1.
Chapter 6 Nutrition
Ong Yee Sing
2017

2.
Content
• Type of nutrition
• Balanced diet
• Malnutrition
• Food digestion
• Formation of faeces and defaecation
• Evaluating eating habits
• The importance of a healthy digestive system
UEC C5
UEC C5
UEC C5

3.
• The importance of macronutrients and micronutrients in plants
• Photosynthesis
• The mechanism of photosynthesis
• The factors affecting photosynthesis
• A caring attitude towards plants
• Technology used in food production
• Technological development in food production
UEC C5
UEC C5

4.
6.1 Type of nutrition
• Nutrition 营养作用
• Nutrients 营养素
• Autotrophic nutrition 自身营养
• Autotroph 自养生物
• Photosynthesis 光合作用
• Photoautotroph 光养生物
• Chemosynthesis 化能合成
• Chemophototroph 化能生物
• Heterotrophic nutrition 异生营养
• Heterotroph 异养生物
• Holozoic nutrition 全动物式营养
• Saprophytism 腐生营养
• Saprophyte 腐生生物
• Parasitism 寄生营养
• Parasite 寄生物
• Host 宿主

5.
6.2 Balanced diet
• The necessity for a balanced diet
• Daily energy requirement
• Nutrient content in food
• Selection of an appropriate balanced diet

6.
The necessity for a balanced diet
• Living organisms obtain nutrients from their diets.
• The foods that constitute a balanced diet should contain the major
nutrients which include:
• Carbohydrates
• Proteins
• Lipids
• Vitamins
• Minerals
• Roughage or dietary fibre
• Water
• These nutrients must be taken in the correct proportion
• To meet the daily energy requirement of an individual
• To provide the necessity nutrients for growth and tissue repair
• For maintaining health

7.
Daily energy requirement
• A balanced diet is able to fulfil the daily energy
requirement.
• This energy is generated by the oxidation of
molecules obtained from the food during
respiration.
• The energy content of a substances can be
determined by burning a known mass of food in
the presence of oxygen in a bomb calorimeter.

8.
Energy content in food
• The energy value of the food is the amount of heat generated from
the combustion of one gram of food.
• The unit of energy value is joule per gram (J g-1).
• 4.2 joules of energy are needed to raise the temperature of 1 g of
water by 1°C.
• The energy value of nutrient
• Carbohydrates – 16.7 kJ/g
• Protein – 22.2 kJ/g
• Lipid – 37.6 kJ/g

9.
Factors that effecting the daily energy
•Age
• Growing children and adolescents
require more energy compare to
adults
•Sex
• Adult males require more energy
than adult female.Men generally are
physically more active and have less
body fat.
•Occupation
• People that involve heavy physically
work require more energy than those
who are physically inactive.
•Climate
• People who live in cold countries
require more energy to keep their
body warm,compare to those in the
tropics.
• Body size/weight
• An individual of bigger size require
more energy than another of smaller
size.
•Lifestyle
• People who indulge in sports
activities require more energy than
those who lead a sedentary life.

10.
Vitamins
• The group of a complex non-
protein organic compounds which
are needed in relatively small
quantities by living organism.
• Provide no energy but are essential
for maintenance of good health
and efficient metabolism.
• Can be divided into:
 water-soluble vitamins : B and C
• cannot be stored in the body
• have to be constantly supplied in the
daily diet
 Fat-soluble vitamins : A,D,E and K
• can be stored in the body fat

11.
VITAMINS SOURCES FUNCTIONS
A EGG, MILK,CARROT, PAPAYA •For growth and promote healthy skin
•For good night vision
B EGG, YEAST, LIVER, NUTS, TOMATO •Promotes the effective functioning of
the nervous system
•Controls the supply of carbohydrates to
the muscle and nerve cells
C GREEN VEGETABLES, TOMATO, LIME •Increases immunity against diseases
•Promotes healthy skin
D EGG, MILK, COD LIVER OIL •Helps in the absorption of calcium and
phosphorus in the small intestines
E VEGETABLE OIL, EGG, LIVER, MILK,PALM OIL •Maintains a healthy reproductive system
K SUNFLOWER SEEDS, MAIZE •Necessary for the clotting of blood

