Biology for IGCSE & O level - Plant Nutrition (Section 6)
1
How does increasing light intensity affect the rate of photosynthesis?
Answer
(B)
The rate increases until it reaches a plateau.
2
What happens to the stomata when a leaf is in hot and dry conditions?
Answer
(B)
They close to prevent water loss.
3
How does increasing the light intensity affect the rate of photosynthesis if the CO2 concentration and temperature are held constant?
Answer
(C)
The rate increases up to a certain point and then levels off.
4
What is the primary product of photosynthesis that provides energy for the plant?
Answer
(C)
Glucose
5
Which part of a leaf is responsible for transporting sugars from the leaf to other parts of the plant?
Answer
(B)
Phloem
6
What is the function of the spongy mesophyll layer?
Answer
B
C
7
What is the role of the spongy mesophyll in the process of gas exchange?
Answer
B
D
8
Which molecule provides the electrons needed to replace those lost by chlorophyll during photosynthesis?
Answer
(C)
Water
9
What are the key outputs of the light-dependent reactions?
Answer
(B)
ATP and NADPH
10
Which of the following is NOT a factor that affects the rate of photosynthesis?
Answer
(C)
Soil type
11
What are the main products of the light-dependent reactions used in the light-independent reactions?
Answer
B
C
12
How does the distance of a light source affect the rate of photosynthesis?
Answer
(B)
The closer the source, the higher the rate
13
Which of the following components are directly involved in the light-dependent reactions of photosynthesis?
Answer
A
B
14
If a plant is in an environment with very low light intensity, which of the following factors would most likely be the limiting factor for photosynthesis?
Answer
(C)
Light intensity
15
What is the role of enzymes in photosynthesis?
Answer
(A)
They act as a catalyst for photosynthesis reactions.
16
What is the role of water in photosynthesis?
Answer
(B)
It is a reactant in the process, providing electrons and hydrogen ions.
17
Which of the following factors are involved in the light independent reactions of photosynthesis?
Answer
A
C
D
18
What is the function of guard cells in a leaf?
Answer
(C)
To regulate the opening and closing of stomata
19
During the starch test experiment, what is the purpose of removing the chlorophyll from the leaf using hot ethanol?
Answer
(B)
To make the leaf more transparent to see starch
20
What are the reactants that a plant takes up to perform photosynthesis?
Answer
A
C
D
21
Which factor(s) directly influence the rate of photosynthesis?
Answer
A
B
C
22
What essential mineral is directly involved in the formation of chlorophyll?
Answer
(D)
Magnesium
23
Why does a leaf have a large surface area?
Answer
(B)
To absorb light rays
24
What is the main function of the stomata in leaves?
Answer
(C)
To exchange gases (carbon dioxide and oxygen)
25
What is the effect on a plant if it has a lack of a mineral ion?
Answer
(C)
The plant may develop deficiency symptoms.
26
What does a leaf turn blue-black after iodine is applied to it?
Answer
(B)
Indicates the presence of starch.
27
In the starch test, what is the role of ethanol?
Answer
(B)
To remove chlorophyll
28
What type of tissue in a leaf has large air spaces, promoting gas exchange?
Answer
(C)
Spongy mesophyll
29
How do the light-dependent and light-independent reactions work together in photosynthesis?
Answer
(B)
Light-dependent reactions produce ATP and NADPH, which are used in the light-independent reactions.
30
What does the thin shape of a leaf allow for?
Answer
(B)
Easier diffusion of gases
31
In photosynthesis, light energy is used to split water molecules. What are the immediate products of this process?
Answer
B
C
D
32
During which part of the day is most photosynthesis happening?
Answer
(C)
Daylight
33
What is the function of the thylakoids within the chloroplast?
Answer
(C)
To contain chlorophyll and carry out the light-dependent reactions.
34
Which of the following best describes the role of the stomata?
Answer
(B)
To allow gas exchange between the leaf and the atmosphere.
35
What is the role of RuBisCO in photosynthesis?
Answer
(C)
To fix carbon dioxide.
36
What is the function of the guard cells?
Answer
A
C
37
How does carbon dioxide concentration influence the rate of photosynthesis?
Answer
(C)
Increasing CO2 speeds up the rate up to a point, then it plateaus
38
What is the role of the enzyme RuBisCO?
Answer
(C)
To fix carbon dioxide in the Calvin cycle
39
What type of energy is ultimately stored in the glucose produced during photosynthesis?
Answer
(C)
Chemical energy
40
What are the main differences between plant and animal cells that are vital for photosynthesis?
Answer
A
B
D
41
Why do plants that grow in tropical regions often have higher rates of photosynthesis compared to plants in colder regions?
Answer
(B)
Tropical regions have higher light intensity and optimal temperatures for photosynthesis.
42
What is the purpose of the waxy cuticle on the leaf surface?
Answer
(C)
To reduce water loss.
43
What is the balanced symbol equation for photosynthesis?
Answer
(A)
CO2 + H2O -> C6H12O6 + O2
44
What are the main components needed for photosynthesis to occur?
Answer
A
B
C
45
What is the primary function of the light-dependent reactions?
Answer
B
D
46
Which factor(s) will limit the rate of photosynthesis if it's very hot and dry?
Answer
B
D
47
Which of the following is an example of a product of photosynthesis?
Answer
A
B
48
What would be the expected appearance of a plant suffering from magnesium deficiency?
Answer
(A)
Yellowing of the leaves
49
What would happen if a plant did not have the mineral ions that it needs?
Answer
(B)
It would develop deficiency symptoms.
50
Which of the following is NOT a product of photosynthesis?
