Revision

longer.

Food additives.

• Make food look and taste better, and last • Anti-oxidants stop the food from reacting with oxygen.

• Emulsifiers help oil and water mix.

– Hydrophobic and hydrophilic.

• The E means it has passed a safety test, the number tells you what it does.

Food packaging.

• Active packaging – Change something about what is in side the packet.

– Release a gas.

– Heat up or cool the contents.

• Intelligent packaging.

– Monitors what’s going on in the packet.

– Tell you when its gone off – Tell the GP about not taking pills.

Cooking.

• Proteins denature.

– Heat changes their shape permanently.

• Starch grains burst.

• Cooking is an irreversible chemical change.

• NaHCO 3 → Na 2 CO 3 + CO 2 + H 2 O

Perfume.

• Acid + Alcohol → Ester and Water.

– Easily evaporates.

– Non toxic.

– Doesn't react with water.

– Doesn't irritate your skin.

– Insoluble in water.

Solutions.

• A solute dissolves in a solvent making a solution.

• Its all about attraction.

– The solvent needs to be able to break the bonds of the solute and make stronger bonds with them.

What is oil made of???

•Oil is a Mixture of Hydrocarbons •They are called: • Alkanes and • Alkenes

Chemicals

• Name chemical formula display formula H methane, CH 4 H C H H 3d shape.

An example of an alkane • Methane • All single bonds • Saturated

an example of an alkene • Ethene • Contains a double bond • unsaturated

Alkanes and alkenes.

• Alkanes: – C-C – ‘saturated‘ – C

n H 2n+2

– Can’t make polymers.

– Very unreactive.

– Does nothing to bromine water.

• Alkenes: – C=C – 'unsaturated' – C

n H 2n

– Used to make polymers.

– Very reactive.

– Turns bromine colourless.

Naming hydrocarbons

NO. OF CARBONS NAME 1 2 3 4 5 Meth Eth Prop But Pent-

Testing for saturation

• What happens to the bromine water in the presence of an: – Alkane?

• No observable reactions – Alkene? • The bromine water goes colourless

Kinetic theory.

• Solid – Strong forces holding particles together.

• Liquid – Weak forces holding them together.

• Gas.

– Virtually no forces holding them together.

• Volatility.

– Liquids evaporate when particles get enough energy to break free of the forces.

Fractional distillation.

• Hydrocarbon molecules contain only carbon and hydrogen atoms. • Crude oil can be separated by fractional distillation, – because they have different boiling and

condensation points.

• The crude oil is heated to vapourise it (evaporated or boiled).

• The most volatile fraction, i.e. the molecules with the lowest boiling points, boil or evaporate off first and go to the top of the column.

How do we separate this mixture??

• Fractional Distillation • As you go up the column to the: – Boiling point decreases – Intermolecular forces decrease – Volatility/ignition increases

Hydrocarbon Bonds • Down the pic above the molecule gets ...

• ... bigger as the carbon atom number in the molecule increases. • ... more viscous as the intermolecular forces between molecules increases.

• ... higher melting point as more energy is needed to overcome the intermolecular forces holding the molecules together. • ... higher boiling point as more energy is needed to overcome the increasing intermolecular forces between the liquid molecules.

• ... less flammable as they become less volatile, again due to increasing intermolecular forces.

How do we make the fractions more useful??

• What process is used to break long carbon molecules (like tar) into smaller, more useful molecules (like petrol)?

• Cracking • Need a catalyst • High pressure

Cracking.

• In the catalytic cracker long chain molecules are split apart or ‘cracked’.

• This is another example of thermal decomposition.

H H H C C H H H H H H H H C C C C C C H H H H H H H Octane hexane H Used as a fuel H H C C H H Heat pressure H H H H C C C C H H H H H catalyst + H H C C H H C 8 H 18  C 6 H 14 + C 2 H 4 ethene Ethene is used to make plastics

Polymers.

• Monomers stick together and make polymers.

• Unsaturated monomers have a double bond between 2 carbons.

H H C C H H H H H C C H H C C H H C C H H C C H H C C H H H H H H H H H

1 2 3 4 5 thousands

H And lots more..

