IGCSE Co-ordinated sciences double awards

Respiration

Chemical reactions in cells that break down nutrient molecules and release energy for metabolism.

Diffusion

The net movement of particles from a region of higher concentration to a region of lower concentration down a concentration gradient as a result of their random movement.

Osmosis

The net movement of water molecules from a region of higher water potential to a region of lower water potential through a partially permeable membrane.

Active transport

The movement of particles through a cell membrane from a region of lower concentration to a region of higher concentration against a concentration gradient using energy from respiration.

Photosynthesis balanced symbol equation

$$6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2$$

Aerobic respiration balanced symbol equation

$$C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O$$

Magnification formula

$$\frac{\text{image size}}{\text{actual size}}$$

Avogadro constant

$$6.02 \times 10^{23}\,mol^{-1}$$

Isotopes

Atoms of the same element that have the same number of protons but different numbers of neutrons.

Exothermic reaction

A chemical reaction that transfers thermal energy to the surroundings, leading to an increase in the temperature of the surroundings.

Endothermic reaction

A chemical reaction that takes in thermal energy from the surroundings, leading to a decrease in the temperature of the surroundings.

Retention factor ($R_f$) formula

$$\frac{\text{distance travelled by substance}}{\text{distance travelled by solvent}}$$

Speed equation

$$v = \frac{s}{t}$$

Acceleration equation

$$a = \frac{\Delta v}{\Delta t}$$

Density formula

$$\rho = \frac{m}{V}$$

Gravitational field strength equation

$$g = \frac{W}{m}$$

Spring constant equation

$$k = \frac{F}{x}$$

Kinetic energy formula

$$E_k = \frac{1}{2}mv^2$$

Gravitational potential energy change formula

$$\Delta E_p = mg\Delta h$$

Wave speed equation

$$v = f\lambda$$

Snell's Law refractive index equation

$$n = \frac{\sin(i)}{\sin(r)}$$

Ohm's law resistance formula

$$R = \frac{V}{I}$$

Electrical power equation

$$P = IV$$

Electrical energy equation

$$E = IVt$$

Transformer turns and voltage ratio formula

$$\frac{V_p}{V_s} = \frac{N_p}{N_s}$$

100% efficient transformer power equation

$$I_p V_p = I_s V_s$$

Power loss in electrical cables equation

$$P = I^2 R$$

Orbital speed formula

$$v = \frac{2\pi r}{T}$$

Homeostasis

The maintenance of a constant internal environment.

Transpiration

The loss of water vapour from plant leaves, mainly through the stomata.