12.
Minerals
• Simple inorganic nutrients which must be obtained through the diet,
either from food or dissolved in drinking water.
• Provide no energy but are vital for the maintenance of good health.
• Macrominerals/major minerals are required in relatively large
quantities.
• Calcium, phosphorus, sodium, potassium, chlorine
• Microminerals are required in trace amounts of less than 20mg per
day.
• Ferum, iodine, zinc

13.
MINERALS SOURCES FUNCTIONS
CALCIUM MILK, ANCHOVIES, CHEES, EGG • Formation of strong bones and
teeth
• Helps in clotting in blood
SODIUM COMMON SALT • Necessary constituent of blood
plasma
IRON MILK, LIVER, MEAT, EGG • Builds haemoglobin of red
blood cells
IODINE SEAFOOD • Necessary for the functioning of
the thyroid gland
PHOSPHORUS MILK, FISH, EGG • Formation of strong bones and
teeth
POTASSIUM MILK, EGG • For muscles contraction
• Helps to maintain the balance
of blood and tissue

14.
Roughage/dietary fibre
• Refer to the parts of plants that cannot be digested.
• The sources of roughage are vegetables, fruits, nuts and wholemeal
grains.
• Functions
• Helps to stimulate peristalsis and the muscle movement of the small and big
intestines
• Helps to lower blood cholesterol
• Prevent obesity, diabetes mellitus and heart diseases
• Deficiency of roughage in our diet causes constipation and other
disorders of the large intestine.

15.
Human require ~ 25 – 50 g of roughage per day.

16.
Water
• Water is very essential to the survival of
human as all metabolic reactions take place
in solution.
• Water makes up about 70% off the total
body weight.
• Functions of water
• Controlling the body temperature
• Removing excretory products
• Controlling the concentration of blood
• Transporting foods during digestion
• As a lubricant
• As a medium for biochemical reactions in the
body
• Failure to replace the lost water results in
dehydration. A series loss of water can be
fatal.

17.
Selection of an appropriate balanced diet
• Athletes
• CARBOHYDRATES: provide extra energy
• PROTEINS :build up muscles
• Reduce intake of fats
• Vegetarians
• Eat a variety of vegetables, fruits,
cereals and beans
• Take a vitamin B12 supplement as it only
found in animal sources
• Pregnant women
• PROTEINS: the building of the foetal tissue
• CALCIUM & PHOSPHORUS: build the
bones
• IRON: for the foetus to make red blood cells
• Cut down on sugar and fats
• Infants
• PROTEINS: build soft tissue
• CALCIUM & PHOSPHORUS: build bones and
teeth
• CARBOHYDRATES: provide energy for
growth
• Breast milk is the best food
• Children
• Need energy-rich food
• PROTEINS, IRON, CALCIUM &
PHOSPHORUS : for their rapid growth
• Teenagers
• GIRLS: IRON: making red blood cells to replace
those lost during their menstrual periods
• Cut down on oil-rich food
• A diet of cereals, lean meat, fish,
vegetables and fruits

18.
6.3 Malnutrition
• Results from taking an unbalanced diet in which certain nutrients are
lacking , in excess, or in the wrong proportions.
• Malnutrition leads to health problems and diseases.

19.
The effect of malnutrition
• Kwashiorkor 恶性营养不良: Stunted growth , muscles that waste
away, diarrhoea ,oedema which causes the belly to swell, loss of
appetite and apathy.
• Marasmus 消瘦: lacks of energy-providing too .The child become
very thin and looks old for his age.
DEFICIENCY
IN PROTEINS
• Rickets 佝偻病Gōulóubìng: CALCIUM & PHOSPHORUS. The
child’s bones are soft and can bend out of shape.
• Osteoporosis 骨质疏松: CALCIUM,VITAMIN D & PHOSPHORUS.
The elderly ’s bones become porous and break easily.
DEFICIENCY
IN MINERALS
• Rickets 佝偻病: VITAMIN D.
• Scurvy 坏血病: VITAMIN C .Symptoms: bleeding and swollen
gums.
• Sterility 不育症: VITAMIN E.
• Night blindness 夜盲症: VITAMIN A
DEFICIENCY
IN VITAMINS

