B6 NUTRITION

Question 1

Which three groups of food molecules do we need most in a healthy diet?

Answer 1

Carbohydrates
Proteins
Fats

Question 2

Give examples of foods that are good sources of each group of food molecules.

Answer 2

Carbohydrates from pasta, rice, potato, bread, wheat flour
Proteins from meats, pulses, milk products, nuts
Fats from vegetables oil, butter, full-fat milk products, red meat.

Question 3

Which other substances are needed in our diet.

Answer 3

Vitamins,
minerals,
water
fibre.

Question 4

Explain why different groups of people needed different amounts of nutrients. Give examples in your answer.

Answer 4

Different people needs different amount of energy every day.
For examples:
Active people need more energy than the people who are seated for much of the day.

Question 5

Explain why someone following a healthy diet needs to consider energy as well as nutrients.

Answer 5

Food that contains more energy than the body uses is converted into body fat, leading to obesity, which is associated with many health problems.
A diet that results too low in energy leads to health problem as a result of low body weight.

Question 6

Explain why Obesity are considered to be a result of malnutrition:

Answer 6

Obesity is caused by a diet that contains too much energy, and is associated with many diseases.

Question 7

Explain why starvation are considered to be a result of malnutrition:

Answer 7

Starvation is a diet too low in energy and/or nutrition, leading to health problem from deficiency diseases or breakdown of muscle tissue for energy.

Question 8

Explain why constipation are considered to be a result of malnutrition:

Answer 8

Constipation is caused by too little fibre in the diet and may lead to diseases such as bowel cancer and diverticulitis.

Question 9

Explain the difference between egestion and excretion.

Answer 9

Egestion is a removal of undigested food from the alimentary canal- food that has never crossed the intestine wall into the body.

Excretion is the removal of waste substances that have been produced inside the body.

Question 10

Explain how the muscles of the alimentary canal wall move food.

Answer 10

Peristalsis caused by contraction of the circular muscles of the alimentary canal, followed by relaxation as the longitudinal muscles contract.

Question 11

Explain the difference between chemical and mechanical / physical digestion.

Answer 11

Chemical digestion uses chemicals (enzymes) to help break down large food molecules into smaller ones.

Mechanical / physical digestion is the chewing by the teeth to break large pieces of food into smaller ones before swallowing, or the breaking up of large fat droplets into smaller ones by bile.

Question 12

Explain why enzymes are needed in the digestive system.

Answer 12

The digestive enzymes break down food molecules that are too large to cross the wall of the small intestine into smaller ones that can be absorbed across cell embraces and so enter the body.
If we do not have enzymes, we would not be able to absorb many nutrients from our food.

Question 13

Which enzyme has starch as its substrate?

Answer 13

Amylase

Question 14

Which product is formed by the digestion of starch by this enzyme?

Answer 14

Glucose

Question 15

Describe the role of stomach acid.

Answer 15

The acid increases stomach acidity, providing the right conditions for enzymes that digest food in the stomach.