3 - PLANT NUTRITION AND TRANSPORT 

Minerals for healthy growth 

Deficiencies - 

1 - Nitrates 

• Contain nitrogen for making amino acids and proteins 
• Needed for cell growth 
• Stunted 
• Yellow older leaves 

2 - Phosphates 

• Contain phosphorus for making DNA and cell membranes 
• Needed for respiration and growth 
• Poor root growth 
• Purple older leaves 

3 - Potassium 

• Helps enzymes needed for photosynthesis and respiration 
• Poor flower and fruit growth 
• Discoloured leaves 

4 - Magnesium (small amounts) 

• Needed for making chlorophyll 
• Yellow leaves 

3 - PLANT NUTRITION AND TRANSPORT 

Photosynthesis 

• Produces food for plant (glucose) 
• Happens in the leaves of all green plants 
• Happens inside chloroplasts - in leaf cells and other green parts of plant, contain green pigment (chlorophyll) 
• Chlorophyll - green pigment, absorb sunlight, uses its energy to convert carbon dioxide and water into glucose (oxygen also produced - waste product) 
• Converts light energy to chemical energy (stored in the glucose) 
• Chemical energy released when glucose is broken down during respiration 

Leaves - 

•  Broad - large surface area exposed to light 
• Most chloroplasts found in palisade layer - near top of leaf, more exposure to light 
• Upper epidermis - transparent, light can pass through it to palisade layer 
• Network of vascular bundles - xylem and phloem (transport vessels), deliver water and nutrients, take away glucose produced, support leaf structure 

• Waxy cuticle - reduces water loss by evaporation 
• Adaptions of leaves for efficient gas exchange also make photosynthesis more efficient (eg: lower surface full of small holes - stomata, let carbon dioxide diffuse directly into leaf) 

Rate of photosynthesis  

Limiting factor - 

• Depends on environmental conditions (eg: winter - low temp., night - light etc.) 
• Stop photosynthesis from happening any faster 
• Light intensity, CO2, concentration, temperature 

Limiting factor: light 

• Chlorophyll uses light energy to perform photosynthesis 
• Light intensity increased - rate of photosynthesis increases steadily (only up to a certain point - only limiting factors are then either CO2 levels or temp) 
• Not enough light = slows down rate 

Limiting factor: carbon dioxide 

• CO2 - raw material needed for photosynthesis (only about 0.04% of air, fairly scarce for plants) 
• Increases rate of photosynthesis up to a point 
• Graph flattens out - no longer the limiting facto 

Limiting factor: temperature 

• Affects enzymes involved 
• Temp increases - rate of photosynthesis increases up to a point 
• Too high - denatures enzymes 

Experiments 

Testing leaf for starch - 

• Put in boiling water with tweezers/forceps - stops any chemical reactions happening inside leaf 
• Put in boiling tube with ethanol 
• Heat in water bath - gets rid of any chlorophyll, leaf end up pale/white 
• Rinse leaf in cold water 
• Add a few drops of iodine solution
• Present = blue/black 

Showing whether photosynthesis is taking place (starch tests) - 

1 - Chlorophyll 

• Use variegated leaves - only green parts contain chlorophyll (eg: ivy leaves) 
• Take variegated leaf from plant that has been exposed to light 
• Record which bits are green etc. 
• Test leaf for starch (previous experiment) 
• Present = blue/black (will only occur in green parts of leaf) 
• Only parts of the leaf that contained chlorophyll are able to photosynthesise and produce starch 

2 - CO2 

• Set up plant and dish of soda lime in bell jar (sealed) 
• Light shining through bell jar 
• Soda lime will absorb CO2 out of the air in the jar 
• Test leaf for starch (with iodine solution) after set period of time = none present 
• No starch been made in the leaf, CO2 needed for photosynthesis 

3 - Light 

• Plant that has grown without any light 
• Cut leaf from plant - test for starch using iodine solution 
• Light needed for photosynthesis 

Showing rate of photosynthesis (oxygen production) - 

1 - Light 

• Canadian pondweed used to measure the effect of light intensity on the rate of photosynthesis - rate at which the pondweed produces oxygen corresponds to the rate at which photosynthesis is taking place 
• The faster the rate of oxygen production, the faster the rate of photosynthesis 