This is called

addition polymerisation

and is written as: n H H C C H H ethene Pressure high temperature catalyst H H C C H H n poly(e)thene

• Thermoset – Hard, and rigid.

– Resist higher temps – Can only be moulded once.

– E.g. Polyester.

• Thermoplastics – Soften easily.

– Can be re moulded many times.

– E.g. Polystyrene

Making Polymers

• What do we start with???

• An AlKENE

Making Polymers

• The DOUBLE bond is broken leaving:

Polypropene

• Ethene is only one alkene. Other unsaturated molecules such as propene, vinyl chloride and styrene can also be polymerised to produce a range of plastics. E.g. propene n H H H C C C H H H propene H CH 3 C C H H n Poly(propene)

• PVC n H H Cl C C H Vinyl chloride H C H Cl C H pvc n

Uses of polymers.

• Properties decide what plastics are used for.

• They are not biodegradable, burning them gives off poisonous smoke, and recycling is expensive.

• Gortex 3 layers: holes large enough for sweat but too small for rain.

Fuels.

• Oil is running out, and is none renewable.

• Oil slicks, acid rain, and green house problems.

• Things that are important about choosing fuels are: – How much energy it gives out.

– How much it costs.

– How easy it is to store.

– How poisonous it is.

– How much pollution it gives off.

vapour.

Burning fuels.

• Burning hydrocarbons always gives off water • Enough oxygen allows complete combustion giving off carbon dioxide as well.

• Too little oxygen gives off carbon monoxide instead (and less oxygen).

• Cobalt blue goes pink for water • Lime water goes cloudy for carbon dioxide.

Burning hydrocarbons The apparatus below is used to test the products of combustion of a hydrocarbon.

Suction pump ice water Lime water Candle wax is the hydrocarbon here Liquid collected can be tested with anhydrous cobalt chloride paper (blue  pink).

any hydrocarbon + oxygen  water + carbon dioxide

Complete combustion • Alkanes are not especially reactive but they do have one very important reaction: combustion.

• With an adequate supply of air they react to form carbon dioxide and water. Methane + oxygen  water + carbon dioxide CH 4 + 2O 2  2H 2 O + CO 2

Incomplete Combustion of Alkanes • In the absence of an adequate supply of air, alkanes may react to form carbon monoxide and water. • Carbon monoxide is highly poisonous and this is one reason why gas boilers must be serviced regularly.

A carbon monoxide detector

Methane + oxygen  water + carbon monoxide 2CH 4 + 3O 2  4H 2 O + 2CO

Energy.

• Exothermic – Gives out energy – More bonds are made than broken • Endothermic – Takes in energy.

– More bonds are broken than made.

It takes 4.2 Joules of energy to increase the temp of 1g of water by 1C Energy transferred (J) = mass of water (g) x 4.2 x temp change (C) Energy of fuel (J/g) = energy transferred (J) / mass of fuel burnt (g)

Energy in a reaction

• Energy transferred = Mass of water x 4.2 x change in temperature

5 4 3 2 1 0 -1 0 -2 -3 5 10 Time Endothermic Exothermic 15

Energy for the Home Module P1 Revision • The thermal energy in a mass is the total energy of all the particles in the mass • Thermal energy (heat) is measured in joules (J) • The temperature is a measure of how hot something is (how fast the average particle is moving) • Temperature is measured in degrees Celsius (°C)

Like water flowing downhill, from higher places to lower places • Thermal energy transfers from high temperature places to low temperature places • The bigger the temperature difference the quicker the heat energy transfers

The Thermogram

• Temperature is shown by the colour • Hot = red/yellow • Cold = blue

An Absolute Scale

• The lowest possible temperature is -273 o C • This is taken as 0 o on the Absolute Scale

Heating and Cooling

• To raise the temperature of an object energy must be added (by heating it) • To lower the temperature of an object energy must be taken away (by cooling it)

Specific Heat Capacity, SHC

• The amount of energy added or subtracted to change the temperature of a substance depends on: • Its mass • The material • The temperature change

