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Year 9 Science Exam

January 2019

Revision Booklet

This booklet contains facts that you need to learn. You need to know

most of this booklet for your GCSE Science. If you learn it now it will give

you a head start!

Here are some suggestions for how to do it:

Start now! Don’t leave it until the last minute.

Tackle it one page at a time. You can’t learn it all at once.

Reorganise the information as a poster or a mind map.

Pick out key points and make your own, shorter notes that will be

easier to learn.

Break the information into chunks and write each on a card. Then

try to learn it one card at a time.

Pick a section, try to remember it, then try writing it out from

memory. Check what you wrote, correct your mistakes, and repeat!

Buddy up with a friend (or parent!) and test each other on one

section of the booklet.

Biology

Cells

An animal cell has:

Nucleus. This controls what the cell does.

Cytoplasm. This is a sort of jelly that fills the cell. It is where most chemical

reactions in the cell happen.

Cell membrane. This is a thin skin around the cell. It holds the cell together and

controls what goes in and out.

Mitochondria. These are where aerobic respiration happens.

Plant cells also have:

Cell wall: This is a stiff outer layer around the cell membrane. It supports the cell.

Vacuole: This is filled with cell sap. Cell sap is a liquid containing sugar and salts.

Chloroplasts: These are where photosynthesis happens.

Sperm cells

Sperm cells take the male DNA

to the egg.

A sperm cell has a tail to help it

swim to the egg.

It has a lot of mitochondria.

These provide energy for

swimming.

Diffusion

Diffusion is the spreading out of particles from an area of higher concentration to

an area of lower concentration.

Diffusion happens in solutions and gases. For example, the smell of perfume

diffuses through the air in a room.

The difference in concentration is called the concentration gradient. The bigger

the difference in concentration, the faster the diffusion rate.

A higher temperature will also give a faster diffusion rate. This is because the

particles have more energy, so move around faster.

Osmosis

Osmosis is the movement of water molecules across a partially permeable

membrane from a less concentrated solution to a more concentrated solution.

A partially permeable membrane is just one with very small holes in it.

Tiny molecules (like water) can pass through it, but bigger molecules can’t.

Overall, the water molecules moves from the less concentrated solution (where

there are lots of water molecules) to the more concentrated solution (where there

are fewer water molecules).

This means the more

concentrated solution

gets more dilute.

The water acts like it’s

trying to “even up” the

concentration on either

side of the membrane.

Water Sugar

Root hairs

Root hairs take in minerals and water from the soil.

Plant roots are covered in millions

of root hair cells.

These cells stick out into the soil

The “hairs” give the roots a large

surface area.

This is useful for absorbing water

and minerals from the soil.

Active transport

The concentration of minerals is usually higher in the root hair cells than in the

soil around them.

So root hair cells can’t use diffusion to take up minerals from the soil.

They use active transport instead.

Active transport allows the plant to absorb minerals from a very dilute solution in

the soil. It moves minerals against the concentration gradient.

But active transport needs energy from respiration to make it work.

Photosynthesis equation

Photosynthesis uses energy to change carbon dioxide and water into glucose

and oxygen.

It takes place in chloroplasts in plant cells.

Chloroplasts contain chlorophyll that absorbs light.

Energy is transferred to the chloroplasts from the environment by light.

Rate of photosynthesis

Pondweed can be used to measure the effect of light intensity on the rate of

photosynthesis.

1. The pondweed is placed in a beaker of water.

2. A ruler is used to measure a set distance from the pondweed

3. A light is placed at that distance. The pondweed in the beaker is left for 2 minutes

to acclimatise (get used to the new conditions).

4. Then the pondweed is left to photosynthesise for a set amount of time.

5. As it photosynthesises, oxygen is released. The number of oxygen bubbles

released are counted for an agreed amount of time and recorded in a results

table.

6. Steps 2-5 are repeated for at least 4 different distances.

7. The whole experiment is repeated twice more for each distance to get reliable

data.

