AQA 9-1 Combined Science Trilogy GCSE

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,