Chapter Three - Nutrition and Health

Question 1

How are energy requirements calculated?

Answer 1

To determine how much energy a person needs, the Harris Benedict model calculates the Basal metsbolic rate (BMR) - the amount of energy required to maintain a constant body mass at rest. This takes into account your activity levels, size age and gender.

Question 2

Why do we control our energy intake?

Answer 2

If a persons diet provides more energy than they use during normal day-to-day activities then they will store any excess as fat. Over time this can lead to obesity.

Question 3

What is BMI? What is it used for?

Answer 3

Health professionals often use a persons body mass index (BMI) along with blood pressure readings to assess their general health. To calculate BMI divide the persons weight (kg) by the square of their height (m).

Question 4

What is recommended to maintain a healthy body?

Answer 4

All diets should contain plenty of fresh fruit and veg and keep the amounts of salty, sugary and fatty foods to a minimum. This is reflected by government health initiatives such as the ‘5 a day’ campaign. Consuming a healthy diet individuals stand a better chance of avoiding conditions such as obesity, stroke, heart disease, diabetes, arthritis and high blood pressure.

Question 5

Explain the need for the government to take action over current high levels of obesity

Answer 5

Higher levels of diet-related illnesses need more treatment and this is putting more pressure on the NHS and is costing the country more. May result in increased taxation

Question 6

Give equation & How to calculate energy content in food

Answer 6

Energy released / Joules = mass of water / g X rise in temperature/degrees Celsius X 4.2

To obtain this data to use in equation, foods can be burned under a known mass of water. Temperature of the water can be recorded before and after to calculate temperature change.

Question 7

Label diagram of measuring the energy content in food

Answer 7

• thermometer
• water
• mounted needle or forceps
• burning

Question 8

Food test for sugar

Answer 8

Benedict’s test

Method - add equal volume of benedicts solution; heat carefully in a water bath

Positive result - colour change from blue to brick red ( green or orange indicates small amount of sugar)

Question 9

Food test for starch

Answer 9

Starch test

Method - add iodine

Positive result - yellow/brown to blue/black

Question 10

Food test for protein

Answer 10

Biuret test

Method - add sodium hydroxide followed by a few drops of copper sulphate; shake

Positive result - light blue to purple/lilac

Question 11

Food test for fat

Answer 11

Ethanol test

Method - extract oil/fats in ethanol; add to an equal volume of cold water

Positive result - clear to forms white emulsion

Question 12

Food test for vitamin C

Answer 12

DCPIP test

Method - add drops of the food juice to DCPIP

Positive result - blue to pink to colourless

Question 13

What is a balanced diet

Answer 13

One that contributes the correct levels of each food group; carbs, proteins, fats, vitamins, minerals, water and fibre. If a diet contains too much or little of any the person will become malnourished.

Question 14

Food groups, why each aspect is needed, good sources and deficiencies or problems;
Carbohydrates

Answer 14

Carbohydrates
- all are composed of carbon, hydrogen and oxygen
Glucose - provides energy rapidly, sweets & chocolate

Lactose - /\, milk (incl Breast)

Cellulose - indigestible a bulk of fibre comp of cellulose, all plant material (cell walls)

Starch - slow release energy, bread&rice&pasta&potato, comp of Chains of glucose

Glycogen - energy storage in animal cells, all animal material esp red meat, most animals store lots in muscles and liver

Question 15

The amount of energy you need depends on;

Answer 15

• age
• gender
• level of activity
• in addition pregnant woman require more energy for development of their foetus

Question 16

Food groups, why each aspect is needed, good sources and deficiencies or problems;
Proteins, fats and vitamins

Answer 16

Proteins - growth and repair, meat&fish&egg, comp of carbon, hydrogen and oxygen

Fats - energy&insulation, butter&fried food, comp of carbon, hydrogen and oxygen

Vitamin C - maintains cell health (esp in walls of blood vessels), citrus fruits, scurvy or gum deterioration and teeth lost

Vitamin D - strong bones&teeth, fish oils&eggs&milk&made by pigments in skin when exposed to sun, rickets - bones soften& can bow under weight

Question 17

Food groups, why each aspect is needed, good sources and deficiencies or problems;
Minerals, water & fibre

Answer 17

Iron - part of haemoglobin molecule in red blood cells needed to transport blood, red meat&green veg, anemia

Calcium - strong bones&teeth, muscle contraction and clotting, milk, cheese & veg, osteoporosis (brittle bones) in later life

Water - all reaction take place in solution - transport, fluid in joints &cytoplasm, all drinks, fresh fruit&veg, dehydration, leads to loss of cell function

Fibre - prevents constipation&maintain healthy digestive system, whole meal bread, fresh fruit&veg,cereals, most fibre is cellulose in plant cell walls