Specific Heat Capacity, SHC

• The Specific Heat Capacity of a substance is the energy needed to change the temperature 1 kg of the substance by 1 o • The greater the SHC the more heat energy it can store • Energy required/released = mass x SHC x temperature change

Specific Latent Heat, SLH

• When a solid melts or a liquid boils it requires energy, even though its temperature does not change • The energy is needed to break the bonds between the molecules

Specific Latent Heat, SLH

• When a liquid solidifies or a gas condenses energy is released even though the temperature does not change • The energy is released as the atoms join together and slow down

Specific Latent Heat, SLH

• The Specific Latent Heat, SLH, is the energy required or released by 1 kg of a substance when it melts or freezes, evaporates or condenses • Energy transferred = mass x specific latent heat

Changes of state

30 20 10 0 90 80 70 60 50 40 BOILING MELTING 1 2 3 4 5 GAS LIQUID SOLID 6

Time

7 8 9 CONDENSING SOLIDIFYING 10 11 12

Insulation

• Air is a good insulator, (all gases are good insulators) Any material that traps pockets of air is a good insulating material Eg: Expanded polystyrene, fibreglass wool, Double glazing, feathers, fur

Insulating the house • Loft insulation • Cavity Wall insulation • Double glazing • Carpets • Draught excluders

Payback time

• Payback time = Original cost ÷ annual saving

Efficiency

• The more efficient a machine or device is, the more of its INPUT energy is transferred into a USEFUL energy OUTPUT 90 J Light Energy USEFUL OUTPUT 100 J Electrical Energy INPUT 10 J Heat Energy WASTED OUTPUT Efficiency = 90/100 = 0.9 = 90%

Payback time

• Money spent on insulating your home is money well spent – but some methods are better than others: • Loft insulation may cost £500 to buy, and save £250 each year in heating costs • So it would take 2 years to save the original cost: Payback time is 2 Years

Heat Energy Transfer (1)

• CONDUCTION:- Transfer of Thermal Energy via particle to particle, atom to atom – Mainly occurs in solids – “Hotter” Particles/atoms vibrate faster, taking up more space so the solid expands – Best conductors are metals, due to free electrons enabling rapid transfer of energy

Heat Energy Transfer (2)

• CONVECTION:- transfer of heat energy through liquids and gases – “Hotter” particles/atoms move faster, so they take up more space and the gas or liquid expands and becomes less dense – “Hotter,” less dense, masses of water or air will rise – “Colder”, more dense, masses of water or air will sink • CONVECTION CURRENTS will develop, transferring energy everywhere else

Heat Energy Transfer (3)

• RADIATION:- EVERY object that is HOTTER than its surroundings will emit heat energy as INFRARED RADIATION until it is the same temperature as its surroundings • This can be seen by infrared cameras and sometimes felt by the skin

INFRARED (1)

• Black surfaces absorb infrared best – Black cars get hot in the sun, white ones stay cool • Black surfaces emit infrared best – Radiators should be black – but who wants black radiators?

• White/silver surfaces reflect infrared – NEWS FLASH! Space tourists travel to the sun behind a giant mirror and survive!

• White/silver surfaces emit least – So why is my radiator white?!

INFRARED (2)

• USED FOR: – Burglar alarms: “heat sensors” detect infrared – Cooking: infrared heats the surface of food, cooking it – Control: Remote controls for TVs, videos, DVDs – Information: transfer of data to/from computer mouse

MICROWAVES

• Have longer wavelength (lower frequency) than infrared, so transfer less energy.