20.
DEFICIENCY IN PROTEINS DEFICIENCY IN MINERALS

21.
DEFICIENCY IN VITAMINS

22.
• Obesity 痴肥: An obese person is at higher risk of developing
high blood pressure and heart problems.
• Atherosclerosis 动脉粥样硬化: A person leads to high blood
pressure, puts a strain on the heart and increase the risk of
stroke.
EXCESSIVE INTAKE
OF LIPIDS
• Obesity
• Diabetes mellitus 糖尿病: A higher risk of stroke, heart
diseases and kidney failure.
EXCESSIVE INTAKE OF
CARBOHYDRATES
• Gout 痛风: Raise the level of uric
acid in the blood.EXCESSIVE INTAKE OF PROTEINS
• The liver and kidney will be damaged : VITAMIN A,D,E
& K
• an upset stomach : VITAMIN C
EXCESSIVE INTAKE OF
VITAMINS
• High blood pressure : COMMON SALT
• Damage the liver and kidneys : IRON
• Bone formation in soft tissues & promotes formation of kidney stones :
CALCIUM
EXCESSIVE
INTAKE OF
MINERALS

23.
Ways to reduce the chance of contracting
certain health problems due to one’s diet
• Cutting down on the intake of saturated fats,red meat and organs.
• Cutting down on the intake of salt.
• Taking enough dietary fibre, which can help lower blood cholesterol
level.
• Having enough sleep daily.
• Managing stress well.
• Exercising regularly.
• Abstaining from smoking and alcohol, which cause high blood
pressure.

24.
6.5 Food digestion
• Refer UEC Chapter 5
• Extra vocab:
• Bolus 食团: a ball-like mixture of food and saliva that forms in the mouth
during the process of chewing
• Chyme 食糜: the semi-fluid mass of partly digested food that is expelled by
the stomach into the duodenum
• Erepsin 肠肽酶: enzymes that digest peptones into amino acids
• Cud 反刍的食物: a portion of food that returns from a ruminant's stomach to
the mouth to be chewed for the second time

25.
6.6 Formation of faeces and defaecation
• Function of colon:
• Expel faeces through peristalsis.
• Faeces contain water, undigested food substances, indigestible fibre (cellulose), dead
cells, waste products (bile pigments, toxic).
• Provide a habitat for bacteria that maintain homeostasis in the alimentary
canal.
• Defacecation is the process of elimination of faeces.
• Controlled by the muscle around the anus
• Due to increase pressure on the rectum
• Problems related to defaecation
• Constipation 便秘
• Haemorrhoids 痔核
• Colon cancer 结肠癌

26.
6.7 Evaluating eating habits
• We should
practice good
eating habit and
follow a balanced
diet.
• Processed food
contain food
labels that
provide
information on
the nutrition
content.

27.
Health problems related
to eating habits
• Obesity 痴肥
• Gastritis 胃炎
• Gastric ulcer 胃溃疡
• Anorexia nervosa 神经性厌食症
• Bulimia 贪食症

28.
Obesity 肥胖症
• Excessive amount of body fat
• Result from lack of balance between food intake and energy
expenditure
• May lead to cardiovascular disease 心血管疾病, diabetes mellitus

29.
Gastritis 胃炎
• Inflammation of the epithelium of the stomach
• Result from irregular food intake that leads
erosion of the mucosal covering of the
epithelial tissue by the gastric juice
• May lead to gastric ulcer 胃溃疡: open sores疮
that develop on the lining of the stomach
Gastritis (this micrograph shows a result
of Helicobacter pylori infection)
Normal

30.
Anorexia nervosa神经性厌食症
• A psychiatric diagnosis that
describe an eating disorder
characterized by a low weight,
fear of gaining weight, a strong
desire to be thin and food
restriction.
• Voluntary starvation, purging 净空
行为, vomiting, excessive exercise,
drugs
• May lead to disturbed
electrolyte balance (esp.
phosphate – heart failure,
muscle weakness, immune
dysfunction, death), stunted
growth, low essential hormones,
chronically increased cortisol
levels, osteoporosis.

