class: name: date: 5 food and humansbio662.dyndns.info/dse/ws/ws_ch05_e.pdf · humans and many...

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New Senior Secondary Mastering Biology Oxford University Press 2014 (Second Edition)

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5 Food and humans

5.1 Modes of nutrition (Book 1A, p. 5-3)

� Plants can make their own food by photosynthesis. This mode of nutrition is called

(1) _______________ _______________ (自養營養) and plants are (2) _______________

(自養生物).

� Humans and many other organisms have to take in organic matter from their surroundings.

This mode of nutrition is called (3) _______________ _______________ (異養營養).

Organisms that carry out this mode of nutrition are called (4) _______________ (異養生物).

5.2 The food requirements of humans (Book 1A, p. 5-4)

A Why do we need food? (Book 1A, p. 5-4)

� Food provides us with (1) _______________ for supporting daily activities and keeping us

warm. It provides us with raw materials for (2) _______________ and repair of body tissues.

It also provides us with substances that are important for maintaining (3) _______________.

B Food substances (Book 1A, p. 5-4)

� Food contains seven types of food substances (食物物質). They are (4) _____________ (碳水化合物),

(5) _______________ (脂質), (6) _______________ (蛋白質), (7) _______________ (礦物質),

(8) _______________ (維生素), (9) _______________ _______________ (食用纖維) and water.

1 Carbohydrates

� Carbohydrates are organic substances. They are made up of (10) _______________ (C),

(11) _______________ (H) and (12) _______________ (O) atoms. The H : O ratio is 2 : 1.

◄ Structure of a glucose molecule

(C6H12O6), a carbohydrate


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� Classification of carbohydrates:

Type of carbohydrate and its feature Example Food source

(15) _______________

(葡萄糖) and fructose (果糖)

Fruits and

honey

Monosaccharides (單糖)

� The simplest form of carbohydrates

� Taste sweet and are (13) ______________

(soluble / insoluble) in water

� Are (14) _______________ sugars

Galactose (半乳糖) Milk and dairy

products

(21) _______________

(麥芽糖): formed by

condensation of two glucose

molecules

Germinating

barley

Sucrose (蔗糖): formed by

condensation of

(22) ______________ and

(23) ______________

Sugar cane and

sugar beet

(16) _______________ (雙糖)

� Formed by (17) _______________ (縮合) of

two monosaccharide molecules

� Can be broken down into monosaccharides

by (18) _____________ (水解)

� Taste sweet and are (19) ______________

(soluble / insoluble) in water

� Are reducing sugars except

(20) _______________ Lactose (乳糖): formed by

condensation of

(24) ______________ and

(25) ______________

Milk and dairy

products

Starch Potatoes and

cereal products

(29) _______________

(糖原): the storage form of

carbohydrates in animals

---

(26) _______________ (多糖)

� Long chains of (27) _______________

joined by condensation

� Do not taste sweet and are

(28) _______________ (soluble / insoluble)

in water Cellulose (纖維素) Plant products

� Functions of carbohydrates:

- As the main (30) _______________ source.

- (31) _______________ is directly broken down in respiration to release energy.

- (32) _______________ is the storage form of carbohydrates in plants.

- Glycogen is stored in the liver or muscles as energy (33) ________________.

- (34) ________________ is a source of dietary fibre.


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2 Lipids

� Lipids are organic substances made up of carbon, hydrogen and oxygen atoms, but the H : O

ratio is much (35) _______________ than 2 : 1.

� Lipids are insoluble in water but soluble in (36) _______________ solvents.

� (37) _______________ (甘油三酯) are the commonest type of lipids. They are formed from the

condensation of three (38) _______________ _______________ (脂肪酸) molecules and one

(39) _______________ (甘油) molecule.

� Triglycerides can be classified into:

- (40) ____________ (脂肪), which are solids at room

temperature and come mainly from animals

- (41) ____________ (油), which are liquids at room

temperature and come mainly from plants.

▲ Foods rich in fats and oils

� Functions of lipids:

- Stored in (42) _______________ tissues (脂肪組織) under the skin as (43) _______________

_______________ (皮下脂肪) or around internal organs, which act as:

� energy reserves

� an (44) _______________ to reduce heat loss

� a shock (45) _______________ to protect the internal organs.

- Involved in transporting and storing (46) _______________-soluble vitamins.

- Involved in making cell membranes and some (47) _______________ (激素) .

condensation

hydrolysis

3 fatty acid molecules (can be the same or different)

1 glycerol molecule

1 triglyceride molecule

3 water molecules

▲ The formation and breakdown of a triglyceride molecule


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3 Proteins

� Proteins are organic substances made up of carbon, hydrogen, oxygen and (48) ___________

atoms. Some proteins also contain sulphur.

� (49) _______________ _______________ (氨基酸) are the basic building blocks of proteins.

