1. CHAPTER 6 :
NUTRITION
6.9 Macronutrients &
Micronutrients in Plants

2. LEARNING OUTCOMES
• List elements required by
plants,
• Classify elements required
by plants based on the
amount needed,
• Relate the effects of
macronutrient deficiency in
plants.
• Explain the function of each
macronutrient in plants,
• State the function of
micronutrients & effects of
micronutrient deficiency in
plants.

3. •M ACRO nut r i ent s : n e e d e d i n
L ARGER q u an t i t i e s
• Car b o n , Hyd r o g e n , Ox yg e n ,
Ph o s p h o r o u s , Po t as s i u m
( Kal i u m) , Cal c i u m, Mag n e s i u m
& Su l phu r.
• M CRO
I nut r i ent s : n e e d e d i n
S MAL L ER q u an t i t i e s .
• Bo r o n , Mo l yb d e n u m, Zi n c ,
Man g an e s e , Co p p e r & F e r u m

4. • Wilhelm Knop (scientist)
successfully prepared a
solution which can provide a
plant with all the nutrients it
needs
• The solution is known as Knop’s
Solution.
Calcium nitrate, Ca(NO3)2 0.8g
Potassium nitrate, KNO3 0.2g
Potassium dihydrogen phosphate, KH2PO4 0.2g
Magnesium sulphate, MgSO4 0.2g
Ferum (III) phosphate, FePO4 Trace
Distilled water 1 litre

6. LEARNING OUTCOMES
• Describe the development that leads to
the discovery of photosynthesis,
• State the substances required for
photosynthesis,
• State the substances produced from
photosynthesis,
• Draw & label the cross section of leaf
• State the function of each part of the
leaf with respect to photosynthesis,
• Explain leaf adaptation to optimise
photosynthesis,
• Explain how plants from different
habitats are adapted to carry out
photosynthesis.

7. The Discovery of Photosynthesis
• 1692 – Dutch scientist, Van Helmont carried out
an investigation to study the nutrition of plants.
• He filled a big pot with exactly 91kg of dry soil 
planted a plant (2.4kg)  the surface covered
with a metal sheet with small holes to allow
water to enter  Van watered the plants for 5
years consistently  plant (increased to 75kg),
soil (decreased by 0.057kg)
• Van Helmont concluded that the increase in
weight of the plant came from the water & not
the soil.

8. The Discovery of Photosynthesis
• 1772 – Joseph Priestly carried out an
experiment using mouse, candle & plants.
• The plant had changed the air in the container.
• 1770s – Jan Ingenhouse discovered that a plant
could only change the air container if there was
light. He also discovered that only the green
parts of the plant were able to do so. (light &
chlorophyll both play a part in photosynthesis0
• 1780s – Jean Senebier showed that the plants
gave out oxygen when they were provided with
CO2

9. P H O T O S YN T H E
S Iprocess through
The biochemical
S
which light energy is absorbed
by chlorophyll, and is used to
fuel the synthesis of sugar
molecules
“The process where organic
compounds are synthesised from
water & carbon dioxide in the
presence of sunlight &
chlorophyll.”

10. STRUCTURE & FUNCTION OF
THE PARTS OF A LEAF

11. Adaptations of Leaf for Optimal
Photosynthesis
• The internal structure of a leaf, the shape of a
leaf & the arrangement of leaves on a plants are
all adapted for obtaining optimum light & CO2
• Table 2
• The shape of a leaf is also adapted for
photosynthesis. Most leaves are broad & thin.
• Large surface area enables the leaf to absorb
maximum light & CO2
• The thinness  light & CO2 need not travel too
far to reach every mesophyll cell

12. Adaptations of Leaf for
Optimal Photosynthesis
• Th e ar r an g e me n t o f l e ave s i s
al s o ad ap t e d t o o p t i mi z e
p ho t o s y nt he s i s .
• Mo s t p l an t s s p r e ad o u t t h e i r
l e ave s i n s u c h a way t h at
t h e r e i s mi n i mal o ve r l ap p i n g
k n o wn as l e af mo s ai c 
e ve r y l e af c an r e c e i ve

13. A D A P T A T IO N O F P L A N T S F R O M
D IF F E R E N T H A B IT A T S F O R
P H O T O S YN T H E S IS
• Two main aspects :
– The distribution of stomata
– The distribution of chloroplasts
• Examples :
– Hibiscus : land
– Water lily : water surface
– Hydrilla : in the water
– Cactus : desert

