:
• (Without protons being able to flow back into the matrix through ATP synthase), more protons will accumulate in the intermembrane space/between the two mitochondrial membranes.
• (Without protons being able to flow back into the matrix through ATP synthase), there will be a lower pH in the intermembrane space/between the two mitochondrial membranes.
• Protons will not be able to flow across the membrane (through ATP synthase), but the electron transport chain will still pump protons into the intermembrane space.