Carbohydrate polymers, such as starch and cellulose, are complex molecules composed of repeating units of simple sugars, and play important roles in energy storage, cell wall structure, and other physiological processes in living organisms. Keep reading for more detailed A-level Biology revision! Summary Classification of Carbohydrates There are several ways to classify carbohydrates. Some of …
Collagen is a member of a family of naturally occurring proteins. It is one of the most plentiful proteins present in mammals and it is responsible for performing a variety of important biological functions. It is most well-known for the structural role it plays in the body. It is present in large quantities in connective tissue and provides tendons and ligaments with tensile strength and skin with elasticity. It often works in conjunction with other important proteins such as keratin and elastin.
The cell is the functional and building unit in all living organisms. These cells are characterized by their ability to grow, reproduce, respond to external stimuli and perform the different metabolic processes.
You know that the structure of living organisms comes in gradual levels. These levels begin with the systems, organs, tissues, cells and finally come the organelles. If we follow up this structural sequence of living organisms, we will find that the cells of any living organism are made up of organic and inorganic molecules and each of these molecules is made up of atoms as well.
The circulatory system consists of the heart and the blood vessels through which the blood passes. These vessels form a complete circuit. (A closed circulatory system).
You know that the structure of living organisms comes in gradual levels. These levels begin with the systems, organs, tissues, cells and finally come the organelles. If we follow up this structural sequence of living organisms, we will find that the cells of any living organism are made up of organic and inorganic molecules and each of these molecules is made up of atoms as well.
The heart is a hollow muscular organ which lies in the middle of the chest cavity. It is enclosed in the pericardium that protects the heart and facilitates its pumping action. It is divided into four chambers.
By the early 1950’s there was strong evidence that DNA carries a cell’s genetic information of the cell and many people were trying to work out the structure of the DNA molecule and make a model of it.
Most living organisms are composed of several cells. But, are these cells irregular or disordered? Does each of them work separately from the other?
The enormous variety of proteins in living systems can be divided into two main groups: Structural proteins and Regulatory proteins.
