AQA GCSE 9-1 Combined Science Trilogy Comprehensive Flashcards

What are the two main types of cell?

prokaryotic and eukaryotic

How is magnification calculated?

the size of the image divided by the size of the real object

What are chromosomes made of?

DNA

Osmosis

the process by which water molecules move across a semi-permeable membrane from a dilute solution to a more concentrated one.

What is an organ?

a group of different tissues working together to perform a specific job.

What are the three main types of digestive enzymes?

protease, lipase and carbohydrase

What are the three different types of blood vessels?

arteries, veins and capillaries

What two treatments can be used for coronary heart disease?

stents to keep coronary arteries open or statins to reduce cholesterol.

Name the process by which water evaporates through stomata in the leaves.

transpiration

What is the vector of malaria?

A type of mosquito

How can a person be made immune to a specific disease?

vaccination

What is MRSA?

a strain of bacteria that is resistant to antibiotics.

What two products are produced when carbon dioxide and water combine in photosyntesis?

glucose and oxygen

What is anaerobic respiration in yeast cells called?

fermentation

What is the difference between receptors and effectors?

The first are cells which detect stimuli, whereas the latter are parts of the body (e.g. muscles or glands) which produce responses to stimuli.

What are the chemical messengers produced by the glands of the endocrine system?

hormones

What four hormones are involved in the menstrual cycle?

follicle stimulating hormone (FSH), oestrogen, luteinising hormone (LH) and progesterone.

What type of cell division forms gametes?

meiosis

What word describes having two different alleles for a gene?

heterozygous

What process is the gradual change in the inherited characteristics of a population over time?

evolution

How is selective breeding different from genetic engineering?

The first is the traditional, natural process of breeding plants and animals with certain desirable genetic features. The latter is a modern, faster way of bringing about change in organisms. It is the artificial process of transplanting genes for a desired characteristic into an organism.

What is the classification system called in which organisms are given two-part name made up of their genus + species?

The binomial system.

What is a population?

A group of individuals of one species living in a habitat.

What are the top consumers in a food chain called?

Apex predators

Name two gases that contribute to global warming.

Carbon dioxide and methane.

Explain how fractional distillation can be used to separate a mixture

It is used to separate components with different boiling points from a mixture. The mixture is heated gradually and each component is collected when it boils.

If an element has different isotopes, what does this mean?

Same number of protons but a different number of neutrons in each atom.

What are the elements in these groups of the Periodic Table known as?
a) Group 0
b) Group 1
c) Group 7

a) Group 0 - the noble gases
b) Group 1 - the alkali metals
c) Group 7 - the halogens

Complete the table.
State of substance - State symbol
solid - (...)
... - (l)
... - (g)
(...) dissolved in - (...)
water

solid - (s)
liquid - (l)
gas - (g)
(aqueous) dissolved - (aq)
in water

Describe what happens to a metal atom and a non-metal atom when an ionic bond forms between them.

The metal atoms lose electrons to become positively charged ions. The electrons are transferred to the non-metal atoms, which gain electrons to become negatively charged ions.

Describe what happens when once chlorine atom forms a bond with another chlorine atom.

An electron from each atom is shared so that each atom has a complete outer shell of electrons.

Explain why most polymers are solid at room temperature.

The atoms within polymer molecules are covalent bonds. The intermolecular forces between the large polymer molecules are also quite strong.

Why do chemical symbol equations always need to be balanced.

Mass is conserved. In a chemical reaction, no atoms are made or lost.

Use these words
to complete the
sentences that
follow. (Use each
word once only.)
together loses gains
In oxidation reactions, a substance
often ... oxygen.
In reduction reactions, a substance
often ... oxygen.
Oxidation and reduction
always occur ... .

In oxidation reactions, a substance often gains oxygen.
In reduction reactions, a substance often loses oxygen.
Oxidation and reduction
always occur together.

Which of the following sentences are true and which are false?
A. Three moles of potassium atoms contain a total of just over 18 x 10^23 atoms.
B. Sodium has a lower relative atomic mass than potassium, so three moles of sodium atoms contain fewer than 18 x 10^23 atoms.