• Are reflected by metals, but go through plastics and glass • Used by mobile phones, satellites and radar • One particular wavelength used for cooking because it is absorbed by water molecules which then move more quickly (ie they get “hotter”) – this then cooks the food

ANALOGUE SIGNALS

• These are waves that continuously vary • They can have many different values • Any interference can not be removed: signal quality can only get worse

DIGITAL SIGNALS

• These are waves that only have two values: – High/Low 1 or 0 On/Off • Interference or distortion can be removed or is not recognised by the receiver • Signals can be boosted or amplified without increasing interference • More data can be sent each second through multiplexing (interweaving) different signals on the same data line

DIGITAL SIGNALS

Computer Binary Code Surface of DVD disc Digital signal

WAVES in general

Wavelength Amplitude Frequency = number of cycles (0scilations) per second (Hertz) Speed of wave (m/s) = wavelength (m) x frequency (Hz)

Wave Characteristics

• There are two main types of wave – Longitudinal, e.g. Sound, P-waves – Transverse, e.g. Light, S-waves Vibrational direction Vibrational direction Energy flow

Transverse Wave LongitudinalWave

Energy flow

Wave Characteristics

• All waves can be REFLECTED The angle of reflection = the angle of incidence

TOTAL INTERNAL REFLECTION

Optical fibres can carry signals without losing as much energy Signals are more secure: more difficult to listen in

Wave Characteristics

• All waves can be REFRACTED • Because light SLOWS down in more dense materials like glass

Wave Characteristics

• All waves can be DIFFRACTED • When a gap or obstacle is the same width as the wavelength the waves spread out through it, or around it • When the wavelength is smaller the spreading is less obvious

ELECTROMAGNETIC WAVES

• Electromagnetic waves are transverse • At the lowest energy, lowest frequency and longest wavelength are radiowaves • Next come microwaves, infrared, visible, ultraviolet, x-rays • At the highest energy, highest frequency and shortest wavelength are gamma rays

LASERS

• Laser light consists of lightwaves that are all in phase with each other • This makes a tight beam with great intensity • Can be used to cut wood, steel and flesh with great accuracy • Reflects precisely off CD and DVD discs

Wireless Technology

• Transmitter and receiver do not need to be physically connected • Available 24/7 • Radio waves can be reflected around the world through the IONOSPHERE (a layer of ionised air high in the atmosphere)

Wireless Technology

• Microwaves can be sent around the world by being RECEIVED and RE-TRANSMITTED from geostationary satellites • Microwaves can be transmitted from phone mast to phone mast if in line of sight NOT TO SCALE

INTERFERENCE

• Different TV and radio channels use different frequencies to broadcast their programs • If these frequencies are nearly the same the receiving TV or radio will get both programs – this is INTERFERENCE

SEISMIC WAVES : P-WAVES

• P-Waves = Primary waves = “Pressure” waves = longitudinal waves • Are transmitted through solids, liquids and gasses • The denser the substance the quicker they travel • Sound travels at – 330m/s in air 1500m/s in water 5000m/s in steel

SEISMIC WAVES : S-WAVES

• S-waves = Secondary waves = “sideways” waves = transverse waves • Only travel through solids or semi solid material • Travel more slowly through the Earth than P Waves

Structure of the Earth This is what the interior looks like – we think!

But how do we know?

Structure of the Earth

• If the Earth was simply solid all the way through – Then the waves from an earthquake would be felt everywhere around the world

STRUCTURE OF THE EARTH What the S-Waves tell us • Observation: The S-Waves are not detected over nearly half of the Earth • Explanation: The waves are blocked by a

Liquid Core

STRUCTURE OF THE EARTH What P-Waves tell us • Observation: There is a shadow zone where P-Waves are not detected • Explanation: A liquid core causes refraction of the waves

ULTRAVIOLET RADIATION

• UV radiation can damage DNA in skin cells • Small amounts cause tanning • Large amounts may cause skin cancer • Dark skin absorbs some UV reducing the amount reaching the deeper layers of skin • The OZONE layer absorbs some UV reducing the amount reaching the Earth’s surface • CFCs reduce OZONE, CFCS have been banned from current use

CLIMATE CHANGE

• The Earth’s climate changes naturally as the sun changes • Volcanic dust and ash and man-made pollution can reflect sunlight away – cooling the planet • Greenhouse gases “trap” heat in – warming the planet • Greenhouse gases include CO 2 , Methane and Nitrous Oxides (NOXs)

That’s all folks

• Remember – Read the question at least twice, or until you understand what it is asking you – If the question asks you to “Describe...” or “Explain…” then write a complete sentence for each mark that can be given – Read through your answers to make sure that they make sense – Nonsense award Examiners marks cannot for!

