Using DNA in science and technology

A cycle is a biological pathway or process in which the end product of one cycle becomes the starting point for the next cycle. Write an essay about cycles in biology. Carbon dioxide may affect organisms directly or indirectly. Describe and explain these effects. The causes of disease in humans. Mean temperatures are rising in many parts of the world. The rising temperatures may result in physiological and ecological effects on living organisms. Describe and explain these effects. The causes of variation and its biological importance. The transfer of substances containing carbon between organisms and between organisms and the environment. Movement in cells. Transfer through ecosystems. The part played by the movement of substances across cell membranes in the functioning of different organs and organ systems. The part played by enzymes in the functioning of different cells, tissues and organs. The ways in which organisms use ATP. The causes of genetic variation. Chemical coordination in animals and plants. The roles of proteins in living organisms.

The structure of enzymes and their uses in commercial processes. Digestion and absorption of carbohydrates and the regulation of blood glucose. The structures and functions of different types of plant cells. Polymers have different structures. They also have different functions. Describe how the structures of different polymers are related to their functions. Heat and many different substances are transferred within the human body and between the body and the environment. Explain how surface area is linked to this transfer. Carbon dioxide in organisms and ecosystems. How nitrogen-containing substances are made available to and are used by living organisms. The biological importance of plants to humans. How the structure of proteins relates to their function. Negative feedback and its importance in Biology. Factors which influence the concentration of glucose in the blood. Maintaining constant conditions in the body. Describe how ions including (sodium, phosphorus and hydrogen) are used in living organisms.