Energy.

Question 1

Why is energy needed in the body?

Answer 1

Every function and process in the body requires a source of energy.

Question 2

All energy is initially supplied by food and is then what happens afterwards?

Answer 2

All energy is initially supplied by food, and released for use in the body after digestion and absorption.

Question 3

What are the four uses of energy in the body?

Answer 3

• Mechanical energy.
• Chemical energy.
• Heat energy.
• Electrical energy.

Question 4

Give an example of mechanical energy.

Answer 4

For the movement of muscles (voluntary and involuntary).

Question 5

Give an example of chemical energy.

Answer 5

For all chemical and metabolic reactions.

Question 6

Give an example of heat energy.

Answer 6

To maintain body temperature.

Question 7

Give an example of electrical energy.

Answer 7

For the transmission of nervous impulses.

Question 8

What are the three main nutrients that supply energy?

Answer 8

There are three primary nutrients that supply energy - protein, fat, and carbohydrates.

Question 9

Of the three main nutrients that supply energy, which one provide the most concentrated source of energy?

Answer 9

Of these three fat provides the most concentrated source of energy.

Question 10

Give examples of the most energy dense foods.

Answer 10

• Fats - lard, butter, margarine, suet.
• Oils - vegetable/plant, nut.
• Fatty foods - egg yolk, cheese, cream, bacon.
• Others - sugar, cereals, cereal products and starchy vegetables.

Question 11

Energy is released in a reaction between glucose and oxygen which takes place in all body cells. The reaction produces energy, CO2, and H2O as by-products.
Give the equation of this statement.

Answer 11

Glucose + Oxygen → energy + carbon dioxide + water.

Question 12

Glucose + Oxygen → energy + carbon dioxide + water. What does this reaction where energy is produced require?

Answer 12

This reaction where energy is produced requires B Vitamins; Phosphorus; and lodine.

Question 13

What happens during energy release?

Answer 13

• Glucose from food is digested and goes into the bloodstream.
• Oxygen is breathed into the lungs, then goes into the bloodstream, then attaches to the hemoglobin in red blood cells.
• Hemoglobin contains iron which is important to transport oxygen and energy release.

Question 14

Not all glucose is converted to energy. What

Answer 14

• Some are stored as GLYCOGEN in the liver and muscles (energy from glycogen can be released quickly e.g. to run a race).
• Some as fat in the adipose tissue under the skin (energy stored as fat is released slowly e.g. in times of famine).

Question 15

Energy is measured in kilocalories (kcal) or kilojoules (kj). How many kilojoules in one kilocalorie?

Answer 15

1kcal = 4.2kj.

Question 16

How many kilocalories and kilojoules in:
- 1 gram of protein.
- 1 gram of fat.
- 1 gram of carbohydrate.

Answer 16

• 1g of protein = 4kcal or 17kj.
• 1g of fat = 9kcal or 38 kj.
• 1g of carbohydrate = 3.75kcal or 16kj.

Question 17

The amount of energy used by the body is called energy expenditure. This varies widely according to the: 5 reasons.

Answer 17

• Age.
• Sex.
• Occupation.
• Physical activity.
• State of the body e.g. pregnancy, illness.

Question 18

Give one group which require more energy because of age and why?

Answer 18

Young children need more energy as they are growing rapidly and tend to be very active.

Question 19

Which gender requires more energy and why?

Answer 19

Men tend to be larger in body size so they have a higher
metabolism.

Question 20

Give examples and reasons of occupation that requires less energy and those that require more energy.

Answer 20

Office workers, pilots, and architects (sedentary) require less energy than manual workers, army workers, and athletes (moderately/very active) who require more energy.

Question 21

Give three states of the body that require more energy.

Answer 21

extra energy is required in pregnancy for the growth of the baby, lactating mothers require extra energy for the production of milk. Those that are ill require less energy as their metabolism may be decreased.

Question 22

At least half of the energy released in the body is used for basal metabolism (resting metabolism).
Define Basal Metabolic Rate (B.M.R).

Answer 22

This is the amount of energy that is required to keep the body alive when it is at complete rest and warm.

Question 23

What is the basal metabolism used for?

Answer 23

It is used to keep the heart, lungs, and digestive system moving.
The rest of the energy is used by the muscles and to maintain posture.

Question 24

In what case is excess energy stored in the body as fat?

Answer 24

If the energy intake of food exceeds the amount of energy required, then the excess is stored in the body as fat.
This is one of the major causes of obesity.

Question 25

Give examples of empty calories (little value to the body.

Answer 25

Foods such as chocolates, sweets, crisps, etc. are energy dense but they contain very little in the way of nutrients.

Question 26

Why must a person who wants to lose weight reduce their energy intake?

Answer 26

To lose weight, a person must reduce the energy intake from food, so that reserves of energy in body fat are used and weight is lost. An increase in physical activity also helps.

Question 27

What is energy balance?

Answer 27

Energy intake = Energy output.

Question 28

Fill in the missing spaces:
When the energy ____ exceeds the energy ____, there is positive _____. When the energy ____ exceeds the energy _____ balance, which results in _____ gain.

When the energy ____ is below the energy ____, there is a negative _____ balance and weight ____ results. So therefore a ____ is required to maintain a balance.

Answer 28

When the energy intake exceeds the energy output, there is positive energy. When the energy intake exceeds the energy output balance, which results in weight gain.

When the energy intake is below the energy output, there is a negative energy balance and weight loss results. So therefore a balance is required to maintain a balance.

Question 29

The energy values of some foods can be increased by adding fat. Why?

Answer 29

This is due to most foods absorbing a large amount of fat during frying.

FOR EXAMPLE, Fried egg has an energy value almost double that of a boiled egg.
- Butter to mashed potato also increases energy value.

Question 30

Why are fruits and vegetables suitable in weight reducing diets?

Answer 30

Fruits and vegetables contain a high proportion of water and are low in energy value so they are also useful in weight-reducing diets.

Question 31

Why is grilling chops, sausages and bacon better than frying?

Answer 31

Grilling chops, sausages, and bacon is better than frying as some of the fat in the food will drain away and decrease the energy value.

Question 32

What can be used to reduce the energy value in drink and dishes?

Answer 32

Low-energy products such as sugar substitutes can be used to reduce the energy value of drinks and dishes.