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Biology for IGCSE & O level - Transport In Plants (Section 5)

1
Why are aphid stylets used in studies of phloem transport?
Answer
(B)
To collect phloem sap for analysis.
2
What is the main function of sieve tube elements?
Answer
(B)
Transporting sugars
3
How is water transported in plants?
Answer
(B)
Through osmosis and transpiration pull
4
What are the major components transported in the phloem?
Answer
(B)
Sugars and amino acids
5
Which of the following is the best definition of water potential?
Answer
(A)
The potential energy of water per unit volume, relative to pure water.
6
What is the role of root hairs in the uptake of water?
Answer
(B)
To increase the surface area for water absorption.
7
What is the role of companion cells in the phloem?
Answer
(B)
They provide metabolic support to sieve tube elements.
8
What are the components of a vascular bundle?
Answer
A
B
C
9
What is the role of the xylem in a plant?
Answer
(B)
To transport water and minerals.
10
How does the process of transpiration affect a plant's temperature?
Answer
(B)
It decreases the plant's temperature.
11
In which direction does translocation typically occur?
Answer
(C)
From source to sink
12
How does the presence of lignin contribute to the function of xylem?
Answer
(B)
It provides strength and support to the xylem vessels.
13
What is the primary function of the stomata in a plant?
Answer
(C)
Regulating gas exchange and water loss
14
What is the function of companion cells?
Answer
(B)
To provide metabolic support to the sieve tube elements.
15
What is the role of guard cells?
Answer
(C)
To open and close stomata.
16
Which of the following is a key characteristic of sieve tube elements?
Answer
(B)
They have perforated end walls (sieve plates).
17
What is the process that causes water to move from the soil to the xylem?
Answer
(B)
Osmosis
18
What is meant by the term 'transpiration pull'?
Answer
(B)
The force that draws water up the xylem.
19
What are the two main tissues involved in transport in vascular plants?
Answer
(B)
Xylem and phloem
20
Where are sugars synthesized in a plant?
Answer
(C)
Leaves
21
What is the name of the process by which water moves from the soil into the roots?
Answer
(B)
Osmosis
22
Which of the following is primarily involved in long-distance transport in a plant?
Answer
A
B
23
What is the role of cohesion and adhesion in the transpiration stream?
Answer
A
B
24
What is the main factor that determines the direction in which water moves across a plant's root hairs?
Answer
(B)
Water potential gradient
25
Which of the following statements is true regarding the effects of temperature on transpiration?
Answer
(B)
Increased temperature increases transpiration rate.
26
What are the main components of xylem?
Answer
(B)
Vessel elements and tracheids
27
What is the role of the companion cells in the phloem?
Answer
(B)
To provide metabolic support to sieve tube elements.
28
What is the main function of the Casparian strip?
Answer
(B)
To control which substances enter the xylem.
29
How are sugars translocated in phloem?
Answer
(C)
By mass flow (pressure flow).
30
What are the characteristics of xylem vessels which helps in their functions?
Answer
A
B
D
31
What is the role of turgor pressure in plant cells?
Answer
(B)
To maintain cell rigidity.
32
Which of the following best explains the movement of water through the root, from the soil to the xylem?
Answer
(B)
Water enters the root hairs by osmosis, then travels through the cortex to the xylem.
33
What is the role of stomata?
Answer
(C)
To regulate gas exchange and water loss.
34
What is the name of the process by which water evaporates from the leaves of a plant?
Answer
(B)
Transpiration
35
Which of the following factors would likely decrease the rate of transpiration?
Answer
(C)
Reduced light intensity
36
Which of the following statements accurately describes the direction of translocation?
Answer
(C)
From source to sink.
37
Where does transpiration primarily occur in a plant?
Answer
(C)
The leaves
38
What is the role of the casparian strip in the endodermis of the root?
Answer
(B)
To regulate water movement into the xylem.
39
What is the role of the guard cells in a leaf?
Answer
(C)
To open and close the stomata.
40
How does the light affect the rate of transpiration?
Answer
(A)
Higher light intensity increases transpiration.
41
What is the term for the movement of sugars through the phloem?
Answer
(B)
Translocation
42
What is the role of companion cells in phloem transport?
Answer
(B)
They provide metabolic support to sieve tube elements.
43
What is the process called by which water vapor escapes through stomata?
Answer
(D)
Transpiration
44
Which tissue is primarily responsible for providing support and mechanical strength to a plant?
Answer
(B)
Xylem
45
How does a plant regulate the opening and closing of stomata?
Answer
(B)
By the turgor pressure of the guard cells.
46
Which of the following is NOT a factor affecting the rate of transpiration?
Answer
(D)
Soil pH
47
Which of the following conditions would likely cause stomata to close?
Answer
A
C
48
What type of transport is involved in moving mineral ions from the soil into the root hairs?
Answer
(C)
Active transport
49
What is the role of cohesion in water transport?
Answer
(B)
To help water molecules stick to each other.
50
What conditions lead to wilting of a plant?
Answer
(C)
The loss of water from the plant exceeds water uptake.