31.
Bulimia nervosa 贪食症/暴食症
• A psychiatric diagnosis that
describe an eating disorder
characterized by recurrent binge
eating 暴饮暴食 followed by
purging 净空行为 (e.g. vomiting,
fasting, taking laxatives, enemas,
excessive exercise).
• May lead to organ damage, teeth
damage etc.

32.
6.4 The importance of macronutrients and
micronutrients in plants
• Mineral nutrients are essential chemical elements
required by plants.
• Macronutrients 主要营养物质 are required in
larger amount than micronutrients 微量营养物质.
• Deficiency in macronutrients that can be obtained
from the air such as oxygen, carbon, and hydrogen
rarely occurs.
• Determination of the requirement of nutrients of a
plant seeding can be carried out through the
Knop’s solution by eliminating it from this solution.

33.
Macronutrient
Elements Functions Deficiency Symptom
Potassium (K) • Helps in the building of protein, fruit quality and reduction of diseases.
• A cofactor for many enzymes.
• Maintain turgidity in plants.
• Reduced protein synthesis.
• Yellow-edges leaves.
• Premature death of plants.
Calcium (Ca) • Synthesis of middle lamella.
• Formation of spindle fibres.
• Stunted growth.
• Distorted and cupped leaves.
• Yellowing in the regions between the veins.
Magnesium
(Mg)
• Magnesium is part of the chlorophyll.
• It also helps activate many plant enzymes.
• It involves in carbohydrate metabolism.
• Yellowing in the regions between the veins
of mature leaves.
• Red spot on leaf surfaces.
• Leaves become cupped.
Nitrogen (N) • Nitrogen is a part of all living cells and is a necessary part of all
proteins, enzymes and metabolic processes involved in the synthesis
and transfer of energy.
• Nitrogen is a part of chlorophyll, the green pigment of the plant that is
responsible for photosynthesis.
• Helps plants with rapid growth, increasing seed and fruit production
and improving the quality of leaf and forage crops.
• Chlorosis 褪绿 - general yellowing of older
leaves (bottom of plant) due to inhibition of
chlorophyll synthesis
• The rest of the plant is often light green
Phosphorus (P) • Synthesis of nucleic acids, ATP and phospholipids.
• Acts as a coenzyme in photosynthesis and respiration.
• Poor root growth.
• Formation of dull, dark green leaves.
• Red or purple spot on old leaves.
Sulphur (S) • Components of certain amino acids, vitamin B and some coenzymes. • Yellowing of the affected leaves or entire
plants.

34.
Micronutrient
Elements Functions Deficiency Symptom
Copper (Cu) • Enzyme component.
• Nitrogen metabolism and photosynthesis.
• Reproductive growth and flower formation in plants.
• Death tips of young shoots.
• Brown spot on terminal leaves.
• Stunted growth.
Iron (Fe) • Cofactor in synthesis of chlorophyll.
• Essential for young growing parts.
• Yellowing of young leaves.
Manganese
(Mn)
• Activator of enzymes in photosynthesis, respiration of nitrogen
metabolism.
• A network of green veins on a light green
background.
• Brown or grey spots between the veins.
Molybdenum
(Mo)
• Nitrogen fixing.
• Reduction of nitrates during protein synthesis.
• Chlorosis in the areas between the veins of
mature leaves.
• Pale green leaves.
• Reduction in crop yield.
Zinc (Zn) • Leaf formation.
• Synthesis of auxin (growth hormone).
• Cofactor in carbohydrate metabolism.
• Mottled leaves with irregular areas of
chlorosis.
• Retarded growth.
Boron (B) • Aid in calcium ions uptake by roots, translocation of sugars,
carbohydrate metabolism, germination of pollen grains.
• Required for normal mitotic division.
• A cofactor in chlorophyll synthesis.

