What are the shoelaces in the eggs in the biology book?

The yolk frenulum is composed of thick protein at both ends of the yolk, which keeps the egg cells in the center of the protein, plays a buffering role, prevents the egg from shaking, and is beneficial to the hatching of the egg.

Eggs, also called chicken eggs and eggs, are laid by hens. There is a hard shell outside, and there are air chambers, egg whites and yolk inside. Rich in cholesterol and nutrition, an egg weighs about 50 grams and contains 7 grams of protein. The amino acid ratio of egg protein is very suitable for human physiological needs, easy to be absorbed by human body, with a utilization rate of over 98% and high nutritional value, and it is one of the foods that human beings often eat. Eggs can be divided into three parts: eggshell, egg white and yolk.

The most nutritious cooking method: there are many ways to eat eggs. In terms of nutrient absorption and digestibility, boiled eggs are 100%, scrambled eggs are 97%, tender fried eggs are 98%, old fried eggs are 8 1. 1%, boiled eggs with milk are 92.5%, and raw eggs are 30% ~ 50%. From this point of view, boiled eggs are the best way to eat, but pay attention to chewing slowly, otherwise it will affect absorption and digestion. But for children, steamed egg soup and egg drop soup are the most suitable, because these two methods can loosen protein and be easily digested and absorbed by children.