1. Source of white light placed at a specific distance from pondweed 

2. Leave to photosynthesise for set time 

3. Syringe draws up gas produced 

4. Record results 

5. Repeat with light at different distances 

• Can be altered to measure effect of temperature or CO2 on photosynthesis 
• eg: put in beaker of water, different concentrations of CO2 bubbled through 
• eg: changing temp of water 

2 - HUMAN NUTRITION 

Alimentary canal 

Mouth - 

- Salivary glands in the mouth produce amylase in saliva 

- Teeth break down food mechanically 

Oesophagus - 

- Muscular tube 

- Connects mouth and stomach 

Liver - 

- Produces bile 

Gall bladder - 

- Stores bile 

Stomach - 

- Pummels food with muscular walls 

- Produces pepsin (protease enzyme) 

- Produces HCl - kills bacteria, right pH for proteas enzyme (pH 2) 

Pancreas - 

- Produces protease, amylase, lipase 

- Releases enzymes into small intestine 

Small intestine -

- Produces protease, amylase, lipase 

- Nutrients absorbed into body 

- Contains villi 

Large intestine - 

- Excess water absorbed by blood 

Peristalsis - 

• Muscular tissue all the way down alimentary canal 
• Squeeze boluses through gut 
• Squeezing action - waves of circular muscle contractions 

Digestive process - 

1. Ingestion 

• Putting food in mouth 

2. Digestion 

• Break-down of large, insoluble molecules to small, soluble molecules 
• Mechanical - teeth and stomach muscles 
• Chemical - enzymes and bile 

3. Absorption 

• Process of moving molecules through the walls of the intestines into the blood 
• Digested food molecules absorbed in small intestine 
• Water mainly absorbed in large intestine 

4. Assimilation 

• Digested molecules have been absorbed, moved into body cells - become part of cells (assimilation) 
• eg: amino acids used by cells to make cellular proteins 

5. Egestion 

• Undigested materials form faeces 
• Egested 

Villi (small intestines) - 

• Small intestine - adapted for absorption of food 
• Very long - time to break down and absorb all food 
• Large surface area for absorption - covered in millions of villi 
• Each cell on surface of villi has microvilli - increase surface area further 
• Villi - single permeable layer of surface cells, very good blood supple for quick absorption 

2 - HUMAN NUTRITION 

Digestive enzymes 

• Break down big molecules into smaller ones 
• Starch, proteins and fats are too big to pass through walls of digestive system and insoluble 
• Sugars, amino acids, glycerol and fatty acids are smaller, soluble and can pass through walls of digestive system 

Amylase - starch to maltose 

Maltase - maltose to glucose 

Protease(s) - proteins to amino acids 

Lipase(s) - lipids to glycerol and fatty acids 

Bile - 

• Produced in liver, stored in gall bladder, released into small intestine 
• Neutralises stomach acid 
• Emulsifies fats 
• HCl in stomach makes pH too acidic for enzymes in small intestine - bile neutralises/makes conditions alkaline 
• Emulsifies fats - breaks fats into tiny droplets (bigger surface area for lipase to break down - speeds up digestion) 

2 - HUMAN NUTRITION 

Balanced diet 

• Gives all essential nutrients in right proportions 
• Carbohydrates, proteins, lipids, vitamins, minerals, water 
• Fibre

Carbohydrates - 

• Pasta, rice, sugar 
• Provide energy 

Lipids (fats and oils) - 

• Butter, oily fish 
• Provide energy 
• Act as energy store 
• Provide insulation 

Proteins - 

• Meat, fish 
• Growth and repair of tissue 
• Provides energy in emergencies 

Vitamins -

1 - Vitamin A 

• Liver 
• Improves vision 
• Keeps skin and hair healthy 

2 - Vitamin C  

• Oranges 
• Prevents scurvy 

3 - Vitamin D 

• Eggs 
• Calcium absorption 

Mineral ions - 

1 - Calcium 

• Milk, cheese 
• Makes bones and teeth 

2 - Iron 

• Red meat 
• Makes haemoglobin 
• Healthy blood 

Water - 

• Food, drink 
• Most bodily functions 
• Homeostasis 
• Replaces water lost through urinating, breathing and sweating etc 

