Compromises between Gas Exchange & Water Loss The exchange of gases from the atmosphere is essential for the survival of organisms Oxygen is required for respiration Carbon dioxide is re...
Adaptations of Gas Exchange Surfaces Effective exchange surfaces in organisms have: A large surface area Short diffusion distance Concentration gradient (maintained) Across the Body S...
The Relationship between Surface Area: Volume Ratio & Metabolic Rate The metabolic rate of an organism is the amount of energy expended by that organism within a given period of time The...
Edexcel IGCSE Maths 復(fù)習(xí)筆記 2.14.1 Quadratic Formula What is a quadratic equation? A quadratic equation looks like (or can/should be made to look like) this:ax2?+ bx + c = 0 (as long as a ≠ 0) &nb...
Adaptations In Large Organisms to Facilitate Exchange Single-celled organisms have a high SA:V ratio which allows for the exchange of substances to occur via simple diffusion The large surfa...
Practical Skill: Agar Blocks The effect of changing surface area to volume ratio on diffusion can be investigated by timing the diffusion of ions through cubes of agar of different sizes Met...
Edexcel IGCSE Maths 復(fù)習(xí)筆記 2.13.1 Linear Simultaneous Equations What are linear simultaneous equations? When there are two unknowns (say x?and?y) in a problem, we need two equations to be able to...
ELISA Each clone of plasma cells produces only?one type?of antibody These are known as?monoclonal antibodies Monoclonal antibodies can be used in?medical diagnoses They can be used in...
Edexcel IGCSE Maths 復(fù)習(xí)筆記 2.12.1 Direct & Inverse Proportion What is proportion? Proportion?is a way of talking about how two?variables?are related to each other Direct?proportion: as one va...
