SUBJECT: SCIENCE FORM: 5

1 . NUTRITION AND GOOD EATING HABITS

1.1 NUTRIENTS

Definition : Chemical substances which all living things need in order to live and grow healthily.

Importance: 1. To get energy Gigi 2. To grow Ghazali 3. To build new cell Baru 4. To repair damaged tissue Rongak, 5. To maintain good health Mak…

Nutrient can be found in the 5 basic classes of food, there are:

Class of food Example Main ImportanceCarbohydrates Bread, Rice, Sugar Energy supplier

Proteins Meat, Fish, Egg “Fats Butter, Cheese, Oils “

Minerals & vitamins Vegetables, FruitsBody’s protection from

certain diseases Dietary fibre “ Constipation prevention

Water - Transportation of substances in bloodTo maintain body’s temperature (37ºC)

1.2 CALORIFIC VALUES IN FOOD

Definition: Amount of energy released by one gram of food when it is completely oxidized (digested)

How to measure: By using food calorimeter

NUTRITION

1. NUTRITION AND GOOD EATING HABITS

4. MANAGING FOOD RESOURCES

3. THE NITROGEN CYCLE

2. NUTRIENT REQUIREMENT PLANTS

Keyword

Unit: kilojoules per gram (kJ/gram) Different type of foods give different calorific values

FoodCalorific values

(kJ/g)Food

Calorific values (kJ/g)

Bread 10.6 Milk 2.7Butter 31.2 Mutton 10.1

How to calculate energy supplied by food?

Energy supplied = mass of food (in gram) * calorific values

Example :

1. Find energy supplied by:

1) 80 g of bread2) 150 g of butter3) 65 g of milk4) 500 g of mutton

2. Find the total energy supplied for these foods

1.3 FACTORS AFFECTING ENERGY INTAKE

Amount of energy required by person depend on:

1. Sex SheilaMale need more energy than female

2. Body size BasuhPerson who has big size need more energy than person who has small size

3. State of health StokinNormal person need more energy than sick person

4. Physical activities PutihPeople who do hard job need more energy than people who do easy job

5. Temperature of surroundings TimahPeople who live in cold country need more energy than people who live in other places

Keyword

1.4 BALANCED DIET

Definition: Diet which consists of all the classes of food, include water and dietary fibre, in the correct proportions.

Importance: 1. To get energy Gigi 2. To grow Ghazali 3. To build new cell Baru 4. To repair damaged tissue Rongak, 5. To maintain good health Mak…

1.5 HEALTH PROBLEM

A lot of problems might be arising from over eating, less eating or eating unbalanced diet. For example:a) Malnutrition (eating unbalanced diet) d) Diseases due to unhealthy eatingb) Obesity (more eating) habits (eating unbalanced diet).c) Anorexia nervosa (less eating)

For part a) malnutrition, diseases might be arising are as follow as:

Nutrient lacking

Disease Main symptoms Picture

Carbohydrate Marasmus Weak, dehydrated, severely underweight & shrunken appearance

Protein Kwashiorkor Loss of appetite, failure to grow & much swallowed abdomen

Iron Anaemia Pale appearance & loss appetite

Iodine Goitre Large swelling at the neck

Calcium Osteoporosis Weak bones and teeth & back bone might be bent

Keyword

Carbohydrates = 80%Proteins = 7.5%Fats = 10%Minerals & vitamins = sufficient amountDietary fibre = sufficient amountWater = 7-8 glasses

Vitamin A Night blindness

Poor eye sight at night

Vitamin B Beri-beri Weakness of the legs & lack of nervous sensation in the fingers and toes

Vitamin C Scurvy Bleeding gums

Vitamin D Rickets Bent legs due to the weak bones

Dietary fibre Constipation Difficulty in getting rid of solid waste from the body

For part b) obesity,

- It happens due to over eating for long period of time. So, the excess food is converted into fat and stored under skin (especially in the abdomen). As a result, person will become very fat or obese

- Diseases might be arising from obesity are:

a) high blood pressure d) stones in the gall bladderb) heart disease e) bent backbonec) diabetes

- How to avoid from being obese?

1. Control the way of eating 2. Do exercise regularly

For part c) anorexia nervosa,

- It happens due to insufficient amount of food taking by person especially ladies since they want to get slim body to look attractive. Eventually, they will vomit the digested food and as a result, they will become thin, dehydrated, and very undernourished.

- It also classified as social and psychological problem

- How to avoid from being “anorexia nervosa” person?