14. 6.11:
THE MECHANISM
OF
PHOTOSYNTHESIS

15. LEARNING OUTCOMES
• To identify the parts of chloroplast
related to photosynthesis,
• To explain the light reaction & dark
reaction of photosynthesis,
• To compare & contrast light reaction
& dark reaction in photosynthesis,
• To relate light reaction with dark
reaction in photosynthesis,
• To write an equation to represent the
process of photosynthesis

16. • Photosynthesis
occurs in in the
chloroplasts of
mesophyll cells &
guard cells of the
leaf.
• Consist of two part :
stroma & grana
• Each granum
contain chlorophyll
that absorb energy
of sunlight

17. • The process of photosynthesis is divided
into two :
– Light reaction
– Dark reaction
• Light reaction : occurs in the granum (contain
chlorophyll) photolysis of water
• Dark reaction : occurs in the stroma (gel-like
matrix – contain enzymes)  CO2 is reduced to
carbohydrate in a process called fixation of CO2
(reduction of CO2)

18. LIGHT REACTION
• Occurs in granum
• Chlorophyll captures light  excites the
electrons of chlorophyll to higher level
• Light energy is used to split the water molecules
 hydroxyl ions + hydrogen ions (photolysis of
water)
sunlight
• 4H2O chlorophyll
4H+ + 4(OH)-
• The hydrogen ions combine with the electrons
released by chlorophyll to from hydrogen atoms
• 4(H)+ + 4 electrons  4(H)

19. LIGHT REACTION
• The hydrogen atom are used in ‘dark reaction’ to
reduce CO2.
• Each hydroxyl ion loses an electron to the
chlorophyll  hydroxyl groups  combine
together to form H2O & O2
• 4(OH)- - 4 electrons  4(OH)
• 4(OH)  2H2O + O2
• Oxygen is released into the atmosphere & later
used for cellular respiration
• Energy released from the excited electrons is
used to form ATP

20. DARK REACTION
• Occurs in the stroma of the chloroplast
• Hydrogen atoms from ‘light reaction’ are
used in dark reaction to reduce carbon
dioxide to basic units of glucose (CH2O)
• Involves a series of complex chemical
reactions which require enzymes
– CO2 + 4(H)  (CH2O) + H2O
• Six units of (CH2O) combine together to
form a molecule of glucose

21. DARK REACTION
• 6(CH2O)  C6H12O6
• Glucose is converted into starch, cellulose,
sucrose & lipids. When combined with
nitrogen  protein
• Overall process :
12H2O + 6CO2 sunlight C6H12O6 + 6O2 + 6H2O
chlorophyll
Water + carbon dioxide sunlight glucose + oxygen + water
chlorophyll

22. COMPARISON OF LIGHT REACTION
& DARK REACTION
LIGHT REACTION DARK REACTION
SIMILARITIES
•Both occur in the chloroplast
•Both involve chemical reactions
•Both are reactions related to photosynthesis
•Both occur during the day
DIFFERENCES
Occurs in granum Occurs in stroma
Requires sunlight Does not require sunlight
Involves photolysis of water Involves reduction of carbon dioxide
Produces water & oxygen Produces glucose
Substance required in reaction is Substance required in reaction is
water carbon dioxide

23. 6. 12 :
FACTORS
AFFECTING
PHOTOSYNTHESIS

24. LEARNING OUTCOMES
• Identify the factors affecting the rate of
photosynthesis,
• Identify the factor that limits the rate
of photosynthesis at different light
intensities,
• Explain the effects of temperature &
concentration of CO2 on the rate of
photosynthesis,
• Explain the difference in the rate of
photosynthesis in plants throughout the
day based on the changes in light
intensity & temperature,
• Identify some ways to meet the need of
increasing the productivity of crops based
on factors affecting the rate of
photosynthesis.