A is true: one mole is 6.02 x 10^23 atoms, so 3 x 6.02 x 10^23 = 18.06 x 10^23 atoms.
B is false: one mole of any element always contains 6.02 x 10^23 atoms

Why is the following reaction called a neutralisation reaction?
HCl(aq) + KOH(aq) -> KCl(aq) + H2O(l)

Hydrochloric acid (HCl)
neutralises the alkali
potassium hydroxide (KOH).
The solution that remains has
a pH of 7, meaning that it is
neutral.

Explain why electrolysis is an expensive way of extracting metals from their ores.

Electrolysis requires a lot of heat and electrical energy.

What is the difference between endothermic and exothermic reactions?

Endothermic reactions take in
energy from the surroundings
and cause a temperature drop.
Exothermic reactions give out
energy to the surroundings and
cause a temperature rise.

If a reaction is endothermic, what does
this tell us about the energy needed to break and make bonds in the reaction?

An endothermic reaction
takes in energy from the
surroundings. This means
that the energy needed to
break bonds is greater than
the energy given out by the
making of bonds.

A sample of solid
calcium carbonate
is divided precisely
into two equal
masses. One half is a single
solid piece, which is then
reacted with an acid. The
other half is broken into small
pieces and reacted with a
fresh sample of the same acid.
Which half will react faster,
and why?

The half that is broken into
small pieces will react faster.
This is because small pieces
have a large surface area
in relation to their volume.
More solid particles are
exposed to contact with
acid particles, so there are
more collisions and a faster
reaction.

Choose the correct phrase
from this list to complete
the sentence that follows.
much less than
exactly the same as
much more than
When a reversible reaction takes place
in a closed system, an equilibrium
is achieved when the rate of the
backward reaction is ... the rate of
the forward reaction.

When a reversible reaction
takes place in a closed
system, an equilibrium is
achieved when the rate of the
backward reaction is exactly
the same as the rate of the
forward reaction.

Choose the correct
general formula for
alkanes from the
following list.
CnH2n−2
C2nHn
CnH2n
CnH2n+2

CnH2n+2

What are the two main methods
of cracking hydrocarbons?

steam cracking and catalytic cracking.

Complete the following table that describes tests for different gases.
Gas Test for gas
... Turns limewater cloudy
Hydrogen ...
Oxygen ...
... Turns damp indicator paper white.

Gas Test for gas
Carbon Turns limewater Dioxide cloudy
Hydrogen Burns with a . squeaky pop
Oxygen Relights a glowing . splint
Chlorine Turns damp . indicator paper . white.

Describe the effects that the evolution of plants had on the Earth's atmosphere.

Plants use carbon dioxide
and water to produce
oxygen in the reaction called
photosynthesis. As more
plants evolved, the amount
of oxygen in the atmosphere
increased. Eventually the
levels of oxygen were enough
for land-based animals that
breathed oxygen from the
air to evolve.

What is the carbon footprint?

The total amount of
carbon dioxide and other
greenhouse gases that are
emitted by a product, service or event over its full life cycle.

Why can't we release our waste water directly into the environment?

Waste water can contain
toxic chemicals, harmful
microorganisms and other
organic matter. All these
things can cause pollution
and affect plants and animals,
including humans.

What is the purpose of a life cycle assessment?

It provides a way of comparing
different products to see
which cause least damage to
the environment, over their
whole lifetime.

A force is a vector quantity.
What does this mean?

It has a direction as well
as a magnitude.

Define the spring constant
and write an equation for
calculating it.

It is a measure of how easy it is to
stretch or compress a spring. = force / extension

What is a typical
speed for a person walking?
Choose from:
2.5 m/s 1.5 m/s 0.5 m/s

A typical speed for a person
walking is 1.5 m/s.

Which equation is used to
summarise Newton's Second
Law?

force = mass x acceleration

What can you say about the forces on an object that is falling at its terminal velocity?

The resistive force acting
upwards equals the weight
acting downwards. The forces
are balanced and there is no
resultant force on the object.

List factors that will increase the braking distance of a vehicle.

higher vehicle speed; ice,
snow or water on the road;
poorly functioning brakes;
worn tyres; incorrectly
inflated tyres.