Variables that must be controlled (kept the same) include:

the temperature of the water

the time the pondweed is left to photosynthesise

the time for which bubbles are counted

the amount of pondweed

the brightness of the lamp

Genetic engineering

The basic idea of genetic engineering is to transfer a gene for a desirable

characteristic from one organism’s DNA into another organism, so that it also has

the desirable characteristic.

1. A useful gene is cut from

one organism’s DNA

using enzymes.

2. The gene is inserted into

a vector, e.g. DNA from

a bacterial cell.

3. The vector is introduced

to the target organism,

e.g. the bacterial DNA is

put back into a bacterial

cell.

4. The target organism now

has the useful gene in its

DNA.

Immune response

We are given vaccinations containing dead or inactive pathogens to help protect us

against specific diseases.

At least one or even 2 vaccinations will be needed.

Shortly after the

vaccination the white

blood cells make

antibodies that help

destroy the invading

pathogens.

The more people that

are vaccinated, the

less chance there is

of someone catching

that disease, as they

are less likely to

come into contact

with anyone with the

symptoms.

2nd vaccination 1st vaccination

Chemistry

States of matter

State Diagram of

particles Arrangement of

particles

Relative distance between particles

Main movement of particles

Solid

Regular Very close Vibrate about fixed positions

Liquid

Random Close Move around each other

Gas

Random Far apart Move quickly in

all directions

State changes

1. Melting – Goes from a solid to a liquid

2. Evaporation – Goes from a liquid to a gas

3. Condensation – Goes from a gas to a liquid

4. Freezing – Goes from a liquid to a solid

Separation techniques

1. Filtration (e.g. sand and water)

Separates insoluble substances from soluble substances because particles of the

insoluble substance are too big to go through the filter paper

2. Crystallisation (e.g. salt dissolved in water)

Separates dissolved solid substances from a solvent by heating slowly so the

solvent evaporates and solid crystals form.

3. Simple distillation (e.g. salt dissolved in water)

Used when you want to purify a solvent, such as water that has salts dissolved

in it. The sample is heated so that it evaporates and then the solvent is collected

as it condenses.

4. Fractional distillation (e.g. crude oil)

Separates mixtures of lots of liquids that have different boiling points.

Periodic table

The periodic table contains elements.

Metals Non-metals

On the left-hand side On the right-hand side

Shiny Dull

High melting point Low melting points

Malleable and ductile Brittle

Good thermal conductors Poor thermal conductors

Good electrical conductors Poor electrical conductors

Chemical reactions

1. In a chemical reaction the total mass at the start of the reaction is the same as

the total mass at the end of the reaction.

This is known as conservation of mass.

2. The chemicals that you start with are called reactants.

The chemicals that are produced in the reaction are called products.

An equation for a chemical reaction is written using an arrow:

Reactants Products

3. Acids have a pH of 0 to 6.9

Alkalis have a pH of 7.1 to 14

A pH of 7.0 is neutral.

4. When acids react they make different salts:

Hydrochloric acid (HCl) → chloride

Sulfuric acid (H2SO4) → sulfate

5. Metal oxides, hydroxides and carbonates react with acids. These are the general

equations for these reactions.

metal oxide + acid → a salt + water

metal hydroxide + acid → a salt + water.

metal carbonate + acid → a salt + water + carbon dioxide

6. To make a salt from a metal oxide.

A. Add the metal oxide to the acid in excess (no more will dissolve)

B. Filter the solution to remove the excess base

C. Heat the solution to evaporate most of the water

D. Leave the solution to let the last of the water evaporate and allow crystals to

form

8. In some chemical reactions gases are formed. You can test for these by:

A. Hydrogen. Place a lit splint in the gas it will make a squeaky pop sound.

B. Oxygen. Place a glowing splint in the gas it will relight

C. Carbon dioxide. Bubble the gas through limewater, the limewater will go cloudy.

9. Combustion (burning) is an important chemical reaction. For a fuel to burn it

needs oxygen. The chemical equation for combustion is

Fuel + Oxygen Carbon Dioxide + Water

Physics

Space

The Solar System

Everything in the solar system orbits the Sun.

