Interpret temperature, pH and substrate curves using collision frequency, active-site availability and denaturation.
Tę umiejętność sprawdzają 34 zadania wzorowane na arkuszach IB z lat 2022–2026.
A model protease works best at 42 °C and pH 6.5. The experiment shown runs at 35 °C and pH 6.5. Which change can increase its rate at the plateau P? A. Reduce enzyme concentration by half B. Raise temperature from 35 °C to 42 °C C. Add more substrate while…
Discuss two variables that should be controlled in this investigation.
Explain the relationship between storage temperature and remaining enzyme activity.
Explain how temperature can affect population growth in this plant.
Animals must function under changing environmental temperatures. (a) Explain mechanisms of human thermoregulation. (b) Explain how temperature affects enzyme activity. (c) Distinguish the thermal properties of air and water in relation to animal habitats. One…
A model enzyme preparation hydrolyses a carbohydrate. The graph shows the percentage of enzyme molecules retaining activity as temperature rises. Use a simplified model in which hydrolysis becomes faster as temperature rises while nearly all molecules remain…
A continuous fungal culture produces an organic acid in a fermenter. Outline one condition needed for effective production.
A fermenter maintains a microbial culture for continuous production. Identify two conditions that should be monitored to maintain suitable growth conditions.
Enzyme concentration and temperature are constant. Why does the initial reaction rate change very little above a substrate concentration of 8 mmol L⁻¹? A. The enzyme has become a molecule of substrate B. The enzyme’s active sites are effectively saturated C.…
Suggest a reason for the effect of acid K.
Describe two other environmental factors that could affect their distribution, explaining the role of each.
Suggest a reason for the twelve-minute wait.
Outline why temperature is kept at37 degrees C.
Outline how each treatment could prevent browning: (i) applying lemon juice; (ii) covering the surface tightly with plastic film.
Suggest conclusions about how pH affects the rate of cellulose hydrolysis.
Which explanation is consistent with the labelled rate curve? Substrate is supplied in excess in each test. A. At Q, molecular kinetic energy cannot increase any further B. At S, the curve proves that all substrate has been consumed C. At R, denaturation has…
(i) Analyse the effect of grazers on species richness. (ii) Suggest reasons for an increase in richness.
A digestive enzyme is tested at different environmental conditions. Outline the effect of low temperature on its activity.
Explain how changes in pH affect the female protease preparation.
(a) Explain how temperature influences enzyme activity. (b) Outline how the thyroid gland contributes to regulation of human body temperature. (c) Describe how human activities contribute to a rise in mean surface air temperature.
A purified enzyme is tested at a fixed concentration, pH and temperature. Product is measured over very short initial intervals. Why does increasing substrate cease to raise the rate appreciably? A. The enzyme has become the main substrate B. Almost all active…
An enzyme converts substrate P to product Q. Equal enzyme and substrate concentrations are used at each pH. Which conclusion follows? A. The enzyme rate is independent of pH B. The enzyme is completely inactive at pH9 C. pH influences the measured enzyme…
A fermentation vessel is used to grow microorganisms that manufacture a useful product. Explain why conditions in the vessel must be controlled carefully.
Compare and contrast the effects of pH on the two preparations.
Outline how one harmful change caused by microbial activity could be prevented.
An enzyme preparation hydrolyses a carbohydrate substrate into smaller sugars. The enzyme concentration and temperature are held constant. Why does this model response reach a plateau? A. The enzyme active sites are occupied almost continuously B. The enzyme…
An enzyme preparation hydrolyses a carbohydrate substrate into smaller sugars. The enzyme concentration and temperature are held constant. Why does this model response reach a plateau? A. The enzyme active sites are occupied almost continuously B. The enzyme…
A model culture tests four antibacterial preparations on a bacterial lawn. X is a control disc. The plate is incubated at25°C for36hours before the schematic result is recorded. (i) Analyse the effects of the four preparations. (ii) Outline one reason for…
Explain the large nutrient transfer from litter to soil.
Deduce how each compound would affect stomach pH.
Explain how hydrochloric acid contributes to protein digestion in the stomach.
An enzyme is assayed at constant pH and substrate concentration. Explain why activity is lower on either side of the optimum temperature.
The enzyme was assayed for the same duration at each temperature with fresh substrate and a fixed initial enzyme concentration. What best explains the decrease above 42°C? A. The substrate must become chemically identical to the enzyme B. Molecular collisions…
Three microbial amylases are compared using equal enzyme concentrations at the same temperature. Which conclusion follows from these constructed results? A. Q has the highest optimum pH B. P has its highest measured rate at pH 7 C. R is inactive at every…
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