� A (52) _______________ (二肽) is formed from condensation of two amino acids. It can be

broken down into amino acids by (53) _______________.

� Combination of a dipeptide with other amino acids forms a (54) _______________ (多肽).

A protein may consist of one or more polypeptides.

� Our body needs 20 types of amino acids to build up

various proteins. The amino acids can be classified

into:

- (55) _______________-_______________

amino acids (非必需氨基酸): can be produced by

our body

- (56) _______________ amino acids (必需氨基酸):

have to be obtained from the diet.

▲ Foods rich in proteins

� Functions of proteins:

- For growth and (57) _______________ of body tissues.

- Form enzymes and (58) _______________ (抗體); some hormones are protein in nature.

- Amino acids are broken down to release (59) _______________ if the carbohydrates

and lipids stored in the body are used up.

� A deficiency of protein may lead to (60) _______________ (蛋白缺乏症).

(50) _____________

group (氨基)

(51) _______________

group (羧基)

▲ Basic structure of an amino acid


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4 Minerals

� Minerals are (61) _______________ (organic / inorganic) food substances. They are needed

in (62) _______________ (small / large) amounts compared with carbohydrates, fats and

proteins.

� Minerals have no (63) _______________ value, but are important in (64) _______________

many metabolic reactions and building body tissues.

Mineral and its function Food source Deficiency disease

Calcium (鈣)

� For the formation of bones and

(65) _______________

� Important in blood clotting (凝血),

(66) _______________ contraction and

sending messages in the nervous system

Canned sardines,

milk and dairy

products, some

green vegetables

and tofu

(67) _______________

(軟骨病) in children

Iron (鐵)

� For the formation of (68) _______________

in red blood cells

Beef, liver, beans

and spinach

(69) _______________

(貧血)

5 Vitamins

� Vitamins are (70) _______________ (organic / inorganic) food substances. They are needed in

small amounts.

� Vitamins have no energy value, but they help regulate many metabolic reactions.

Vitamin and its function Food source Deficiency disease

Vitamin A (lipid-soluble)

� Helps form a (71)

_______________ in the retina

(視網膜)

� Keeps the skin, the cornea (角膜)

and the lining of the alimentary

canal and breathing system healthy

Fish liver oils, liver,

dairy products, eggs,

vegetables and fruits

containing

(72) _______________

(胡蘿蔔素)

� (73) _______________

_______________ (夜盲症)

� Drying up of the cornea

and skin

� Easy (74) ______________

of the lining of the lungs

and trachea

co

nt.


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Vitamin and its function Food source Deficiency disease

Vitamin C (water-soluble)

� Helps the growth and repair of

(75) _______________ tissues

(結締組織)

� Promotes the absorption of

(76) _______________

� Helps the immune system (免疫系統)

work properly

Fresh vegetables and

fruits

(77) ______________ (壞血病)

Vitamin D (lipid-soluble)

� Promotes the absorption of

(78) _______________ and

phosphate ions

Fatty fish, fish liver

oil, liver and egg

yolks

Rickets in children

6 Dietary fibre

� Dietary fibre is an (79) _______________ (organic / inorganic) food substance. It consists of

mainly (80) _______________ from plant cell walls.

� Dietary fibre does not provide energy.

� An adequate intake of dietary fibre is important to health because:

- it adds bulk to food to stimulate (81) _______________ (蠕動)

- it holds a lot of water to allow (82) _______________ to remain soft.

� A deficiency of dietary fibre may lead to (83) _______________ (便秘) and even

(84) _______________ cancer (結腸直腸癌).

7 Water

� Functions of water in the body:

- As a solvent.

- As a (85) _______________ for chemical reactions.

- As a transport medium.

- As a (86) _______________ agent to help regulate body temperature.

- As a reactant.


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5.3 Food tests (Book 1A, p. 5-19)

Food substance Food test Positive result

Glucose Using glucose test paper Depends on the colour chart on the packing of

the test paper

Reducing sugar (1) _______________ test

(本立德測試)

A (2) _______________-_______________

precipitate is formed.

Starch (3) _______________ test Iodine solution changes from brown to

(4) _______________-_______________.

Lipid Grease spot test A (5) _______________ spot is left, which

disappears after immersing it in an

(6) _______________ solvent.

Protein Using protein test paper Depends on the colour chart on the packing of

the test paper

Vitamin C Using DCPIP solution (7) _______________ of the DCPIP solution.

� Go to

Practical 5.1 Detection of food substances by food tests

(Book 1A, p. 5-19; Practical Workbook for SBA 1A, p. 5-1)

Practical 5.2 Investigation of the food substances in common foodstuffs


Practical 5.3 Design an investigation to compare the amount of vitamin C in different fruits and

vegetables


Practical 5.4 Design an investigation to study the effect of boiling on the amount of vitamin C in

vegetables



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5.4 Balanced diet (Book 1A, p. 5-25)

A The food pyramid (Book 1A, p. 5-25)

� A (1) _______________ _______________ (均衡膳食) consists of all the food substances in

the right (2) _______________ and (3) _______________.