35.
6.10 Photosynthesis
• Brief history
• Leaf structure and function
• Adaptation of plants from different habitats to carry out
photosynthesis

36.
Leaf structure
• Leaf mosaic 叶镶嵌 is a growth arrangement where the cells overlap
each other as little as possible to receive as much light as possible to
optimize photosynthesis
Air space
角质层
下表皮
上表皮
栅栏叶肉
海绵叶肉
角质层
气孔
保护细胞
维管束鞘
木质部
韧皮部
叶脉
气室
中脉
叶片
气孔
叶脉叶柄

37.
Leaf Functions
• Air space - intercellular gaps within the spongy mesophyll. These gaps are
filled with gas that the plant uses (carbon dioxide - CO2 ) and gases that the
plant is expelling (oxygen - O2, and water vapor).
• Chlorophyll - a molecule in leaves that can use light energy from sunlight to
turn water and carbon dioxide gas into sugar and oxygen (this process is
called photosynthesis). Chlorophyll is magnesium-based and is green.
• Cuticle - the waxy, water-repelling layer on the outer surface of a leaf that
helps keep it from dying out (and protect it from invading bacteria, insects,
and fungi). The cuticle is secreted by the epidermis (including the guard
cells) and is often thinner on the underside of leaves. The cuticle is
generally thicker on plants that live in dry environments.
• Epidermis - the protective, outler layer of cells on the surface of a leaf. The
guard cells (and stoma) are part of the epidermis. The surface of many
leaves is coated with a waxy cuticle which is secreted by the epidermis.

38.
• Guard cell - one of a pair of sausage-shaped cells that surround a stoma (a pore
in a leaf). Guard cells change shape (as light and humidity change), causing the
stoma to open and close.
• Palisade mesophyll - a layer of elongated cells located under the upper
epidermis. These cells contain most of the leaf's chlorophyll, converting sunlight
into usable chemical energy for the plant.
• Spongy mesophyll - the layer below the palisade mesophyll; it has irregularly-
shaped cells with many air spaces between the cells. These cells contain some
chlorophyll. The spongy mesophyll cells communicate with the guard cells
(stomata), causing them to open or close, depending on the concentration of
gases.
• Stoma - (plural stomata) a pore (or opening) in a plant's leaves where water
vapor and other gases leave and enter the plant. Stomata are formed by two
guard cells that regulate the opening and closing of the pore. Generally, many
more stomata are on the bottom of a leaf than on the top.
• Vein (vascular bundle) - Veins provide support for the leaf and transport both
water and minerals (via xylem) and food energy (via phloem) through the leaf and
on to the rest of the plant.
Leaf Functions

39.
Adaptation of plants from different habitats
to carry out photosynthesis
• Plans adapted to extreme environmental condition may have
modification in the distribution of stomata and chloroplasts.
Examples Habitat Distribution of stomata Distribution of
chloroplasts
Mesophytes 中生植物
e.g. hibiscus
Terrestrial environment
that are neither
particularly dry nor
particularly wet
Many stomata on the
lower surface of the leaf
Many chloroplasts in the
palisade mesophyll cells,
spongy mesophyll cells
and guard cells.
(Succulent 多肉植物)
xerophytes 旱生植物
e.g. cacti
Terrestrial environment
that have little liquid
water available
Reduced leaves with
sunken stomata.
The stem have many
chloroplasts.
Hydrophytes 水生植物
e.g. water lilies, Hydrilla
sp.
Aquatic environment Stomata are found on the
upper surface of the leaf
or no stomata in
submerged plants.
Many chloroplasts in the
palisade mesophyll or in
all parts of the plants in a
submerged plants.

40.
Mesophytes 中生植物

41.
Succulent xerophytes 多肉旱生植物

42.
Hydrophytes 水生植物

43.
Floating plants
• Floating leaves are generally tough because they
have to withstand the weather and water
movement.
• The chloroplasts are restricted to the upper
surface of the leaves which are the only surface
to be well lit.
• Stomata are also found only on the upper surface
of the leaf.
• This upper surface often has a thick waxy cuticle
to repel water and help to keep the stomata
open and clear.
• Air-filled internal cavities are also often present.
• Weak stems produce a massive floating canopy
of leaves as water provides all the necessary
support.

