Active Transport Active transport is the movement of molecules and ions through a cell membrane from a region of lower concentration to a region of higher concentration Active transport requires en...
Diffusion & Facilitated Diffusion Diffusion is a type of transport that can occur across a cell membrane Note that diffusion can also happen within a cellular compartment; the presence of a mem...
Practical: Investigating Membrane Structure & Permeability The permeability of cell membranes is affected by several factors such as Temperature pH The effect of such factors on membrane struct...
Cell 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 environment, and intr...
The Mammalian Lung: Structure & Function The lungs of air-breathing animals provide an ideal exchange surface for the diffusion of gases The lungs are located in the thorax, or chest cavity Som...
Fick's Law of Diffusion Fick's Law relates the rate of diffusion to the concentration gradient, the diffusion distance and the surface area This relationship can be represented by the following equ...
Properties of Gas Exchange Surfaces All organisms need to exchange gases with their environment, e.g. Aerobic respiration requires oxygen and produces carbon dioxide as a waste product Photosynthes...
1.2.11 Practical: Vitamin C Content Vitamin C is found in green vegetables, fruits, and potatoes It is essential for a healthy diet The chemical name for vitamin C is ascorbic acid Ascorbic acid is...
Lipids & CVD A risk factor is any factor that increases the chance of developing a particular condition or disease An increase in a risk factor does not guarantee the development of disease, bu...
