Biology definitions
1. movement: an action by an organism causing a change of position or place.
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2. respiration: the chemical reactions in cells that break down nutrient
molecules and release energy.
3. Sensitivity : the ability to detect and respond to changes in the environment .
4. growth: a permanent increase in size.
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5. reproduction: the processes that make more of the same kind of organism.
6. excretion:removal from organisms of toxic materials and substances in
excess of requirements.
7. nutrition: taking in materials for energy, growth and development.
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8. diffusion:the net movement of particles from a region of their higher
concentration to a region of their lower concentration down a concentration
gradient, as a result of their random movement.
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9. osmosis: the net movement of water molecules from a region of higher water
potential (dilute solution) to a region of lower water potential (concentrated
solution), through a partially permeable membrane.
10. enzymes: proteins that function as biological catalysts.
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11. photosynthesis: the process by which plants manufacture carbohydrates
from raw materials using energy from light.
12. balanced diet: ingestion of nutrients with correct proportions in order to avoid
malnutrition.
13. ingestion:the taking of substances, e.g. food and drink, into the body through
the mouth.
14. digestion: the breakdown of large, insoluble food molecules into small, water
soluble molecules using mechanical and chemical processes.
15. mechanical digestion: the breakdown of food into smaller pieces without
chemical change to the food molecules.
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16. chemical digestion: the breakdown of large, insoluble molecules into small,
soluble molecules.
17. absorption: the movement of small food molecules and ions through the wall
of the intestine into the blood.
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18. egestion: the passing out of food that has not been digested or absorbed, as
faeces, through the anus.
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19. transpiration: loss of water vapour from plant leaves by evaporation of water
at the surfaces of the mesophyll cells followed by diffusion of water vapour
through the stomata.
20. double circulation: blood flow in the heart twice in one complete cycle, once
to the lungs and the second to all body parts.
21. coronary heart disease: the blockage of coronary arteries and state the
possible risk factors as diet, stress, smoking.
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22. aerobic respiration: the chemical reactions in cells that use oxygen to break
down nutrient molecules to release energy.
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23. hormone: a chemical substance, produced by a gland, carried by the blood,
which alters the activity of one or more specific target organs.
24. gravitropism: a response in which parts of a plant grow towards or away
from gravity.
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25. phototropism: a response in which parts of a plant grow towards or away
from the direction from which light is coming.
26. asexual reproduction: a process resulting in the production of genetically
identical offspring from one parent.
27. sexual reproduction: a process involving the fusion of the nuclei of two
gametes (sex cells) to form a zygote and the production of offspring that are
genetically different from each other.
28. pollination: the transfer of pollen grains from the anther to the stigma.
29. fertilisation: the fusion of the nuclei from a male gamete (sperm) and a
female gamete (egg cell/ovum).
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30. food chain: showing the transfer of energy from one organism to the next,
beginning with a producer.
31. food web: a network of interconnected food chains.
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32. Producer: an organism that makes its own organic nutrients, usually using
energy from sunlight, through photosynthesis.
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33. Consumer: an organism that gets its energy by feeding on other organisms.
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34. herbivore: an animal that gets its energy by eating plants.
35. carnivore: an animal that gets its energy by eating other animals.
36. Decomposer: an organism that gets its energy from dead or waste organic
matter.
37. ecosystem: a unit containing all of the organisms and their environment,
interacting together, in a given area, e.g. a lake.
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38. trophic level: the position of an organism in a food chain or food web.
Chemistry definitions
1. Physical change: a change in the appearance of a substance but not
chemical properties.
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2. Chemical change: a change that affects chemical properties.
3. Element : substance that cannot be broken down into other substances.
4. Mixture: two or more elements mixed together physically but not chemically.
5. Compound: two or more elements mixed together chemically.
6. Solvent: a substance that dissolves the solute.
7. Solute: a substance that gets dissolved in the solvent.
8. Solution : a solute dissolved in a solvent.
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9. proton number (atomic number): the number of protons in the nucleus of an
atom.
10. nucleon number (mass number): the total number of protons and neutrons
in the nucleus of an atom.
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11. electrolysis: the breakdown of an ionic compound when molten or in
aqueous solution by the passage of electricity.
12. Exothermic: chemical reaction that gives out energy to the surrounding.
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13. Endothermic: chemical reaction that takes in energy from the surrounding.