44.
Submerged plants
• The presence of little or no mechanical
strengthening tissue in stems and leaf petioles.
• The epidermal (outermost) layer shows very little, if
any, sign of cuticle formation. All the surface cells
appear to be able to absorb water, nutrients and
dissolved gases directly from the surrounding water.
• Xylem is often greatly reduced, if not absent.
• There are also no stomata on the leaves.
• Roots are often also reduced and their main
function is anchorage. The root hairs which function
in absorption are often absent and roots themselves
may be entirely dispensed with (e.g. Bladderwort).
• The submerged leaves are often highly dissected or
divided to maximise surface area for absorption and
photosynthesis and minimises water resistance.
• Air-filled cavities often extend throughout the leaves
and stems of aquatic plants, providing an internal
atmosphere.
Floating and submerged plants

45.
6.11 Mechanism of photosynthesis

46.
COMPARISON OF LIGHT REACTION & DARK REACTION
LIGHT REACTION 光反应 DARK REACTION 暗反应
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
water
Substance required in reaction is
carbon dioxide

47.
6.12 The factors affecting photosynthesis
• Light intensity
• Concentration of carbon dioxide
• Temperature
• Photosynthesis rate will be
different throughout the day and
the year.
• There factors can be controlled
artificially in green houses.

48.
6.13 A caring attitude towards plants
• The importance of photosynthesis
• Carbon fixation
• Coal
• Oxygen

49.
6.14 Technology used
in food production
• To improve the quality & quantity
of food production in Malaysia
through :
• Direct seeding
• Hydroponics
• Aeroponics
• Selective breeding
• Tissue culture
• Genetic engineering
• Soil management
• Biological control

50.
• Direct seeding 通过植被直接进行植物播种
• Sow the seed directly into
undisturbed soil.
• Plants grow faster as roots are not
damaged during transplantation.
• Hydroponics 水耕栽培
• Grow of plant using aerated culture
solution which contain all required
nutrients.
• Less space and pesticides are required.

51.
• Aeroponics 气耕
• A modification of hydroponics
where the culture solution is
sprayed directly to the roots of the
plants.
• Less space and pesticide is
required.
• Selective breeding 优育
• Selection of parents that can
produce offspring which desirable
traits.
• Produce crops and offspring with
better quality and quantity.
Big kernal
Thick mesocarp
Thin endocarp
Big kernal
Thick mesocarp
Thin endocarp

52.
• Tissue culture组织培养
• Growth of tissue
and/or cells on a
growth media.
• Mass production of
desirable strain and
clones
• Genetic engineering基因工程
• The deliberate modification
of the characteristics of an
organism by manipulating
its genetic material.
• Quick incorporation of
desirable traits.

53.
• Soil management土壤管理
• All activities used to
protect soil and enhance its
performance
• Reduce soil erosion, leaching
• Biological control生物防治
• The control of a pest by the
introduction of a natural enemy or
predator.
• Cost-effective and do not pollute
the environment.
Ladybird eating Aphid

54.
6.15 Technological development in food
processing
• The necessity for food processing:
• Destroying microorganisms
• Extending the lifespan of food
• Avoiding food wastage
• Diversifying the uses of food, like
milk and dairy products
• Ensuring sufficient food supply
because processed food can last
longer
• Food can be easily sent to places
with insufficient food supply

55.
Food processing methods
• Cooking
• to kill the bacteria
• Using salt, sugar & vinegar
• Osmosis for dehydration – condition
unflavourable for bacteria growth
• Fermentation 发酵
• yeast turns glucose into ethanol + CO2
• Drying
• dehydration
• Pasteurisation 巴氏杀菌
• heated to certain temperature and rapid
cooling
• Canning
• sterilised at high temperature >120 °C in
vacuum - kill bacteria and prevent bacteria
from growing
• Refrigeration
• temperature low -15°C - slow down the
action of microorganism