Online Test — Transport in Plants
15 Questions • 15 min • Chapter MCQ
15:00
Question 1 of 15
Movement of molecules from higher to lower concentration without energy is:
Active transport
Diffusion
Translocation
Transpiration
Explanation: Diffusion is passive movement down a concentration gradient.
Question 2 of 15
Osmosis is the movement of water across a:
Thick wall
Semi-permeable membrane
Xylem vessel only
Stoma
Explanation: Osmosis occurs across a semi-permeable membrane.
Question 3 of 15
Pure water has a water potential of:
Highly negative
Zero (the highest)
Always positive and large
Undefined
Explanation: Pure water has the highest water potential, taken as zero.
Question 4 of 15
A plant cell in a hypertonic solution undergoes:
Turgidity
Plasmolysis
No change
Cell division
Explanation: Water leaves the cell, causing it to shrink (plasmolysis).
Question 5 of 15
Transport that uses ATP to move substances against the gradient is:
Diffusion
Osmosis
Active transport
Facilitated diffusion
Explanation: Active transport uses energy to move against the gradient.
Question 6 of 15
Water and minerals are mainly absorbed by:
Leaves
Root hairs
Stomata
Flowers
Explanation: Root hairs absorb most water and minerals.
Question 7 of 15
Water rises from roots to leaves through the:
Phloem
Xylem
Cortex
Epidermis
Explanation: The xylem carries water upward (ascent of sap).
Question 8 of 15
The main force for the ascent of sap in tall trees is:
Root pressure alone
Transpiration pull
Gravity
Wind
Explanation: Transpiration pull (cohesion–tension) drives the ascent of sap.
Question 9 of 15
Most transpiration takes place through the:
Lenticels
Stomata
Roots
Bark
Explanation: Stomata in leaves are the main site of transpiration.
Question 10 of 15
Stomatal opening and closing is controlled by:
Guard cells
Root hairs
Xylem vessels
Sieve tubes
Explanation: Turgid guard cells open the stoma; flaccid ones close it.
Question 11 of 15
Besides water loss, transpiration also:
Stops photosynthesis
Cools the plant
Blocks the xylem
Makes food
Explanation: Transpiration cools the plant and aids transport of water and minerals.
Question 12 of 15
Transport of food in plants is called:
Transpiration
Translocation
Osmosis
Diffusion
Explanation: Translocation is the transport of food through the phloem.
Question 13 of 15
Food is translocated mainly as:
Glucose
Sucrose
Starch
Cellulose
Explanation: Sucrose is the main form in which food is transported.
Question 14 of 15
Unlike the xylem, the phloem can transport food:
Only upward
Only downward
In any direction (source to sink)
Not at all
Explanation: Phloem moves food in any direction, from source to sink.
Question 15 of 15
The accepted mechanism of phloem transport is the:
Cohesion–tension theory
Pressure-flow hypothesis
Lock-and-key model
Five-kingdom system
Explanation: The pressure-flow (mass-flow) hypothesis explains phloem transport.