Dietary fibre - 

• Wholemeal bread 
• Movement of food through gut 

Energy requirements - 

• Activity level - active people need more energy 
• Age - children/teenagers need more energy than older people - growth, generally more active 
• Pregnancy - pregnant women need more energy - provide energy baby needs for development 

2 - HUMAN NUTRITION 

Biological molecules 

Carbohydrates - 

• Made up of simple sugars 
• Contain carbon, hydrogen and oxygen 
• Starch and glycogen are large, complex carbohydrates - made up of many smaller units (eg: glucose or maltose molecules) joined in a long chain 

Proteins - 

• Made up of long chains of amino acids 
• Contain carbon, nitrogen, hydrogen and oxygen 

Lipids - 

• Fats and oils 
• Made up of fatty acids and glycerol 
• Contain carbon, hydrogen and oxygen 

Testing for glucose (Benedict's reagent) - 

• Add Benedict's reagent (blue) to a sample (an excess) 
• Heat - do not boil 
• Positive = coloured precipitate (blue-green-yellow-orange-brick red) 
• The higher the concentration, the further the colour change goes - can compare 

Testing for starch (iodine test) - 

• Add iodine solution (iodine dissolved in potassium iodide solution - brown/orange) 
• Present = blue/black 
• No starch = stays brown/orange 

2 - ELECTRICITY 

Circuits

1 - Current

• the rate of flow of charge round the circuit 
• will only flow through a component if there is a voltage across that component 
• unit = amp, A

2 - Voltage

• driving force that pushes the current round 
• 'electrical pressure' 
• unit = volt, V 

3 - Resistance

• anything in the circuit that slows down the flow
• if you add more components to the circuit, there will be a higher overall resistance 
• units = ohm, Ω 

4 - Balance 

• voltage is trying to push the current around the circuit 
• resistance is opposing voltage 
• relative sizes of voltage and resistance decide how big the current will be 

INCREASE VOLTAGE = MORE CURRENT FLOWS 
INCREASE RESISTANCE =  LESS CURRENT FLOWS 

Standard test circuit - 

• Basic circuit used for testing components and getting V-I graphs 
• Component, ammeter and variable resistor all in series (can be put in any order in main circuit) 
• Voltmeter only placed in parallel around component being tested 
• Varying variable resistor alters current flowing - can take several pairs of readings from ammeter and voltmeter 
• Plot current and voltage on V-I graph

1 - Ammeter 

• Measures current (amps) flowing through the component 
• Must be placed in series 
• Anywhere in main circuit, never in parallel 

2 - Voltmeter 

•  Measures voltage (volts) across component 
• Must be placed in parallel 
• Around the component 

Mains supply/battery supply - 

• a.c. (alternating current - constantly changing direction) = mains 
• d.c. (direct current - current keeps flowing in same direction) = battery 
• UK - mains electricity = 230 volts 

Series circuits -

• Different components connected in a continuous line 
• Can't control which components current flows through - flows through all or none 
• If one component is removed/broken, the circuit is broken 
• eg: fairy lights 
• Same current flows through all parts of the circuit 
• A1 = A2 
• Size of current determined by total voltage of the cells and total resistance of circuit (I = V/R)
• Total resistance depends on the number of components and the type of components 

Parallel circuits -

• Each component is separately connected 
• If one component is removed/disconnected, hardly affects others 
• Diagram - each component in its own loop 
• How most things are connected (eg: household electrics - lights) 

Exceptions to series and parallel -

• Ammeters always connected in series 
• Voltmeters always connected in parallel with a component 

LEDs (light emitting diodes) -

• Emit light when a current flows through them in a forward direction 
• Numbers on digital clocks, traffic lights, remote controls 
• Don't have a filament that can burn out 
• Indicate the presence of current in a circuit - often used in appliances to show when they are switched on 

LDRs (light dependant resistors) -

• Type of resistor that changes its resistance based on how much light falls on it 
• Bright light - resistance falls 
• Darkness - resistance is highest 
• Electronic circuits (eg: burglar detectors) 

Thermistors -

• Temperature-dependant resistor 
• Hot - resistance drops
• Cool - resistance increases
• Temperature detectors (eg: car engine temperature sensors) 

Resistance 

VOLTAGE = CURRENT X RESISTANCE (V = I X R) 

