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...
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...
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 ...
Interphase Within multicellular organisms, not all cells retain the ability to divide Eukaryotic cells that do retain the ability to divide show a cell cycle Mitosis is part of a precisely controll...
The Principles & Limitations of Microscopy Microscopes can be used to analyse cell components and observe organelles Magnification and resolution are two scientific terms that are very importan...
The Cell Theory Until microscopes became powerful enough to view individual cells, no-one knew for certain what living organisms were made from A scientist called Robert Hooke is thought to be the ...
The Structure of ATP All organisms require a constant supply of energy to maintain their cells and stay alive This energy is required: In anabolic reactions – building larger molecules from ...