Biology

Unit 1

What’s the difference between fitness and health?

How can we measure fitness?

• Strength • Stamina • Speed • Flexibility • Agility • Cardiovascular efficiency

• How many words can you find that are to do with fitness and exercise?

N U V A Y G E R D O X B A U J Q A D B E A J G N D B C U L D E S O E A X R U L S A P S P F E V E I L A N E T L K R S A S R R P N R M L O R T W V A Q E T O T B B H B T D B R V N U I D E P I D S G W V D C O K C D C Z Y H A C I D N I C A L A C T

Your beating heart gives your blood pressure

• Blood pressure can be: –Diastolic (When the heart

relaxes)

–Systolic (When the heart

contracts)

• What are the units for blood

pressure?

–mmHg

Blood pressure too high?!

• Burst blood vessels • Damage to brain • Stroke • Kidney damage

Blood pressure too low?!

• Dizziness • Fainting • Poor circulation

•Blood pressure is affected by age and lifestyle (diet, smoking, alcohol…)

RESPIRATION

What’s the equation?

GLUCOSE

PLUS

OXYGEN

GIVES

CARBON DIOXIDE

PLUS

WATER

PLUS

ENERGY

C 6 H 12 O 6 ENERGY) + 6O 2  6CO 2 + 6H 2 O (+

•Can you remember it?

•Try saying it to yourself!

Glucose + oxygen  (energy) carbon dioxide + water + C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O (+ ENERGY)

FATIGUE

•When we do hard exercise, we respire ANAEROBICALLY and LACTIC ACID builds up in our muscles.

After exercise…

•Continued panting replaces oxygen allowing aerobic respiration •Increased heart rate ensures blood carries lactic acid away to the liver.

ANAEROBIC RESPIRATION

• Respiration without oxygen!

• Glucose  lactic acid + energy • MUCH LESS ENERGY RELEASED IN ANAEROBIC RESPIRATION

BALANCED DIETS

• Vary depending on age, gender and amount of activity • Carbohydrate – The body’s energy resource • Fat – An insulator and an energy resource • Protein – For growth and repair • Vitamins – Keep the body functioning • Minerals – Keep the body functioning • Fibre – Keeps food moving along the gut

Can you remember the food types and what they are needed for?

• Carbohydrate – The body’s energy resource • Fat – An insulator and an energy resource • Protein – For growth and repair • Vitamins – Keep the body functioning • Minerals – • Fibre – Keep the body functioning Keeps food moving along the gut

CARBOHYDRATES

Are made from… SIMPLE SUGARS (E.G. GLUCOSE)

FATS

• Are made from… • FATTY ACIDS AND GLYCEROL

PROTEINS

• Are made from… • AMINO ACIDS

•How do religion, personal choice, (e.g. vegetarians, vegans) and medical issues (e.g. food allergies) influence a person’s diet?

• Vegetarians – will not eat meat or fish • Vegans – will not eat any food of animal origin, including milk, cheese and eggs • Jews do not eat pork • Muslims eat halal meat

• Animal proteins are known as ‘first class’ proteins… • …because they contain all the essential amino acids the body needs.

• Lack of protein causes KWASHIORKOR

• BMI (body mass index) = mass (g) (height (m)) 2 • BMI can be used to help us understand whether a person is underweight, normal, overweight or obese

•A desire for perfection, low self-esteem and poor self image can lead to a poor diet and increased risks of poor health.

DIGESTION

CAN YOU

down of large insoluble food

MEMORISE

soluble ones by absorption enzymes into the blood for

•FOOD MOLECULES ARE BROKEN DOWN BY SPECIFIC ENZYMES.

CARBOHYDRATES are broken down by CARBOHYDR ASE

PROTEIN is broken down by PROTE ASE

FAT/LIPID is broken down by LIP ASE

Where does digestion take place?

• The mouth • The stomach • The small intestine • Stomach acid aids enzyme function.

• Small molecules are absorbed into the blood in the small intestine by DIFFUSION.

