Key points of knowledge

1, nutritional function

Provide energy: Sugar, fat and protein can be oxidized and decomposed to provide energy.

The order of energy supply is sugar, fat and protein.

Protein is the main raw material for tissue construction and repair.

Provide construction and repair materials: sugars and lipids are important components of cell membranes and nerve tissues.

Gallium, magnesium, magnesium, phosphorus are the main components of bones.

Enzymes and some hormones are protein.

Iodine, a regulator, is the main component of thyroid hormone.

2. Malnutrition:

Insufficient supply in protein will affect development and resistance.

Insufficient nutrition supply and calcium deficiency affect bone development.

Lack of vitamin A can lead to night blindness.

Vitamin c deficiency can lead to scurvy.

Overnutrition: If you consume too much energy, it will lead to obesity.

The type, quantity and proportion of nutrient intake meet the actual needs.

Reasonably process food, reduce the loss of nutrients and improve the utilization rate.

3. Reasonable diet: food is non-toxic to human body and meets the requirements of food hygiene.

Establish good eating habits and a reasonable eating system.

Example understanding

Example 1. The following substances belong to the substances that the human body builds and repairs body tissues. One group is:

① Water ② Lipids ③ Sugar ④ protein Σ Cellulose Σ Inorganic salts Σ Vitamins.

a、①③④⑤⑦B、①③④⑥⑦C①②③④⑥D、①②③④⑥⑦

Analysis: The main substances involved in the construction and repair of human tissues are water, protein, lipids, sugars and inorganic salts. Cellulose is the main component of plant cell wall; Cellulose is an important substance to regulate the physiological function of the body. Answer: c

Example 2, the following are not reasons why adults should eat a certain amount of protein every day:

First, protein cannot be stored in the human body.

B, protein can't all be transformed from sugar and fat in the body.

C protein provides most of the energy needed for life activities.

D, every day to decompose a small amount of protein in the body, and add a new protein.

Analysis: protein is an indispensable and important substance for living things. Although it can be used as an energy substance, it is not the main one. The order of energy supply of substances in the body is sugar, fat and protein.

Answer: c

self-assessment

Multiple choice question:

1. The following statement about human nutrition is incorrect: ()

A, because protein can participate in various life activities, it is advisable to use the protein content in food every day.

B, it is not advisable to wash rice too often to prevent the loss of vitamin B 1.

C, vegetables should be washed first and then cut, and quickly fried with fire to prevent the loss of vitamin C.

D, food processing should not only prevent biological pollution, but also prevent chemical pollution caused by excessive preservatives.

2, can't appear in the human blood is ()

A, cellulose B, red blood cells C, protein D, hormones

3. Some people are bloated due to malnutrition, and their diet therapy is: ()

A, eat more vegetables B, eat more steamed bread C, drink more soy milk D, and drink more water.

4. 1g The energy released by sugar, fat and protein in the body is 17 respectively. 15 kJ，38。 9 1 kJ and 17. 15 kJ, from which we can draw the conclusion: ()

First, these three substances can be used as energy sources.

B, protein is the main energy substance.

Sugar is the main energy substance.

D. Fat is the main energy substance.

5. Which of the following diseases is caused by malnutrition: ()

A, beriberi and scurvy B, night blindness and gigantism

C. Diabetes and rickets

6. If a healthy person eats more sugar and salt, then the amount of glucose and salt in his urine: ()

A, salt has increased, but sugar has not increased. B, sugar has increased, but salt has not increased.

C, all increased by D, none increased.