HL 2 December 2024 Past Paper PDF

Study Guide for SL/HL 2 December 2024 This is a guide to help you prepare for the exam. Please Study and review your past worksheets and notes. 1. Which ecological level involves biotic factors but not abiotic factors? a. Community b. Ecosystem c....

Study Guide for SL/HL 2 December 2024 This is a guide to help you prepare for the exam. Please Study and review your past worksheets and notes. 1. Which ecological level involves biotic factors but not abiotic factors? a. Community b. Ecosystem c. Population d. Both A and C 2. What best defines the concept of carrying capacity? a. The number of species an environment can support b. The minimum population a species can maintain c. The maximum population a species can sustain d. The total individual count of all species in an area 3. Which example shows negative feedback in regulating population size? a. Predators bringing prey population back to carrying capacity b. An increase in prey leading to fewer predators c. Changes in environmental factors that do not depend on population density d. Exponential population growth 4. What defines an alien species? a. A species introduced to an area by human action b. A species with widespread geographical distribution c. A species not yet discovered by scientists d. A harmful or pathogenic species 5. How would an ecologist use a quadrant in their research? a. Estimate animal immigration and emigration b. Measure plant population sizes by sampling c. Trap and mark animals for release d. Measure light intensity based on the Sun's position 6. What statistical test would help determine if two species of limpets occur together by chance or due to interaction?  a. Chi-squared test b. T-test c. Standard deviation d. Means and ranges Cellular Respiration and Metabolism 7. Which products are common to both anaerobic and aerobic respiration in humans? a. Pyruvate b. ATP c. Lactate d. Pyruvate and ATP 8. What is the net ATP yield from glycolysis for each molecule of glucose? a. 2 b. 4 c. 10 d. 38 9. In the mitochondria, how do protons flow during ATP synthesis? a. From the matrix to the intermembrane space b. From the intermembrane space to the matrix c. From the intermembrane space to the cytoplasm d. From the cytoplasm to the intermembrane space 10. What occurs during the link reaction in aerobic respiration? a. NAD+ is reduced b. Pyruvate undergoes decarboxylation c. It occurs in the cytoplasm d.. FAD+ is reduced 11. What happens during glycolysis when a hexose sugar is broken down? a. Phosphorylation → oxidation → lysis b. Oxidative → phosphorylation → lysis  c. Phosphorylation → lysis → oxidation d. Lysis → oxidation → phosphorylation 12. Which process directly generates ATP in mitochondria? a. Proton movement from the matrix to the intermembrane space b. Proton movement from the intermembrane space to the matrix c. Splitting of water and electron transfer to oxygen d. Proton movement from the intermembrane space to the cytoplasm Enzymes and Biochemical Reactions 13. How do enzymes influence activation energy? a. Lower the energy required for reaction initiation b. Increase the energy required for the reaction c. Alter the shape of the active site d. Stabilize the reaction pathway 14. What is the effect of a competitive inhibitor on enzyme activity? a. Decreases reaction temperature b. Increases substrate concentration c. Enhances the activity of the enzyme d. Increases the temperature at which the reaction occurs 15. Which describes the induced-fit model of enzyme binding? a. The substrate and active site are complementary in shape b. Both the enzyme and substrate undergo conformational changes c. Enzymes bind to a specific substrate d. Enzymes can be immobilized 16. What happens in feedback inhibition? a. Changes in transpeptidases lead to antibiotic resistance b. The pathway that produces isoleucine is regulated c. The use of statins to control cholesterol is an example d. The Calvin cycle is regulated Photosynthesis and Plant Biology 17. Where is chlorophyll located within plant cells? a. Thylakoid membranes b. Stroma c. Mitochondrial matrix d. Cristae 18. What is produced by the light-dependent reactions of photosynthesis that is later used in the Calvin cycle? a. Hydrogen and oxygen b. ATP and NADPH c. NADPH and oxygen d. ATP and CO2 19. What occurs in the light-independent reactions of photosynthesis? a. Water molecules are split b. ATP is synthesized c. NADP is reduced d. CO2 is reduced 20. Which molecule is the first identifiable product after carbon fixation in photosynthesis? a. Ribulose bisphosphate (RuBP) b. Glycerate-3-phosphate (GP) c. Triose phosphate (TP) d. Acetyl CoA 21. What is the function of thylakoid membranes in the chloroplasts? a. They create a high concentration of protons for ATP production b. They concentrate photosynthetic pigments c. They provide a surface for the Calvin cycle enzymes d. They produce ATP and NADPH Nerve Function and Action Potentials 22. Which ion movement triggers an action potential in a neuron? a. Calcium b. Magnesium c. Sodium d. Potassium 23. What happens after the highest point of the action potential in a nerve impulse? a. Sodium channels open, and Na+ enters the neuron b. Sodium channels open, and Na+ exits the neuron c. Potassium channels open, and K+ exits the neuron d. Potassium channels open, and K+ enters the neuron 24. During synaptic transmission, what happens to calcium ions? a. They enter the synaptic knob from the synaptic cleft b. They enter the postsynaptic neuron from the cleft c. They leave the synaptic knob into the synaptic cleft d. They leave the postsynaptic neuron into the synaptic cleft 25. What restores the resting potential of a neuron after depolarization? a. Sodium ions diffuse out of the neuron b. Potassium ions diffuse into the neuron c. Potassium ions diffuse out of the neuron d. Sodium ions diffuse into the neuron Immunology and Hormonal Control 26. Which cells are primarily responsible for secondary immune responses? a. Cytotoxic T-cells b. Phagocytes c. Memory cells d. Macrophages 27. Which of the following describes the role of oxytocin?  a. Stimulates uterine contractions b. Controls fetal brain development c. Initiates ovulation d. Supports blastocyst implantation 28. What causes glucagon secretion to increase?* a. Fasting for a long period b. After a carbohydrate-rich meal c. During physical rest d. When body temperature drops 29. Which cells are responsible for destroying virus-infected body cells? a. Activated B-cells b. Cytotoxic T-cells c. Plasma cells formed by clonal selection d. Phagocytic macrophages 30. Which part of the immune system helps fight bacterial infections? a. Antigen presentation by macrophages b. Activation of helper T-cells c. Activation of B-cells d. All of the above in sequence