Fish, meat, eggs, milk, beans

For example, hemoglobin in the blood acts as a carrier in the process of inhaling oxygen and exhaling carbon dioxide.

Hemoglobin is made up of protein and heme.

In the lungs, Fe2 of heme in hemoglobin combines with oxygen to form oxyhemoglobin, which flows with the blood to various tissues and organs of the body, releasing oxygen for oxidation in the body. At the same time, hemoglobin combines with carbon dioxide in the blood and carries it to the lungs for exhalation.

Hemoglobin can also combine with carbon monoxide, and the binding ability is very strong, about 200 to 300 times that of oxygen. Once combined, it is not easy to separate, and it can no longer combine with oxygen, and people will die of hypoxia and suffocation. ——Causes of gas poisoning

Cigarette smoke contains hundreds of harmful substances to the human body

The most toxic ones are carbon monoxide, nicotine (nicotine), and tar containing carcinogens [benzopyrene (bǐ), dioxin (è) Ying, etc.].

People who smoke for a long time are susceptible to coronary heart disease, emphysema, lung cancer and other diseases. Heavy smoking can cause death from poisoning.

Some substances such as formaldehyde will react with proteins, destroy the structure of proteins, and cause them to deteriorate. This formaldehyde is seriously harmful to human health.

Soaking animal specimens in formaldehyde aqueous solution (formalin) enables the specimens to be preserved for a long time.

Specificity, diversity, efficiency

Enzymes are biological catalysts that can catalyze reactions in living organisms. An enzyme can only catalyze one type of reaction or type of reaction, and And it is generally carried out under body temperature and near neutral conditions.

When you chew rice and steamed buns in your mouth, you feel a sweet taste. This is because saliva contains amylase, which can hydrolyze part of the starch in the food into maltose; the remaining starch is hydrolyzed into maltose by pancreatic amylase in the small intestine; Maltose is hydrolyzed into glucose that can be absorbed by the human body under the catalysis of maltase in the intestinal juice. Most enzymes such as amylase and maltase are proteins.

Mainly found in plant seed starch or tubers

The chemical formula of starch is (C6H10O5)n. With different n values, the relative molecular mass ranges from tens of thousands to hundreds of thousands.

Food starch undergoes a series of reactions with water through the catalysis of enzymes in the human body, and eventually turns into glucose.

Glucose is absorbed through the intestinal wall and enters the bloodstream to become blood sugar, which provides nutrients to human tissues.

Glucose is slowly oxidized into carbon dioxide and water under the catalysis of enzymes, and at the same time releases energy to meet the needs of body activities and maintaining a constant body temperature.

C6H12O6 6O2 = enzyme = 6CO2 6H2O

main food

Is a commonly used sweetener in food

Cellulose is the building block of plant cells

Cotton contains more than 90% cellulose. Cellulose can be digested and absorbed by cattle, sheep, horses and other animals, but cannot be digested by the human body, but it plays a special role in the human body's digestion process.

You should ensure that you consume a certain amount of vegetables, fruits, whole grains and other fiber-rich foods every day.

Peanut oil, soybean oil, rapeseed oil, butter and cream, etc.

Lack of vitamin A can cause night blindness

Lack of vitamin C can cause scurvy

Lack of vitamin D can cause rickets

Vegetables, fruits, seed foods, animal livers, eggs, milk, fish, cod liver oil, etc.

Rice, peanuts, flour, corn, dried potatoes and beans should be stored in a dry and ventilated place, because they are prone to mildew and aflatoxin when the temperature is 30~38°C and the relative humidity exceeds 80%. of Aspergillus flavus.

Aflatoxin is very heat-resistant and cannot be destroyed by cooking. It can only be destroyed by heating to above 280°C.

Aflatoxins can damage the human liver and induce diseases such as liver cancer. Therefore, moldy food must not be eaten.