25. CONCENTRATION OF CO2
• Conc. of CO2 in the
atmosphere varies between Effect of concentration of CO2 on the
0.03% to 0.04% rate of photosynthesis
• Light intensity & temperature 10
are kept constant  the rate
of photosynthesis increases 8
rate of photosynthesis
until a saturation point is reach 6
• After this point, any further 4
increase in the conc. of CO2 2
has no effect on the rate of 0
photosynthesis 1 2 3 4 5 6 7 8 9 10 11
concentration of CO2
• Limited by other factors (light
intensity), not enough to
increase the rate of
photosynthesis

26. LIGHT INTENSITY
• Temperature &
concentration of CO2 are Effect of light intensity on the rate of
kept constant, the rate of photosynthesis at different levels of
photosynthesis can be CO2 concentration
increased by increasing the 10
light intensity up to the light
8
saturation point.
• After this point, any further 6
rate of photosynthesis
increase in light intensity 4
has no effect on the rate of 2
photosynthesis (limiting
factor : CO2 conc.) 0
1 2 3 4 5 6 7 8 9 10 11
• Can be increased by karb on d ioksid a tinggi light intensity
increasing the CO2 conc. karb on d ioksid a rend ah

27. TEMPERATURE
• Dark reaction involves
enzymes Effect of temperature on the rate of
• The rate of photosynthesis photosynthesis at different light intensity
increases as the temperature
increase  enzymes more 12
active
10
• Optimum temp. is between
30oC to 35oC 8
• >40oC, the rate of reaction 6
rate of photosynthesis
decrease  enzymes 4
denatured  photosynthesis
2
stops
• If the light intensity is too low, 0
any increase in temperature 1 2 3 4 5 6 7 8
will not increase the rate of temperature
photosynthesis

28. RELATIONSHIP BETWEEN THE RATE OF
PHOTOSYNTHESIS THROUGHOUT THE
DAY WITH THE CHANGES IN LIGHT
INTENSITY & TEMPERATURE
• Closely related & change throughout the
day
• Light intensity high, the temperature is
also high.
• Tropical country, LI & T are at their
maximum at noon time. The rate of
photosynthesis is also maximum.

29. • If temperature increases above 40oC, the rate of
photosynthesis decreases.
• In temperate country (4 seasons), LI & T change
throughout the year.
• Winter : LI & T are very low. Photosynthesis
hardly occurs
• Autumn : the rate of photosynthesis is at its
lowest  plants shed their leaves & light
intensity as well as the temperature are very low
• Summer : LI & T are at their optimum level for
photosynthesis, the rate of photosynthesis is at
its max.

30. • Summer is the best time for agricultural
• To overcome the problem, the plants need
to be planted in greenhouse.
• In a greenhouse, the conc. of carbon
dioxide, temperature & light intensity are
at optimum levels for photosynthesis.
• The rate of photosynthesis is at its
maximum throughout the year, ensure the
crop production throughout the year.

31. 6.13 Practising a Caring Attitude
Towards Plants
• Must be thankful to plants & practise a caring
attitude towards them
• Why?
• Plants produce food as a source of energy for
us, maintaining the oxygen & carbon dioxide
content in atmosphere
• Without plants, there will be more CO2 & less
O2 in the atmosphere  cause global warming
• Not destroy forests @ chop down plants
indiscriminately. Should grow more plants
around us.

32. 6.14 – Technology in Food
Production
• To improve the quality & quantity of food
production in Malaysia through :
– Direct seeding from rice
– Hydroponics & aeroponics
– Breeding
– Tissue culture
– Genetic engineering
– Soil management
– Biological control

33. 6.15 :
TECHNOLOGICAL
DEVELOPMENT
IN FOOD
PROCESSING

34. • Fresh food can last only for a short time,
easily spoilt.
• Need to be processed in order to last
longer
• Technology for food processing :
– Changing raw food materials to other forms
– Adding certain chemical

35. • The necessity for food processing are :
– Destroying m/organisms
– Extending the lifespan of food
– Avoiding food wastage
– Diversifying the uses of food, like milk & dairy
products
– Ensuring sufficient food supply because
processed food can last longer & they can be
easily sent to places with insufficient food
supply

36. FOOD PROCESSING
METHODS
• Cooking (to kill the bad bacteria)
• Using salt, sugar & vinegar (osmosis)
• Fermentation process (yeast is used  glucose
 ethanol + CO2)
• Drying (dehydration)
• Pasteurisation (heated to certain temp and
rapid cooling)
• Canning (sterilised at high temp, above 120oC,
the container is vacuum to kill bacteria,
prevent bacteria from growing)
• Refrigeration (slow down the action of
microorganism, temp low to -15oC)