14. oxidising agent : a substance which oxidises another substance during a
redox reaction.
15. reducing agent: a substance which reduces another substance during a
redox reaction.
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16. homologous series: families of compounds with the same general formula
and similar chemical properties.
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17. alkanes: saturated hydrocarbons whose molecules contain only single
covalent bonds.
18. alkenes: unsaturated hydrocarbons whose molecules contain one double
covalent bond.
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19. Cracking: reaction that produces alkenes.
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Physics equation definitions
2. Weight: is the gravitational force that is acting on a body.
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1. Mass : Mass is a measure of the amount of matter in an object.
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3. Density: is the amount of material in unit volume Or it is the mass per unit
volume.
4. Scalar : physical quantity described by magnitude only.
5. Vector : physical quantity described by magnitude and direction.
6. Acceleration : it is the rate of change of velocity with time.
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7. Force: It is the external factor affecting the body and changes its Speed or
Direction or Shape of the body.
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8. Hooke's law: Force is directly proportional to extension before limit of
proportionality.
9. Pressure: is force per unit area that one object.
10. Work : A force is doing work when it moves a body from a place to another a
certain distance.
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11. Power : rate of doing work.
12. Energy: is the ability to do work.
13. Law Of energy of Conservation: Energy is neither created nor destroyed
From one form to another ,but it can change.
14. Nuclear fusion : Physical processes that produce energy from the sun by
joining 2 or more lighter atoms into a large one.
15. Nuclear fission : Physical processes that produce energy from Nuclear by
splitting a large atom into 2 or more smaller ones.
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16. Evaporation: Is the change from liquid into a gas at any temperature below
the boiling point
17. Boiling point : it is the point when liquid turn to gas.
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18. Conduction : Is the Transfer of heat through matter from places of higher
temperature to places of lower temperature without movement of the matter
as a whole.
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19. Convection : Is the Transfer of heat through a fluid from places of higher
temperature to places of lower temperature by movement of the fluid itself.
20. Conductors: Materials which contain free electrons that flow through them
21. Insulators: Materials which contain no free electrons that flow through them.
22. Electric field : It is the region in space in which an electric charge effect
appears as lines of electric field.
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23. Voltage : is the amount of energy given to each coulomb passing through the
supply.
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24. Transverse waves : where air molecules vibrate perpendicular to the
direction of the wave propagation and consist of crests and troughs.
25. Longitudinal waves : is a series of compressions and rarefactions where air
molecules vibrate parallel to the direction of the wave propagation.
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26. Compression is sound waves : is the region where air molecules are close
to each other (the high pressure region).
27. Rarefaction in sound waves: is the region where air molecules are far apart
from each other (the low pressure region.
28. Wave Length ( λ) For transverse waves : Distance between two successive
crests or troughs.
29. Wave Length ( λ) For longitudinal waves :Distance between two
successive centres of compressions or rarefactions
30. Amplitude: It is the maximum displacement of particles about its original
position.
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31. Frequency : Number of complete waves in 1 second -Unit is (HERTZ) HZ
32. Angle of incidence : (i) is the angle between incident ray and normal
33. Angle of reflection : (r) is the angle between reflected ray and normal.
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34. Dispersion: is the separation of white light into its component colours by
using a prism to form a spectrum .
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35. A continuous spectrum : it contains different colours (light waves) where
the wavelength continuously changing from one colour to another .
36. A monochromatic light: it contains only one colour with one definite
frequency and wavelength.
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Rules
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Weight = mass × Acceleration due to Gravity
Force = mass x acceleration
Hooke's law : Force (in newton)= Spring constant(N/m) x Extension (m)
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Kinetic energy = ½ mass x velocity
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Gravitational Potential Energy (J) = Mass (kg) x Gravity (m/s2 ) x Height (m)
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Power (W) = Work done (J) / Time Taken (s)
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Voltage = Current X Resistance
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Current = Voltage / Resistance
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Resistance = Voltage / Current
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Charge (C(Coulombs)) = Current (A(Amps)) x Time (s(Seconds))
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Parallel connection
Rt = R1 + R2
Rt = product / sum = (R1 . R2 ) / (R1 + R2 )
Vt = V1 + V2
Vt = V1 = V2
It = I1 = I2
I t = I1 + I2
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Series connection
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