� We can make use of the (4) _______________ _______________ (食物金字塔) as a guideline to

plan a balanced diet. In the food pyramid, foods are classified into six food groups:

Food group Relative amount to be eaten

I Cereals and grains a Eat less

II Dairy products b Eat moderately

III Fat, oil, salt and sugar c Eat more

IV Fruits d Eat the most

V Meat, eggs and beans

VI Vegetables

I: (5) _________ II: (6) ________ III: (7) ________

IV: (8) _________ V: (9) ________ VI: (10) ________

▲ Food pyramid

fat, oil, salt and sugar

dairy products meat, eggs and beans

vegetables fruits

cereals and grains

We should also take in 6–8 glasses of fluid every day.


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B Factors affecting our dietary requirements (Book 1A, p. 5-26)

Factor Effect on dietary requirement

Age

� Children and teenagers need a large amount of (11) _______________,

calcium and iron for building body tissues.

� Children require the greatest amount of (12) _______________ per unit

body mass because they have the highest growth rate and the highest metabolic

rate. Children also have the highest rate of (13) _______________ loss as their

surface area to volume ratio is the highest among all age groups.

Sex

� After puberty, males generally need (14) _______________ (more / less)

energy than females. This is because males usually have a higher metabolic

rate due to their (15) _______________ (larger / smaller) body size. Moreover,

males have (16) _______________ (more / less) fat under the skin. They lose

heat more rapidly through the body surface.

� Males need more (17) _______________ than females for the growth and

repair of muscles.

� Females need more (18) _______________ than males to replace the loss

during (19) _______________ (月經).

Level of

activity

� People who are more physically active need more energy for muscular

activities.

Body

status

� Pregnant women need more energy and proteins for the growth of the

(20) _______________ (胎兒). They also need more (21) _______________ for

the formation of foetal red blood cells.

� Breast-feeding mothers need an extra supply of various types of nutrients for

(22) _______________ production.

C What health problems may arise if we eat too little or too much? (Book 1A, p. 5-28)

� (23) _______________ _______________ (神經性厭食) is a disease of under-eating. Patients

with this disease refuse to eat because they are afraid of gaining weight. They may become

seriously weak.

� If we take in more energy than we need, we may become (24) _______________ (過重). The

condition of being seriously overweight is called (25) _______________ (肥胖症).


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Answers

Ch 5 Food and humans

5.1 1 autotrophic nutrition 2 autotrophs 3 heterotrophic nutrition

4 heterotrophs

5.2 1 energy 2 growth 3 health 4 carbohydrates 5 lipids

6 proteins 7 minerals 8 vitamins 9 dietary fibre 10 carbon

11 hydrogen 12 oxygen 13 soluble 14 reducing 15 Glucose

16 Disaccharides 17 condensation 18 hydrolysis 19 soluble 20 sucrose

21 Maltose 22 glucose / fructose 23 fructose / glucose 24 glucose / galactose 25 galactose / glucose

26 Polysaccharides 27 monosaccharides 28 insoluble 29 Glycogen 30 energy

31 Glucose 32 Starch 33 reserve 34 Cellulose 35 greater

36 organic 37 Triglycerides 38 fatty acid 39 glycerol 40 fats

41 oils 42 adipose 43 subcutaneous fat 44 insulator 45 absorber

46 lipid 47 hormones 48 nitrogen 49 Amino acids 50 amino

51 carboxyl 52 dipeptide 53 hydrolysis 54 polypeptide 55 non-essential

56 essential 57 repair 58 antibodies 59 energy 60 kwashiorkor

61 inorganic 62 small 63 energy 64 regulating 65 teeth

66 muscle 67 Rickets 68 haemoglobin 69 Anaemia 70 organic

71 pigment 72 carotene 73 Night blindness 74 infection 75 connective

76 iron 77 Scurvy 78 calcium 79 organic 80 cellulose

81 peristalsis 82 faeces 83 constipation 84 colorectal 85 medium

86 cooling

5.3 1 Benedict’s 2 brick-red 3 Iodine 4 blue-black 5 translucent

6 organic 7 Decolourization

5.4 1 balanced diet 2 amounts / proportions 3 proportions / amounts

4 food pyramid 5 d 6 b 7 a 8 c

9 b 10 c 11 proteins 12 energy 13 heat

14 more 15 larger 16 less 17 proteins 18 iron

19 menstruation 20 foetus 21 iron 22 milk

23 Anorexia nervosa 24 overweight 25 obesity

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