Theme C: Interaction and interdependence

19 original questions · 19 derived marking activities. Teaching explanations are AI-authored; independent teacher review is pending.

19 of 38 activities match

• Question 1Explain how enzymes lower the activation energy of a reaction, using the concept of the enzyme-substrate complex.AI checkedStandard3 marksNo calculator+
• Question 3Explain the effect of increasing temperature above the optimum on the rate of an enzyme-catalysed reaction.AI checkedStandard3 marksNo calculator+
• Question 5Extension practice (includes HL content beyond the prescribed SL syllabus): Outline the difference between anaerobic cell respiration in yeast (alcoholic fermentation) and in human muscle cells (lactic acid fermentation).AI checkedEnrichmentStandard3 marksNo calculator+
• Question 7Extension practice (includes HL content beyond the prescribed SL syllabus): Compare the net ATP yield per glucose molecule of fermentation in yeast or human muscle with aerobic cell respiration, and explain the reason for the difference.AI checkedEnrichmentStandard3 marksNo calculator+
• Question 9Annual net production is 48 000 kJ $m^{-2}$ yr^-1 for producers and 7200 kJ $m^{-2}$ yr^-1 for primary consumers. Calculate the percentage energy transfer and explain three causes of energy loss between these trophic levels.AI checkedStandard5 marksCalculator+
• Question 11Distinguish between a population, a community and an ecosystem.AI checkedFoundation3 marksNo calculator+
• Question 13Explain the role of decomposers in recycling nutrients within an ecosystem.AI checkedStandard3 marksNo calculator+
• Question 15Outline the processes by which carbon enters and leaves the atmosphere as part of the carbon cycle.AI checkedStandard4 marksNo calculator+
• Question 17A food chain is: grass → grasshopper → frog → snake. Identify the trophic level of the frog and explain why food chains rarely extend beyond four or five trophic levels.AI checkedStandard3 marksNo calculator+
• Question 19Outline how a pyramid of energy differs from a pyramid of numbers, and state one advantage of using a pyramid of energy.AI checkedStandard2 marksNo calculator+
• Question 21Explain how competition for a limited resource can affect the carrying capacity of a population in an ecosystem.AI checkedStandard3 marksNo calculator+
• Question 23Extension practice (HL content beyond the prescribed SL syllabus): Outline the process of primary succession, from bare rock to a more established community.AI checkedEnrichmentStandard3 marksNo calculator+
• Question 25Outline one method that estimates animal population size from directly sampled individuals and one method that uses indirect signs to estimate relative abundance in the field.AI checkedStandard2 marksNo calculator+
• Question 27Outline the process by which nerve impulses are transmitted across a chemical synapse.AI checkedStandard4 marksNo calculator+
• Question 29Outline how the antibody-mediated (humoral) immune response leads to the production of antibodies against a specific pathogen.AI checkedStandard4 marksNo calculator+
• Question 31A food chain transfers energy from producers storing 10,000 kJ $m^{-2}$ year^-1. Assuming 10% is transferred at each step, calculate the energy available to (a) primary consumers, (b) secondary consumers and (c) tertiary consumers. Explain how the decline in available energy limits food-chain length.AI checkedStandard4 marksCalculator+
• Question 33A population of deer introduced to an island shows exponential growth initially, but the growth rate slows and eventually levels off as the population approaches the island's carrying capacity. Explain two factors that could limit further population growth as the population nears carrying capacity.AI checkedStandard3 marksNo calculator+
• Question 35Explain how carbon moves from the atmosphere into living organisms, and then back into the atmosphere, as part of the carbon cycle.AI checkedStandard3 marksNo calculator+
• Question 37A student counts a moss species in five equal quadrats beneath trees and five equal quadrats in an open area. Counts beneath trees are 12, 9, 15, 10 and 14; open-area counts are 3, 5, 4, 2 and 6. (a) Calculate the mean count for each habitat. (b) State the pattern shown. (c) Identify one limitation of the investigation. (d) Suggest one improvement that directly addresses that limitation.AI checkedStandard4 marksNo calculator+