Immunity to disease

• Active: – The body remembers a pathogen invasion and white blood cells can respond quickly next time it happens!

• Passive: – Injecting a person with antibodies (e.g. Protection from a snake bite)

The immune response • The body’ white blood cells produce antibody , specific to antigen on the surface of the pathogen

4

Can you order these pictures?

2 5 1 3

TYPES OF CANCER

• Benign – Tumour cells slow to divide and harmless (warts) • Malignant – Tumour spreads throughout body causing cancer

THE EYE

Can you remember the labels?

REFLEXES ARE...

T A

F A P

R U T O S T O E M A C T T I I V E C

A motor neurone

• Sensory neurones carry impulses ________ from a sense organ.

• Motor neurones carry impulses to an _________ (muscle or gland)

• When signals pass from one neurone to another, they have to cross a gap. This is called...

• THE SYNAPSE • Impulses trigger transmitter substances like ACETYLCOLINE to diffuse across the synapse.

DRUGS

What are the effects of the following types of drug?

• Depressants • Hallucinogens • Painkillers • Performance enhancers • Stimulants

• Depressants – slow down brain function • Hallucinogens- change what a person sees/hears • Painkillers – Stop nerve impulses so no pain is felt • Performance enhancers – develop muscles • Stimulants – speed up brain function

The effects of drinking alcohol

• Do silly things • Easily lose balance • Find it hard to talk clearly • Liver cirrhosis • Drink driving

The effects of smoking tobacco

• Nicotine is addictive • Carbon monoxide reduces oxygen absorption • Particulates collect and block lungs • Tar causes lung cancer

HOMEOSTASIS • Keeping everything in balance – Water – Temperature – Blood sugar – Hormones

Controlling heat loss

• Controlled by the hypothalmus: – Vasoconstriction - capillaries in the skin become narrower, less blood flows through them, less heat is lost – Vasodilation – capillaries in the skin widen, more blood flows through them, more heat is lost

•TOO HOT – HYPERTHERMIA (NORMAL BODY TEMPERATURE IS 37 DEGREES CELCIUS) •TOO COLD HYPOTHERMIA

Female sex hormones, progesterone and oestrogen, are produced in The pancreas produces the hormone controls blood sugar level The male sex hormone, testosterone, is produced in the

Control of blood sugar level

• Glucose too high: the liver Insulin converts glucose to glycogen and stores it in Kidneys remove glucose from the blood and excrete it in urine

The genetic code is a set of instructions that provide each organism with its characteristics

DNA is a double helix

• It looks like a twisted ladder • The rungs of the ladder are made up of 4 bases .

• A, C, T and G • A always pairs with T • C always pairs with G

• All cells contain all the genetic information for all characteristics in an organism.

• Genes are switched on if they are being used and switched off if they aren’t

How DNA controls characteristics

COPY OF DNA TAKEN TO RIBOSOMES SEQUENCE OF 3 BASES DECIDES ON AMINO ACID AMINO ACIDS JOIN TO MAKE PROTEIN (E.G. AN ENZYME) ENZYMES CONTROL REACTIONS FOR MAKING EYE PIGMENT

Females have 2 ‘X’ chromosomes

Males have an X and a Y chromosome

• Humans have 46 chromosomes (23 pairs) • Human sex cells (gametes) contain 23 chromosomes • When two sex cells meet  = 46!

• THIS IS FERTILISATION 23 +23

How do we get our characteristics?

• Genes are inherited • Humans show variation (we all have differences) • What causes variation?

Causes of variation

• Genes mixed up in gametes • Genes coming from two different parents (fertilisation) • Mutations – Radiation – Chemicals (mustard gas)

What’s the problem with mutations?

•A change in the base sequence results in a change in the amino acid sequence, so the whole protein can be affected

Can you think of any conditions that are inherited?

• Red – green colour blindness • Cystic fibrosis • Sickle cell anaemia • Haemophilia

DOMINANT OR RECESSIVE?

• Dominant characteristics: – A curved little finger – Ability to roll your tongue • Dominant characteristics tend to be more common than recessive characteristics.