Voltage/current graphs -

1 - Metal filament lamp

• As the temperature of the metal filament increases, the resistance increases 
• (x axis = V, y axis = I) 

2 - Wire

• Current through a wire (at a constant temp.) is proportional to voltage

3 - Diode

• Current will only flow through a diode in one direction 

4 - Different resistors

• The current through a resistor (at a constant temp.) is proportional to voltage 
• Different resistors have different resistances - different gradients

Charge, voltage, energy change 

• Current = rate of flow of electrical charge (A) 
• In solid metal conductors (eg: copper wire) charge is carried by negatively charged electrons 
• More charge passes around a circuit when  bigger current flows 
• (time must be in seconds - charge is measured in coulombs, C)

CHARGE = CURRENT X TIME

2 - ELECTRICITY 

Energy and power in circuits

Resistors -

• Produce heat when electric current passes through them 
• Energy transfer which heats the resistor 
• Heat increases the resistors resistance - less current will flow/greater voltage needed to produce same current
• Can cause components in circuit to melt - breaks circuit 
• Fuses use melting to protect circuits - melt and break the circuit if the current gets too high 
• Toasters contain coil of wire with very high resistance = heat
• Current passes through coil - temperature increases - glows and gives off infrared (heat) radiation 

Electrical power and fuse ratings -

• Electrical power - rate at which an appliance transfers energy 
• An appliance with a high power rating transfers a lot of energy in a short period of time
• Energy comes from current flowing through it 
• High power rating appliance - draws a large current from the supply 

Formula for electrical power =
ELECTRICAL POWER = CURRENT X VOLTAGE 

• Most appliances show their power rating and voltage rating 
• Fuses should be rated near but slightly higher than the normal operating current 
• Working out fuse needed - 

eg: a hair dryer is rated at 230V, 1kW - find the fuse needed

1kW = 1000W
I = P/V
  = 1000/230
  = 4.3A
Slightly higher = 5 amp fuse

Appliances transfer electrical energy -

• Current flows through component, energy is transferred 
• eg: lightbulb - electrical energy transferred into light energy and (waste) heat energy
• Energy transferred depends on the current through it, the voltage supplied and how lond (s) it is on for 

ENERGY TRANSFERRED = CURRENT X VOLTAGE X TIME 

RELIGION AND SOCIETY 

1 - Rights and responsibilities

The Bible as a basis for making moral decisions - 

• Moral decisions - where you have to decide what is the right or wrong thing to do 

Why many Christians use only the Bible -

• The Bible is the word of God - God's guidance to humans 
• Contains God's teachings on how Christians should behave (eg: The Decalogue - treatment of parents, stealing, murder, adultery etc.)
• Contains teachings of Jesus on how to live - Son of God 
• Contains letters from the leading disciples of Jesus on how Christians should behave - guided by Holy Spirit 

Why some Christians do not think the Bible is the most important guide for making moral decisions -

•  Think Bible was written by humans inspired by God - many attitudes need to be changed for modern world (eg: St Paul's attitude to women and slaves) 
• Need Church to tell them what the Bible means for today 
• Would use own conscience or reason to decide whether to follow the Bible today

RELIGION AND SOCIETY 

4 - Crime and punishment

Key words -
Addiction - a recurring compulsion to engage in an activity regardless of its bad effects
Capital punishment - the death penalty for a crime or offence
Crime - an act against the law
Deterrence - the idea that punishments should be of such a nature that they will put people off committing the crimes
Judgement - the act of judging people and their actions
Justice - due allocation of reward and punishment/the maintenance of what is right
Law - rules made by Parliament and enforceable by the courts
Reform - the idea that punishments should try to change criminals so that they will not commit crimes again
Rehabilitation - restore to normal life
Responsibility - being responsible for one's actions
Retribution - the idea that punishments should make criminals pay for what they have done wrong
Sin - an act against the will of God

RELIGION AND SOCIETY 

3 - Peace and conflict

Key words -
Aggression - attacking without being provoked
Bullying - intimidating/frightening people weaker than yourself
Conflict resolution - bringing a fight or struggle to a peaceful conclusion
Exploitation - taking advantage of a weaker group
Forgiveness - stopping blaming someone/pardoning them for what they have done wrong
Just war - a war which is fought for the right reasons and in a right way
Pacifism - the belief that all disputes should be settles by peaceful means
Reconciliation - bringing together people who were opposed to each other
Respect - treating a person or their feelings with consideration
The United Nations (UN) - an international body set up to promote world peace and cooperation
Weapons of mass destruction - weapons which can destroy large areas and numbers of people
World peace - the ending of war throughout the whole world (basic aim of UN)

