IB DP Biology- C1.3 Photosynthesis IB Style Questions For HL Paper 1A-FA 2025
▶️ Answer/Explanation
Substance Z has an \( R_f \) of 0.5, which matches closely with chlorophyll b (\( R_f = 0.45 \)). The pigment X, located higher on the chromatogram, has an \( R_f \) of about 0.65 and matches chlorophyll a. Pigment Y, near the top, corresponds to a pigment with an \( R_f \) higher than 0.8, likely chlorophyll a’s neighbor in mobility.
✅ Answer: (D)
✅ Answer: (D)
▶️ Answer/Explanation
The labeled parts of the chloroplast are:
| Label | Structure | Description |
|---|---|---|
| A | Outer membrane | The smooth, protective outer boundary that regulates molecular movement in and out of the chloroplast. |
| B | Stroma | The fluid-filled region surrounding the thylakoids where the Calvin cycle (light-independent reactions) occurs. |
| C | Granum | A stack of thylakoids where light-dependent reactions take place. |
| D | Thylakoid membrane | The membrane system that contains chlorophyll; site of ATP and NADPH formation during photosynthesis. |
✅ Answer: (B) — The Calvin cycle occurs in the stroma.