1. What is the word equation of photosynthesis?
Carbon dioxide + water à carbohydrates + oxygen
2. What are the raw material(s), product(s) and by product(s) of photosynthesis?
Material: carbon dioxide and water
Product: carbohydrates
Byproduct: oxygen
3. On the whole, what is the actual process of photosynthesis?
- The process of light energy being converted to chemical energy.
- The process of the conversion of simple inorganic substances into complex organic substances(chemical energy is stored in these organic substances).
4. In photosynthesis, what is the role of chloroplast?
Chloroplast is the place where photosynthesis is carried out.
5. What are the functions of chlorophyll, thylakoid and stroma separately?
Chlorophyll is responsible for absorbing light.
The membrane of thylakoid contains chlorophyll and different kinds of enzymes that catalyze the reactions in the light reaction.
The stroma contains different kinds of enzymes that catalyze the reactions involved in the dark reaction.
6. What structures are there in terrestrial leaf? (Name at least 13)
Upper epidermis, cuticle
Mesophyll, palisade mesophyll (consist of palisade mesophyll cells), spongy mesophyll (consist of spongy mesophyll cells), air space, chloroplast
Vascular bundles, xylem, phloem,
Lower epidermis, stomata, guard cell
7. What are the strategies that terrestrial plants used to adapt to photosynthesis?
(1) to absorb the greatest amount of light
(2) to absorb the greatest amount of carbon dioxide
(3) to absorb the greatest amount of water
(4) to be able to immediately transport away products and by products
8. What are the features of the internal structures of terrestrial leaves that enable them to absorb the most amount of light?
(1) The upper epidermis is transparent. (such that light can pass through and reach the chloroplast containing tissue)
(2) The palisade mesophyll cells are closely packed. (so as to maximize the density of chloroplasts)
(3) Palisade mesophyll cells contains large amount of chloroplast. (so as to maximize the absorption of light)
(4) The spongy mesophyll cells contains chloroplast. (so as to capture the remaining light that is not absorbed by palisade mesophyll cells)
(5) The lower epidermis is transparent (though some plant are not), so the remaining unabsorbed light can pass through and for leaves in the lower layers to absorb.
9. What are the features of the internal structures of terrestrial leaves that enable them to absorb the most amount of carbon dioxide?
(1) there are stomata in the upper and lower epidermis (because there are cuticle in both epidermis, therefore there is a need for stomata)
(2) the lower epidermis has a higher density of stomata. (to prevent water loss by evaporation)
(3) the spongy mesophyll is loosely arranged. (so as to allow carbon dioxide to reach the palisade mesophyll cells more easily)
10. In order to reduce water loss or retain water, what features do terrestrial leaves usually have?
(1) thick cuticle (shiny surface)
(2) less stomata
(3) sunken stomata
(4) thick leaf
(5) reduce the number of leaf or needle leaf
11. What is the difference between the leaves of submerged plants and terrestrial plants?
(1) There are no cuticle in both epidermis
(2) There are no stomata
(3) The cells inside the should be loosely packed for contain air so as to provide buoyancy.
12. In water, how does plants absorb carbon dioxide?
Directly absorb carbon dioxide from the epidermis.
13. What are the internal structures of terrestrial leaves that are adapted for transporting a sufficient amount of water?
They have leaf veins. Leaf veins contain xylem. Leaf veins are dispersed throughout the leaf.
14. Apart from internal structures, what are the features of the leaf as a whole that are adapted to photosynthesis?
(1) the leaf is broad and flat. (can provide large surface area)
(2) the leaf is thin. (so as to allow carbon dioxide and light to easily reach photosynthetic cells.)
(3) the leaves are arranged in a mosaic pattern. (such that the leaf in the upper layer will not block the leaves in the lower layer)
(4) The stems of plants are positively phototropic.
15. What structures does chloroplast have?
Double membrane, thylakoid, grana, stroma, starch granule, DNA
16. What features do chloroplast have to adapt to carrying out photosynthesis?
(1) The stroma is in liquid state where enzymes that catalyze photosynthesis are found.
(2) The thylakoid membrane contains chlorophyll and other pigments that can absorb light.
(3) The thylakoid are in large number and are arranged in stacks called grana (singular-granum).
(4) There are connections between grana.
17. According to the process of photosynthesis, what are the parameters that can be used to check/test whether photosynthesis is being carried out or not?