RELIGION AND SOCIETY 

2 - Environmental and medical issues 

Key words -
Artificial insemination - injecting semen into the uterus by artificial means
Conservation - protecting and preserving natural resources and the environment
Creation - the act of creating the universe or the universe which has been created
Embryo - a fertilised egg in the first 8 weeks after conception
Environment -the surroundings in which plants and animals live and on which they depend to live
Global warming - the increase in the temperature of the Earth's atmosphere (caused by greenhouse effect)
Infertility - not being able to have children
In-vitro fertilisation - the method of fertilising a human egg in a test-tube
Natural resources - naturally occurring materials (eg: oil and fertile land) which can be used by humans
Organ donation - giving organs to be used in transplant surgery
Stewardship - looking after something so it can be passed onto the next generation
Surrogacy - an arrangement where a woman carries a child and gives birth on behalf of another woman

RELIGION AND SOCIETY

1 - Rights and responsibilities

Key words -
Bible - the holy book for Christians
Church - the community of Christians (non-capital C means a Christian place of worship)
Conscience - an inner feeling of the rightness or wrongness of an action
The Decalogue - the Ten Commandments
Democratic Processes - the ways in which all citizens can take part6 in government (usually through elections)
Electoral processes - the ways in which voting is organised
The Golden Rule - the teaching of Jesus that you should treat others as you would like them t treat you
Human rights - the rights and freedoms to which everyone is entitled
Political party - a group which tries to be elected into power on the basis of its policies
Pressure group - a group formed to influence government police on a particular issue
Situation ethics - the idea that Christians should base moral decisions on what is the most loving thing to do
Social change - the way in which society has changed and is changing (also possibilities for future change)

1 - PRINCIPLES OF CHEMISTRY 

Covalent bonding - 

• Shared pair of electrons 
• Both atoms have full outer shells 
• Each atom has to have enough covalent bonds to fill up outer shell 
• Strong attraction between the shared electrons and the nuclei of the atoms

eg: 
Hydrogen and chlorine = hydrogen chloride (HCl)
Ammonia (NH3)
Nitrogen (N2)
Water (H2O) 
Methane (CH4) 
Ethane (C2H6) 
Ethene (C2H4)

Simple molecular substances -

• Atoms within molecule held together by very strong covalent bonds 
• Forces of attraction between molecules are very weak - intermolecular forces
• Melting and boiling points are very low 
• Most are gases or liquids are room temperature 
• 'Mushy' physical state - liquid/gas/easily melted solid 

Giant covalent structures - 

• No charged ions 
• Atoms bonded to eachother by strong covalent bonds 
• Lots of energy to break the large amount of bonds 
• Very high melting and boiling points 
• Don't conduct electricity - no delocalised electrons 
• eg: diamond and graphite (carbon atoms) 

Diamond - 

• Each carbon atom forms 4 covalent bonds 
• Very rigid giant covalent structure 
• Hardest natural substance 

Graphite - 

• Each carbon atom forms 3 covalent bonds 
• Creates layers 
• Slide over each other 
• Good lubricant 
• Free electrons - only non-metal that is a good conductor
  

1 - PRINCIPLES OF CHEMISTRY 

Ionic bonding - 

• Atoms lose or gain electrons to form charged particles (ions) 
• Strongly attracted to one another because of the opposite charges - electrostatic attrcation 
• High melting and boiling points 
• Dot and cross diagrams (with square brackets and charge) 

Losing electrons = oxidation 
Gaining electrons = reduction 

Shell less than half full of electrons - 

• Left hand side of periodic table 
• Want to become more stable like the noble gases 
• Try to lose the electron - easier than completing shell
• Become positive 
• Gives electron to oppositely charges atom wanting to complete shell - stick together 

Shell more than half full of electrons - 

• Right hand side of periodic table (group 6 and 7) 
• Gain extra electrons to complete shell 
• Become negative 

