WJEC GCSE Integrated Science (Single Award) Revision

High temperature can denature the active site so starch no longer fits. Cold normally reduces the rate without permanently changing the active site.

The portions may be different sizes. Compare like masses, then calculate the nutrients and energy in the actual portion.

Breathing ventilates the lungs; respiration consists of reactions in cells that transfer energy from substances such as glucose.

Glucose is not fully broken down; energy remains in lactic acid, so less energy is transferred through ATP than in aerobic respiration.

The heart muscle itself needs its own oxygen and nutrient supply from coronary vessels; chamber blood does not directly supply every muscle cell.

No. Flat distance-time means stationary; flat speed-time means constant speed, which may be non-zero.

Gradient divides m/s by s to give m/s²; area multiplies m/s by s to give metres.

Other genetic, environmental or lifestyle variables may affect both, so further controlled and converging evidence is needed.

Mucus traps particles and microorganisms, and cilia move the mucus towards removal from the respiratory tract.

Memory cells formed after the first infection or vaccination recognise the antigen and support rapid antibody production.

Calcium chloride, with water and carbon dioxide; the chloride ending comes from hydrochloric acid.

Its source, date, supporting evidence, relevant population, actual risk size and limitations, rather than the headline or social approval alone.

Its kinetic-store energy is transferred mainly into thermal stores of brakes, tyres, road and surroundings; it is not destroyed.

It builds organic food from carbon dioxide and water, supplies oxygen and removes carbon dioxide that can later return through respiration or decomposition.

Another factor, such as insufficient light, may still be limiting the rate.

Some material is uneaten or undigested, and respiration transfers energy to thermal stores rather than all energy becoming the next level's biomass.

Some energy heats the container and surroundings, combustion may be incomplete and fuel may evaporate, so the water receives only part of the transferred energy.

It releases gravitational-store energy supplied earlier when water was pumped uphill, with some energy lost to less useful transfers.

No. It separates existing molecules by boiling behaviour; breaking molecules into smaller ones is a chemical process, not distillation.

Zinc is more reactive, so it forms zinc sulfate while copper is produced.

Reactants are being used up, reducing the rate; a flat cumulative gas-volume curve means no further measured gas is being produced.

It exposes more surface sites to reacting particles, increasing opportunities for successful collisions without changing the total solid mass.

Producing, compressing and transporting hydrogen may use energy from carbon-emitting sources, even though its combustion product is water.

kW multiplied by hours gives kWh; using seconds without conversion gives a different unit and an incorrect numerical bill.

No. It was transferred to stores not useful for the device's intended purpose, such as thermal stores of the surroundings.

Thinking time and therefore thinking distance; overall stopping distance increases even if braking conditions are unchanged.

Its patch may not represent the habitat. A suitable sampling strategy, several samples and a consistent area/counting method reduce sampling bias.

Its production may have a higher initial impact, which must be compared across enough equivalent uses, including cleaning, transport and disposal.

They have different warming potentials; convert each mass using the given GWP to a common CO₂-equivalent basis.

Less incoming energy is reflected, more is absorbed by darker surfaces, and the resulting warming can melt further ice.

No. Their mass remains 60 kg; weight changes because the Moon's gravitational field strength is different.

Upward drag balances downward weight, so the resultant and acceleration are zero even though the object is moving.

T complements A, and G complements C.

Different triplets can encode the same amino acid; the result must be checked against the supplied coding information.

The main asteroid belt is between Mars and Jupiter; the Kuiper belt is beyond Neptune.

Packaging helps prevent moisture uptake and contamination, maintaining the conditions that limit microbial growth.

The mission needs a continuing safe and nutritionally adequate supply despite storage limits, failures and possible resupply delays.

Plants need appropriate mineral nutrients, oxygen at roots and controlled conditions including pH, light and temperature.

The components have different requirements: heat resistance alone does not provide transparency, strength or the other necessary properties.

No. Crest-to-trough displacement is 4 cm; amplitude is measured from equilibrium.

No. Sound needs a medium; electromagnetic signals can carry encoded speech through the vacuum.

It is above the atmosphere that absorbs some wavelengths, although its own detectors and design still limit what it can observe.

It adds chloride ions itself, potentially creating the precipitate even if the original sample did not contain chloride.

Green suggests iron(II); brown suggests iron(III), using the specified sodium-hydroxide test.

Benedict's detects reducing sugars, so other reducing sugars can also give a positive result.

Genetic information can reveal relationships and information relevant to relatives, alongside the donor's own privacy and possible misuse.

The increase is the sample's displaced volume; the final reading also includes the water already present.

Yes. They can be precise but systematically shifted from the true value; additional repeats alone do not remove that offset.

The equation requires radius, so r is 3 cm. Using 6 cm gives an area four times too large.

The line does not pass through the origin; use differences, (14−2)/(4−0)=3.

No. Unit 3 is a separate official external enquiry assessment; this guidance is non-counting.