Phloem Loading
Hardbiology
Active phloem loading of sucrose into sieve elements raises osmotic pressure causing:
Select the correct option:
Solution
Incorrect! Answer:
Turgor increase driving mass flow
- Munch's Mass Flow Hypothesis: Explains how sugars are transported in phloem from 'source' to 'sink'.
- Phloem Loading: Sugars are actively loaded into the sieve tube elements at the source (leaves).
- Osmosis: This high concentration of sugar lowers the water potential in the sieve tube, causing water to diffuse in from the adjacent xylem by osmosis.
- Pressure Build-up: The entry of water increases the hydrostatic pressure (turgor pressure) in the phloem.
- Bulk Flow: This high-pressure area 'pushes' the sap toward the low-pressure 'sink' (roots/fruits), where sugars are unloaded.
🔒 Solution Hidden from View
Submit your answer to unlock the detailed step-by-step solution.
About This Question
- Subject
- biology
- Chapter
- plant physiology
- Topic
- phloem loading
- Difficulty
- Hard
- Year
- 2025
Solution
Correct Answer:
Turgor increase driving mass flow
- Munch's Mass Flow Hypothesis: Explains how sugars are transported in phloem from 'source' to 'sink'.
- Phloem Loading: Sugars are actively loaded into the sieve tube elements at the source (leaves).
- Osmosis: This high concentration of sugar lowers the water potential in the sieve tube, causing water to diffuse in from the adjacent xylem by osmosis.
- Pressure Build-up: The entry of water increases the hydrostatic pressure (turgor pressure) in the phloem.
- Bulk Flow: This high-pressure area 'pushes' the sap toward the low-pressure 'sink' (roots/fruits), where sugars are unloaded.
This hard difficulty biology question is from the chapter plant physiology, covering the topic of phloem loading. It appeared in the 2025 exam.
Looking for more practice? Explore all biology questions or browse plant physiology questions on RankGuru.