Carbon dioxide and oxygen are two molecules that undergo this simple diffusion through the membrane.
A food is something that provides nutrients. Nutrients are substances that provide: energy for activity, growth, and all functions of the body such as breathing, digesting food, and keeping warm; materials for the growth and repair of the body, and for keeping the immune system healthy. (So we don’t die:))
Secondary structure of protein.
in seconday structure, the polypeptide chain is spirally arranged in linear form.
Teriary structure of protein
In tertiary structure the polypeptide chain is arranged in three dimension.
Quaternary structure of protein
In this structure more than one polypeptide chain are arranged in three dimension forming a globular shape.