Mass Transport The need for a circulatory system The cells of all living organisms need a constant supply of reactants for metabolism, e.g. oxygen and glucose Single celled organisms can gain oxyge...
The Process of Digestion Digestion is a process in which relatively large, insoluble biological molecules in food (such as starch, proteins) are hydrolysed into smaller, soluble molecules that can ...
The Human Gas Exchange System: Structure Gas exchange takes place in the human thorax. This is a collection of organs and tissues in the chest cavity The main structures of the human gas exc...
Edexcel IGCSE Maths复习笔记 1.5.2 Surds - Rationalising Denominators What is a surd? A surd is the square root of a non-square integer How do we rationalise the denominator of a surd? Worked Exampl...
Surface Area to Volume Ratio Surface area and volume are both very important factors in the exchange of materials in organisms The surface area refers to the total area of the organism that is expo...
Edexcel IGCSE Maths复习笔记 1.5.1 Surds - Basics What is a surd? A surd is the square root of a non-square integer What can we do with surds? 1. Multiplying surds – you can multiply numbers under s...
Vaccines A vaccine is a suspension of antigens that are intentionally put into the body to induce artificial active immunity. A specific immune response where antibodies are released by plasma cell...
Cell Recognition Our bodies have several defence mechanisms against pathogens. These include: Preventing the entry of pathogens by a variety of physical and chemical defences, such as the skin, muc...
The Fluid Mosaic Model of Membranes Membranes are vital structures found in all cells The cell surface membrane creates an enclosed space separating the internal cell environment from the external ...