The order of the planets is:

Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune

Stars, galaxies and the Universe

The Sun is a star.

Galaxies are groups of billions of stars.

Our galaxy is called the Milky Way.

The Universe is made up of billions of galaxies.

Light years

A light year is the distance travelled by light in one year.

Gravity

All objects attract other objects due to the force of gravity.

There is gravity everywhere, even in space.

Gravity gets weaker as you move away from a planet, but never disappears

entirely.

The strength of gravity is called ‘g’ (gravitational field strength).

The value of ‘g’ is different on different planets.

On Earth, g is about 9.8 N/kg.

Days, years and seasons

Day Caused by the rotation of the Earth, every 24 hours.

It is daylight when our side of the Earth faces the Sun.

Year Caused by the Earth orbiting the Sun, every 365.25 days.

Seasons

Caused by the tilt of the Earth’s axis.

In summer we are tilted towards the Sun. We have longer days

and the Sun is higher in the sky, so it is warmer.

Energy

Energy cannot be created or destroyed, only transferred between different forms.

Energy store Stored by…

Kinetic … any moving object.

Chemical … food, fossil fuels, batteries.

Nuclear … fuel used in nuclear power stations (e.g. uranium).

Gravitational … any object that has been lifted up.

Elastic … any object that has been squashed or stretched.

Thermal … a hot object.

Energy transfer Transferred …

Light … by a light wave.

Sound … by a sound wave.

Electrical … by an electric circuit.

Thermal … from a hot to a cold object.

Mechanical … by a force acting on a moving object.

Energy Resources

Renewable energy resources will never run out.

Renewable Non-renewable

Wind Wave Solar Tidal

Hydroelectric Biomass

Geothermal

Coal Oil

Gas Nuclear

Forces

All forces are measured in newtons (N)

Weight Force of gravity pulling you down.

Upthrust Force that makes you float in air or water.

Reaction

force Force that supports you on your chair.

Tension Force in a tight string or elastic band that stops it stretching any

further.

Friction Force when two surfaces rub. Makes it harder for things to move.

Balanced forces

If two equal forces act in opposite directions, then the forces are balanced.

If an object is not moving, the forces must be balanced.

If an object is moving at a constant speed, the forces must also be balanced.

Unbalanced forces

If the forces on an object are unbalanced, then it must be doing one of these things:

• Changing speed (speeding up or slowing down

• Changing direction

Resultant force

Resultant force is the total or overall force on an object.

This hedgehog has… 200 N + 150 N = 350 N force to the right

50 N force to the left

So the resultant force is 350 N - 50 N = 300 N to the right

200 N

150 N 50 N

Electricity

Circuit symbols

Cell Switch Ammeter Voltmeter

Light bulb Motor Resistor

Waves

Oscilloscope traces of sound waves

low, quiet low, loud high, loud

Amplitude: The height of the traces tells you how loud the sound is.

Frequency: The number of vibrations in one second.

It is measured in hertz (Hz).

Closer together waves means higher frequency.

Longitudinal wave

Vibration is parallel to

the direction of travel

Transverse wave

Vibration is at right

angles to the direction of

travel

Equations

energy = power × time E = P × t

work done = force × distance moved W = F × d

force = mass × acceleration F = m × a

distance = speed × time d = s × t

voltage = current × resistance V = I × R

wave speed = frequency × wavelength v = f × λ

weight = mass × gravitational field strength W = m × g

Units

Quantity Unit name Unit symbol

energy or work done joules J

power watts W

time seconds s

force (including weight) newtons N

distance or wavelength metres m

speed metres per second m/s

voltage volts V

current amps A

resistance ohms Ω

frequency hertz Hz

mass kilograms kg

acceleration metres per second squared m/s2

gravitational field strength newtons per kilogram N/kg

Unit Prefixes

Prefix Name Value d deci 10-1

T tera 1012 c centi 10-2

G giga 109 m milli 10-3

M mega 106 μ micro 10-6

k kilo 103 n nano 10-9