1. Take nutritious meal 2. See psychiatrist and therapist

For part d) diseases due to unhealthy eating habits,

- Diseases might be arising from these poor habits are:

1. hypertension 2. stroke - other name for high blood pressure - stroke occurs if artery of the brain bursts- affect to the heart - it can cause paralysis of part of the body - happens due to taking too much salt or the whole body

3. tooth decay 4. diabetes melitus- happen due to excess sugar in food, - happen when body can’t produce enough so bacteria inside the mouth change it insulin to deal with excess glucolin (cameinto lactic acid, and this acid destroy from food) the tooth’s enamel. - it can cause tiredness, coma, even worse- to avoid it, person should: deatha) eat less sugary food - to avoid it, person should: b) always brushing the teeth after eat a) eat less sugary food

b) do exercise regularly c) control weight

5. Atherosclerosis 6. Heart attack- happens due to excess of cholesterol - occur when the blood’s flow to the heart in bloodstream stop and part of the heart die.- it makes artery becomes hard, less elastic - it might be fataland resist blood’s flow

- to avoid it, person should:a) give up smokingb) control weightc) do exercise regularly

- side effect: hypertension d) eat healthy food

Importance of Taking Good Nutrition and Practicing Good Eating Habits

o Help us to prevent deficiency diseases such as ricket, goiter, scurvy and etc.o Help us to prevent health problem such as hypertension, stroke, diabetes and etc.o Supply necessary energy that required by uso Maintain our good health

Note:

Good eating habits that we should adopt include the following:

o Eat nutritious foodo Eat food which is rich in dietary fibreo Avoid taking food which has no nutritional valueo Avoid taking excessive amount of salts, sugars and fats with your foodo Drink 7-8 glasses of water per day

2 NUTRIENT REQUIREMENTS OF PLANTS

2.1 PHOTOSYNTHESIS IN GREEN PLANTS

Definition: Synthesize of food process by green plants in presence of sunlight using water (H2O) and carbon dioxide (CO2).

Water + Carbon Dioxide Glucose + Oxygen

How photosynthesis occur:

Importance of photosynthesis:

o Helps to maintain the balance of carbon dioxide and oxygen in atmosphereo Supply foods to green plants, animals and human being

sunlight

chlorophyll

Watero Absorbed

through the roots

o Transport along xylem to the leaves

Carbon dioxideo Absorbed

from air through the stomata in leaves

Glucoseo Combination

of hydrogen and carbon dioxide

Oxygeno Waste

producto Released

from leaves through stomata

Sunlighto Supply

energy for this process

Chlorophyllo Absorb

sunlight

2.2 MACRONUTRIENTS

Definition: Minerals required by plants in large amount for their healthy growth

Macronutrients and their functions:

Macronutrient FunctionCarbon (C) To form carbohydrates, proteins and fats

Hydrogen (H) “Oxygen (O) “Nitrogen (N) To form hormones, proteins, nucleic acid and chlorophyll

Phosphorus (P) To form proteins and nucleic acidTo stimulate the production of flowers and fruits

Potassium (K) To form carbohydrates, proteins and new cellsTo build up resistance for disease

Calcium (Ca) To form cell wallsFor growth

Magnesium (Mg) To form chlorophyllTo activate certain enzymes

Sulphur (S) To form certain amino acidsFor growth

2.3 MICRONUTRIENTS

Definition: Minerals required by plants in very small amount for their healthy growth. They also have known as trace elements.

Micronutrients and their functions:

Micronutrient FunctionBoron (B) To help in the breaking up of the carbohydrates

Molybdenum (Mo) To help nitrogen to carry out its functionsZinc (Zn) To activate certain enzymes

Manganese (Mn) “Copper (Cu) To form enzymes for photosynthesis

Iron (Fe) To form chlorophyll

Effects of Deficiency of Nitrogen, Phosphorus and Potassium on Plant Growth

Macronutrient Deficiency symptomNitrogen (N) Stunted (short) growth

Leaves are small, yellow and drop off easily Phosphorus (P) Poor growth especially the roots.

Few flower and fruitsPotassium (K) Leaves turn yellow (chlorosis)

Plants are weak and die before maturing.

3 NITROGEN CYCLE AND ITS IMPORTANCE.

3.1 NITROGEN CYCLE

3.2 IMPORTANCE OF NITROGEN CYCLE

o Maintain soil fertilityo Increasing production of cropso Maintaining the amount of nitrogen in atmosphereo Reducing pollution of the environment

Nitrogen in atmosphere

Nitrites Plant proteins

Nitrates Nitrates

Ammonium in compounds Animal proteins

Absorption

NutritionAction of nitrifying bacteria

Synthesis of nitrogen fixing bacteria

Lightning

Absorption

Decay by bacteria and fungi

Action of nitrifying bacteria

Action of denitrifying bacteria

Decay by bacteria and fungi

4 MANAGING FOOD RESOURCES AND HEALTHY EATING HABITS

- Plant and animals are said to be our food resources. Thus, we should manage these food resources so that there will be a continuous food supply for us.- To manage these food resources, we have to do a lot of following things: Avoid wastage Ensure that we do not cook more than we can eat.

- Besides, we have to practice healthy eating habits in our daily life. It can be done by: Eat well-balanced diet Avoid skipping meals especially breakfast Eat our food slowly so that the brain has enough time to register fullness. Avoid taking excessive amount of sugars, salts and fats in our food