2019年11月IB生物SL真题下载-Paper1
1. The electron micrograph shows a thin section through a plant mesophyll cell.
What is the magnification of the image?
A. × 75
B. × 300
C. × 3000
D. × 7500
2. By which process do potassium ions move through potassium channels in axons?
A. Active transport
B. Exocytosis
C. Facilitated diffusion
D. Simple diffusion
3. Which statement provides evidence for endosymbiosis?
A. Early prokaryotes contributed to a large increase in oxygen in the atmosphere.
B. Eukaryotic mitochondria and chloroplasts have their own circular DNA.
C. Certain groups of ancient prokaryotes developed mechanisms to carry out aerobic respiration.
D. Experiments by Miller and Urey produced simple organic molecules in abiotic conditions.
4. In the micrograph, which letter points to a cell in anaphase?
5. Students examined micrographs and counted cells in the different stages of mitosis as well as those cells with no visible chromosomes. The table shows their results.
What is the mitotic index?
A. 0.2
B. 0.4
C. 0.6
D. 0.7
6. In which processes are ma]cromolecules broken down into monomers?
A. Anabolism and catabolism
B. Catabolism and hydrolysis
C. Hydrolysis and reduction
D. Reduction and anabolism
7. Which of the molecules shown would be most suitable for long-term energy storage in humans?
8. What is a property of water?
A. Water has a low specific heat capacity so large increases in heat energy cause a small temperature change.
B. Water is an excellent solvent for non-polar substances.
C. Covalent bonds between adjacent water molecules are responsible for its unique properties.
D. Water molecules are highly cohesive which is important for transport in xylem.
9. Using the nomogram, what is the minimum mass at which a woman of height 165 cm would be considered overweight?
A. 72
B. 67
C. 64
D. 61
10. What effect do changes in pH have on enzymes?
A. All enzymes increase in activity as pH increases.
B. The activity of all enzymes is reduced by a pH below or above 7.
C. Low pH causes reversible denaturation in all enzymes.
D. Extreme pH can alter the active site of all enzymes.
2019年11月IB生物SL真题余下省略！
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