- Groups 1, 2 (metals) and 6, 7 (non-metals) are the most likely to form ions  

Giant ionic structures - 

• Compounds with ionic bonding always have giant ionic structures 
• Ions held together in closely packed 3D lattice (attraction between oppositely charged ions - very strpmg) 
• A lot of energy is needed to overcome the strong forces of attraction - high melting and boiling points 
• The more charged it is, the stronger the forces of attractions are 

1 - PRINCIPLES OF CHEMISTRY 

Filtration - 

• Separates insoluble solid from liquid 
• Can be used in purification - solid impurities 

Crystallisation - 

• Separates soluble solid from solution 

1. Pour solution into evaporating dish 
2.Heat solution - some solvent evaporates, solution gets more concentrated 
3. Stop heating when crystals start to form 
4. Remove dish from heat, put in warm place for rest of solvent to evaporate 
5. Dry product - drying oven or desiccator 

Separating rock salt - 

• Mixture of salt and sand 
• Salt and sand are compounds 
• Salt = soluble - dissolves then forms as crystals
• Sand = insoluble - collects on filter paper

1. Grind up rock salt with pestle and mortar 
2. Dissolve in beaker and stir 
3. Filter through filter paper in funnel - filtering
4. Evaporate in evaporating dish - crystallisation 

Distillation - 

1 - Simple distillation 

• Separating out a liquid from a solution 
• Not similar boiling points 
• Can use to separate pure water from seawater - evaporate until just salt left in flask

1. Solution heated 
2. Lowest boiling point evaporates 
3. Vapour cooled, condenses and is collected 
4. Rest of solution left in flask 

2 - Fractional distillation 

• Mixture of liquids 
• Similar boiling points 
• Used for fractional distillation of crude oil at a refinery 

1. Put mixture in a flask 
2. Fractionating column on top 
3. Heat 
4. Liquids evaporate at different temperatures 
5. Lowest boiling point - when thermometer reaches its boiling point it will be a the top of the column 
6. Condensing through tube and collects into test tubes 


Chromatography - 

• Separates out dyes 
• Can help you identify dyes - compare to what you think it might be
• Different dyes move up the paper at different rates 

1. Draw pencil line near bottom of filter paper 
2. Add spots of different dyes on the line at regular intervals 
3. Put sheet in beaker of solvent, not touching the line (eg: water - depends on what is being tested, sometimes ethanol is needed) 
4. Put lid on container - stop solvent evaporating
5. Solvent carries dye up the paper and separates colours within it 

1 - PRINCIPLES OF CHEMISTRY 

Elements, compounds and mixtures - 

1 - Elements 

• Made up of one type of atom only 

2 - Compounds 

• Chemically bonded 
• 2 or more different elements - bonded together 
• eg: carbon dioxide - 1 carbon atom bonded to 2 oxygen atoms = molecule of carbon dioxide
• Difficult to separate original elements again 
• Properties of the compound generally very different from properties of the original elements 
• eg: iron sulphide 

3 - Mixtures 

• Easily separates 
• No chemical bond between different parts of the mixture 
• Can be separated by physical methods (eg: distillation) 
• eg: air - mixture of gases (nitrogen, oxygen, carbon dioxide, argon), can all be separated out easily 
• Crude oil - mixture of different length hydrocarbon molecules 

1 - PRINCIPLES OF CHEMISTRY 

Atoms - 

1 - Nucleus 

• Middle of atom 
• Protons and neutrons
• Positive charge 
• Contains most of the mass of the atom 

2 - Electrons 

• Move around nucleus in shells 
• Negatively charged 
• Cover a lot of space 
• Size of orbit depends on size of atom 
• Virtually no mass 

Protons =  heavy and positive 
Neutrons = heavy and neutral 
Electrons = small mass, negative 




Number of electrons = number of protons (in neutral atom/not isotope) - 

• Neutral atoms = no charge overall 
• Charge on electrons is same size as the charge on protons (but opposite) 
• Electrons added/removes - atom becomes a charged ion 

Atomic number and mass number - 

• Atomic number = no. of protons 
• Mass number = protons + neutrons 
• No. of neutrons = mass number - atomic number 

Molecules - 

• Groups of atoms (joined together) 
• Can be one element (H2, N2) or more than one element (H2O, CO2) 
• Held together by covalent bonds