The document describes several experiments to test the essential conditions and limiting factors of photosynthesis: 1. Tests are described to determine the necessity of starch, sunlight, chlorophyll, and carbon dioxide for photosynthesis using iodine solutions and destarching plants. 2. Experiments vary light intensities, temperatures, and carbon dioxide concentrations to determine their effects on the rate of photosynthesis. 3. The set up involves placing a cut plant in a tube with sodium hydrogen carbonate solution and altering the conditions to observe their impacts.

1. T E S T F O R S T A R C H
T E S T F O R N E C E S S I T Y O F S U N L I G H T
P U T L E A F I N B O I L I N G W A T E R A N D A F T E R W A R D S I N T O A T U B E C O N T A I N I N G
S O M E A L C O H O L O R E T H A N O L A N D P L A C E T U B E I N A B E A K E R O F H O T W A T E R
T A K E B R I T T L E L E A F A N D P L A C E I T I N H O T W A T E R T O M A K E I T M O R E
P E R M E A B L E T O I O D I N E S O L U T I O N
R E M O V E T H E L E A F A N D A D D F E W D R O P S O F I O D I N E O N I T
D E S T A R C H A P L A N T B Y P U T T I N G I T I N T H E D A R K
P L A C E T H E P L A N T I N S T R O N G S U N L I G H T W I T H S O M E P A R T S O F L E A F
C O V E R E D W I T H A B L A C K P A P E R
U N C O V E R E D P A R T S W I L L T U R N B L U E B L A C K W H E N M I X E D W I T H I O D I N E
I N D I C A T I N G P R E S E N C E O F S T A R C H
Destarch : remove stored food // stop
process of photosynthesis
Placing leaves in boiling water stops enzyme
reactions as they get denatured
Placing leaves in alcohol removes chlrophyll (
green pigment) so leaves will turn whitish

2. T E S T F O R N E C E S S I T Y O F C H L O R O P H Y L L
T E S T F O R N E C E S S I T Y O F C A R B O N D I O X I D E
D E S T A R C H A P L A N T T H E N E X P O S E I T T O S T R O N G S U N L I G H T
T A K E O N E L E A F A N D S E E T H E D I S T R I B U T I O N O F G R E E N ( C H L R O P H YL L )
D E C O L O U R I S E I T A N D T E S T I T F O R S T A R C H
S E E T H E D I S T R I B U T I O N O F B L U E B L A C K
P O L YT H E N E B A G S :
T O P R E V E N T C O 2 F R O M T H E S O I L
O R G A N I S M S F R O M G E T T I N G I N T O T H E
B E L L J A R
S O D A L I M E ( C A L C I U M O X I D E ) +
P O T A S S I U M H YD R O X I D E S O L U T I O N =
N E U T R A L I S A T I O N ; N O C O 2

3. E S S E N T I A L
C O N D I T I O N S F O R
P H O T O S Y N T H E S I S
P H O T O S Y N T H E S I S
(1) sunlight
(2) carbon dioxide (raw)
(3) chlorophyll
(4) suitable temperature
(5) water (raw)
(6) enzyme reactions (photolysis)
(7) inorganic materials eg. carbon,hydrogen,oxygen
process in which light energy absorbed by
chlorophyll is transformed into chemical energy
which is then used to synthesise carbohydrates
from water and carbon dioxide.
L I G H T - I N D E P E N D E N T
S T A G E
L I G H T - D E P E N D E N T
S T A G E
hydrogen produced in photolysis is used to
reduce carbon dioxide to carbohydrates eg.
glucose.
light energy is absorbed by chlorophyll and then
converted into chemical energy (food). light energy is
also used to split water molecules into oxygen and
hydrogen atoms also known as photolysis of water
12 H2O — 6 O2 + 24 H 6 CO2 — C6 H12 O6 + 6H2O

9. A factor that affects the rate of photosynthesis but stops the effect
after a certain point or any factor that directly affects or limits a
process if its quantity is altered

10. T E S T F O R E F F E C T O F D I F F L I G H T I N T E N S I T I E S
E S T F O R E F F E C T O F D I F F T E M P E R A T U R E S
P L A C E C U T E N D O F W A T E R P L A N T F A C I N G U P W A R D S I N A T U B E F I L L E D
W I T H S O D I U M H YD R O G E N C A R B O N A T E S O L U T I O N ( B A K I N G S O D A W H E N
H E A T E D ) I T S U P P L I E S C A R B O N D I O X I D E .
T H E N E A R E R T H E L I G H T S O U R C E I S T O T H E B E A K E R , T H E H I G H E R T H E
L I G H T I N T E N S I T Y T H A T T H E P L A N T I S E X P O S E D T O .
A D D I C E C O L D W A T E R T O T H E W A T E R B A T H ( W H I C H I S M E A N T T O K E E P T H E
T E M P E R A T U R E C O N S T A N T ) L E T I C E W A T E R A L T E R T H E T E M P E R A T U R E
D I F F E R E N T L Y.
T E S T F O R E F F E C T O F D I F F C O 2
C O N C E N T R A T I O N S
U S E D I F F E R E N T C O N C E N T R A T I O N S O F S O D I U M H YD R O G E N C A R B O N A T E
S O L U T I O N S ( W H I C H S U P P L I E S C O 2 )

13. large and thin

14. Transport water and mineral satls and manufactured food
Large flat surface to volume and thin to obtain the maximum amount of sunlight
and more carbon dioxide can rapidly reach the inner cells
Holds the lamina away from the stem so that it can obtain sufficient amount of sunlight and air

15. Ensures that the
leaves are not blocking
one another from
sunlight and that each
leaf receives sufficient
light

17. — made up of a single layer of closely packed cells

18. lies between the
upper and lower
epidermis
to maximise absorption of sunlight

19. • Cells are irregular in shape
• Numerous large intercellular air spaces among the cells
allowing rapid diffusion of gases ( main site for gaseous
exchange)
• Cells carry out lesser photosynthesis compared to
palisade layer (fewer chloroplast)
• Cells are covered with a thin film of moisture
• Contains the vascular bundles

24. How?

29. through stomata