(1) The reduction rate of raw material, that is the consumption rate of carbon dioxide and water.
(2) The production rate of products. That is the formation rate of carbohydrates and oxygen.
(3) The rate of absorption of light/
Note: In secondary school, usually the rate of formation of starch or oxygen is checked.
18. What is the principle behind using the production of starch to check/test whether photosynthesis has taken place or not? What process must be first carried out?
The glucose formed from photosynthesis will quickly combined to become starch, and the starch will be stored in the leaf.
The process ‘Destarching’ must first be carried out.
19. What is the principle behind ‘destarching’?
To put the leaf in dark for a period of time so that the leaf will not carry out photosynthesis and produce starch.
Since the leaf still have to use food to carry out respiration, the starch stored in the leaf will slowly turn into glucose for respiration to be carried out.
20. How can the amount of starch in a leaf be tested?
(1) Put the leaf into boiling water. (so that enzyme will get denature and lose their activity)
(2) Put the leaf into alcohol. (alcohol can damage the cell membrane so that
the chlorophyll can be released, so that the leaf will lose the green colour and become whiter for easy observation)
(3) then put the leaf into hot water (to soften the leaf because alcohol drive away water and make the leaf hard and brittle)
(4) Add iodine to the leaf. (If blue black colour comes up, there is starch; if the colour is brown, no starch.)
21. To test whether photosynthesis require chlorophyll, a special kind of leaf is need, why?
Variegated leaf. (i.e. there are at least two different colour on the leaf)
22. What are the chemicals that can be used to absorb carbon dioxide?
Potassium hydroxide KOH
Sodium hydroxide NaOH
23. Why should experiments of photosynthesis usually require the ‘destarching’ process?
The ‘destaching process is required to ensure that the starch detected after the experiment is produced during the experiment.
Note: Do not only write ‘to make the experiment result more accurate’.
24. What are the three process of light reaction?
(1) absorb light
(2) formation of ATP (photophosphorylation)
(3) Photolysis of water (water split into hydrogen and oxygen)
25. What are the product of light reaction?
(1) ATP (transferred to dark reaction)
(2) NADPH (transferred to dark reaction)
(3) oxygen (leave the chloroplast)
26. What are the uses of ATP and NADPH produced in the light reaction?
They are used to fix the carbon (carbon dioxide) into organic compounds.
The process is a type of carbon fixation. It happens in the stroma. Light is not required. Therefore it is called ‘dark reaction’, and also called ‘Calvin cycle’.
27. What are the three major chemical in Calvin cycle?
(1) 3C compound
(2) triose phosphate (3C) (glucose is converted from this chemical)
(3) 5C compound
28. What are the three processes in Calvin cycle?
(1) The fixation of carbon dioxide and the formation of 3C compound,
(2) The reduction of 3C compound and the formation of glucose,
- i.e. 3C compound becoming triose phosphate, this is a reduction reaction requiring ATP and NADPH.
(3) The regeneration of carbon dioxide acceptor (i.e. 5C compound)
- require ATP
29. List all the factors that affect the rate of photosynthesis.
(1) light intensity
(2) Carbon dioxide concentration
(3) temperature
30. What is limiting factor?
If certain factor is increasing, and the rate photosynthesis increases as a result, then this factor is called the ‘limiting factor’.
Note: Since different factors in different stages can be the ‘limiting factor’, therefore we will not say certain factor (e.g. light) is always the limiting factor. We will only, according to different situation, judge whether the factor is a limiting factor or not.
31. What is the primary product of photosynthesis?
Triose phosphate
32. What is the fate of the product of photosynthesis?
In short, they are used in the formation of other organic maters in the organism, including
(1) other carbohydrates (e.g. starch)
(2) lipids
(3) protein
(4) vitamins
33. What is the importance of photosynthesis?
(1) to produce original food source for the ecosystem (including for animal and for the plant itself)
(2) maintain a continuous energy flow within the ecosystem.
(3) Maintain the balance of oxygen and carbon dioxide within the atmosphere. (provide oxygen for living organism for breathing)
34. What assumption has to be made when the rate of production of bubble is used to measure the rate of photosynthesis?
(1) The size of the bubbles are the same.
(2) The rate of oxygen dissolving into water do not change.
35. What is the fate of ADP and NADP that is formed from Calvin cycle?
They will be used again in the light reaction.