Science Assessment- Task 2, 2026

What is a disease?

A condition that disrupts normal body function.

What is a pathogen?

A disease-causing microorganism or infectious agent.

What is an infectious disease?

A disease caused by a pathogen that can spread between organisms.

What is a non-infectious disease?

A disease that is not caused by a pathogen and cannot spread between people.

Give examples of infectious diseases.

Influenza, COVID-19, measles and malaria.

Give examples of non-infectious diseases.

Cancer, diabetes, asthma and cardiovascular disease.

What causes infectious diseases?

Pathogens such as viruses, bacteria, fungi, protozoa and parasites.

What causes non-infectious diseases?

Genetics, lifestyle, environmental factors and ageing.

How are infectious diseases transmitted?

Through air, droplets, direct contact, contaminated food/water, vectors or body fluids.

What is a virus?

A pathogen that reproduces inside living host cells.

What is a bacterium?

A single-celled microorganism; some species cause disease.

What is a fungus?

An organism that can cause infections such as athlete's foot.

What is a protozoan?

A microscopic single-celled organism; some cause diseases such as malaria.

What is a parasite?

An organism that lives on or in a host and obtains resources from it.

What is an epidemic?

A disease outbreak affecting more people than normally expected in a region.

What is an endemic disease?

A disease that is consistently present in a particular region or population.

What is a pandemic?

An infectious disease outbreak that spreads across many countries or continents.

What is an antigen?

A foreign substance that triggers an immune response.

What is an antibody?

A protein made by immune cells that specifically binds to an antigen.

What is the first line of defence?

Physical and chemical barriers that prevent pathogens entering the body.

Give examples of first-line defences.

Skin, mucus, cilia, tears, saliva and stomach acid.

What is the second line of defence?

Non-specific internal defences that attack pathogens after entry.

Give examples of second-line defences.

Inflammation, fever and white blood cells that engulf pathogens.

What is the third line of defence?

A specific immune response involving lymphocytes, antibodies and immune memory.

What do white blood cells do?

Recognise, attack and destroy pathogens or infected cells.

How does the skin prevent infection?

It forms a physical barrier preventing pathogens from entering the body.

How does mucus protect the body?

It traps pathogens so they can be removed.

How do cilia protect the respiratory system?

They move mucus and trapped pathogens towards the throat.

How does stomach acid defend against pathogens?

Its low pH destroys many pathogens swallowed with food.

What is vaccination?

Introducing harmless pathogen material to stimulate immunity.

How does vaccination produce immunity?

It stimulates the body to produce specific antibodies and memory cells.

Why are memory cells important?

They allow a faster, stronger immune response during future infections.

What is immunisation?

The process of becoming protected against a disease, often through vaccination.

How can immunisation reduce disease spread?

Fewer susceptible people means pathogens have fewer opportunities to spread.

What is a neuron?

A specialised cell that transmits electrical signals through the nervous system.

What is the function of dendrites?

They receive signals from other neurons or receptors.

What is the function of the cell body?

It contains the nucleus and controls the neuron's activities.

What is the function of the axon?

It carries electrical impulses away from the cell body.

What is the function of the myelin sheath?

It insulates the axon and increases signal transmission speed.

What are axon terminals?

Structures that pass signals to another neuron or effector.

How does a neuron transmit information?

Electrical impulses travel along the neuron and chemical signals cross synapses.

What is a synapse?

The small junction between neurons where neurotransmitters carry signals.

What is a finite resource?

A resource available in limited amounts that can be depleted.

What is a renewable resource?

A resource naturally replenished at a rate comparable to its use.

Give examples of finite resources.

Coal, oil, natural gas and many mineral ores.

Give examples of renewable resources.

Solar, wind, hydroelectric, geothermal and sustainably managed biomass.

Why are finite resources not sustainable?

They form slowly and can be used faster than they are replaced.

What is atomic number?

The number of protons in an atom's nucleus.

What is mass number?

The total number of protons and neutrons in an atom.

How do you calculate neutrons?

Neutrons = mass number − atomic number.

How many electrons does a neutral atom have?

The same number of electrons as protons.

What is an ion?

An atom or group of atoms with an overall electrical charge.

What is a cation?

A positively charged ion formed when electrons are lost.

What is an anion?

A negatively charged ion formed when electrons are gained.

What happens when an atom becomes a cation?

It loses one or more electrons.

What happens when an atom becomes an anion?

It gains one or more electrons.

What is ionic bonding?

Electrostatic attraction between oppositely charged ions.

How are ionic compounds formed?

Usually when electrons transfer from a metal to a non-metal.

What is covalent bonding?

The sharing of electron pairs between atoms.

What elements usually form covalent compounds?

Non-metals bonded to other non-metals.

What is metallic bonding?

Attraction between positive metal ions and delocalised electrons.

What are delocalised electrons?

Valence electrons that move freely throughout a metal lattice.

What are diatomic molecules?

Molecules made from two atoms of the same element.

Which elements commonly exist as diatomic molecules?

H₂, N₂, O₂, F₂, Cl₂, Br₂ and I₂.

What is nitrate?

A polyatomic ion with the formula NO₃⁻.

What is the formula for sodium nitrate?

NaNO₃.

What is the formula for calcium nitrate?

Ca(NO₃)₂.

What is the formula for aluminium nitrate?

Al(NO₃)₃.

What is the name of NaCl?

Sodium chloride.

What is the name of MgO?

Magnesium oxide.

What is the name of Ca(NO₃)₂?

Calcium nitrate.

What is the name of Al₂O₃?

Aluminium oxide.

How are ionic compounds named?

Name the metal first, then the non-metal with an -ide ending, or polyatomic ion name.

What are the properties of ionic compounds?

High melting points; usually brittle; conduct electricity when molten or dissolved.

Why do ionic compounds conduct when molten or dissolved?

Their ions are free to move and carry electrical charge.

What are the properties of covalent molecular substances?

Usually low melting/boiling points and poor electrical conductivity.

Why do covalent molecular substances have low melting points?

Weak intermolecular forces hold their molecules together.

What are the properties of metals?

Strong, malleable, ductile and good conductors of heat and electricity.

Why are metals good electrical conductors?

Their delocalised electrons can move through the structure.

What is crude oil?

A mixture of hydrocarbons formed from ancient organic matter.

How is crude oil separated?

By fractional distillation based on different boiling points.

What is fractional distillation?

A process separating crude oil into fractions with different boiling ranges.

What are fractions?

Groups of hydrocarbons with similar boiling points and properties.

What are common uses of crude oil fractions?

Fuels, lubricants, solvents, plastics and chemical manufacture.

What is a hydrocarbon?

A compound containing only carbon and hydrogen.

What is IUPAC nomenclature?

A standard system for naming chemical compounds.

What is an alkane?

A saturated hydrocarbon containing only single C–C bonds.

What is the general formula for alkanes?

CₙH₂ₙ₊₂.

What is methane's formula?

CH₄.

What is ethane's formula?

C₂H₆.

What is propane's formula?

C₃H₈.

What is butane's formula?

C₄H₁₀.

What is pentane's formula?

C₅H₁₂.

What is hexane's formula?

C₆H₁₄.

What is heptane's formula?

C₇H₁₆.

What is octane's formula?

C₈H₁₈.

What is the structure of methane?

One carbon bonded to four hydrogen atoms.

What is the structure of ethane?

CH₃–CH₃.

What is the structure of propane?

CH₃–CH₂–CH₃.

What is the structure of butane?

CH₃–CH₂–CH₂–CH₃.