In the equation Ee = 1/2 ke^2 for calculating the elastic potential energy stored in a stretched spring, what does k represent and what is its unit?

k is the spring constant of the spring, which is a measure of its stiffness: force applied to spring = k x extension
The unit of k is N/m.

Complete this sentence correctly.
On a very cold day, a hut with thin metal walls
will cool down very quickly because of the metal's:
... low thermal conductivity
... high thermal conductivity

On a very cold day, a hut with
thin metal walls will cool
down very quickly because
of the metal's high thermal
conductivity.
The higher the thermal
conductivity of a material,
the higher the rate of energy
transfer by conduction
through the material.

What is the relationship between wave speed, wave frequency and wavelength?

wave speed = frequency x wavelength

Light travels across a boundary from a material
of high refractive index into air. Describe its change of direction.

The light changes direction
(is refracted) away from the
normal (the perpendicular
to the boundary) - unless
the light is travelling
perpendicular to the
boundary, in which case it
will continue straight.

Which type of electromagnetic
radiation correctly fills the gap in
these sentences? In an energy efficient lamp, .........
waves are produced by the gas inside
when an electric current passes. These
waves are absorbed by the coating on the lamp, which then gives off visible light.

Ultraviolet (UV)

What is the equation relating
the potential difference across,
the current through and the resistance of a component in a circuit?

Potential difference = current x resistance

State the behaviour of an LDR in
a circuit when the light intensity
falling on it decreases.

light-dependent resistor. Its electrical resistance increases when the light intensity decreases.

State the equation for calculating the
electrical power P of a device of resistance R, when the current through it is I, and state the unit of power.

Power P = I^2 R
The unit of power is the watt, W (equivalent to J/s).

State the colours of the wires in the cable of a
domestic appliance: the live wire, the neutral wire and the earth wire.

Live wire: brown
Neutral wire: blue
Earth wire: green and yellow (stripes)

True or false?
If all of the electrical
energy supplied to
an efficient kettle is used to
heat the water, this equation
determines the change in
temperature of the water,
∆θ. I V t = m c ∆θ

True.
The electrical energy supplied to
the kettle is power × time = I V t.
The rise in temperature of the
water ∆θ depends on the mass m
and the specific heat capacity c of the water. Energy change
of water = m c ∆θ.

Which of these
sentence endings
makes the statement
correct?
A magnetic material brought
close to a magnet ...
... is always attracted to the
N pole of the magnet.
... is attracted to the
nearest pole of the magnet.

A magnetic material brought
close to a magnet is attracted to
the nearest pole of the magnet.
The strong magnetic field near
either magnet pole makes the
nearby magnetic material an
induced magnet and this
always causes attraction.

List the factors that affect the size of the force on a current-carrying conductor in a magnetic field.

The magnetic flux density, the
size of the current and the
length of the conductor that is
in (and perpendicular to) the
magnetic field.

What is the difference between the
specific heat capacity and the specific latent heat of a material?

Specific heat capacity is the energy needed to raise the temperature of 1 kg of the material by 1 °C, with no change of state.
Specific latent heat is the energy
needed to change the state of
1 kg of the material, with no
change in temperature.

Choose the correct
word to complete
this sentence.
Isotopes of an element contain
the same number of ...
... neutrons ... protons

Isotopes of an element
contain the same number of
protons.
They have different numbers
of neutrons.

Complete the gaps in the sentences.
Choose from: greater smaller
more less
Beta radiation has a ... ionising
power than alpha radiation and
so is ... penetrating and has a ...
range in air.
A beta source a few metres away from you is therefore likely to be ... dangerous than an
alpha source at that distance.

Beta radiation has a smaller
ionising power than alpha
radiation and so is more
penetrating and has a greater
range in air.
A beta source a few metres
away from you is therefore
likely to be more dangerous
than an alpha source at that
distance.

State two definitions of
radioactive half-life.

1. The (average) time taken for half of the radioactive nuclei in a sample to decay.
2. The time taken for the activity (or count rate) of a radioactive
sample to fall to half its original value.