AQA GCSE COMBINED SCIENCE: TRILOGY
PRACTICE EXAMINATION 2026
QUESTIONS WITH ANSWERS GRADED A+
◍ What is an oxygen debt?.
Answer: The amount of extra oxygen your body needs to react with the
build up of lactic acid and remove it from the cells.
◍ Name three things that are re-absorbed by the kidneys into the blood..
Answer: Glucose, water and ions.
◍ Why can a farmer not just give a green house loads and loads of light and
heat?.
Answer: It may be more than the plant needs which wastes money.
◍ What are the advantages and disadvantages of a kidney transplant over
dialysis?.
Answer: Kidney transplants are a cure, but they can be rejected. Patients are
treated with immunosuppressants. People are not always on the donor list,
relatives have to agree to the donation. Transplants are cheaper than dialysis
to the NHS. Long waiting lists for transplants. Patients have to spend 3-4
hours a day, 3 x a week which can have a negative impact on their quality of
life.
◍ Name responses that reduce body temperature..
Answer: Hairs lie flat, sweat and blood vessels get wider(vasodilation)
◍ Describe the stages in a reflex arc..
Answer: Stimulus->Receptor->sensory neurone->CNS (relay neurone) ->
motor neurone -> effector -> response
◍ How many bases code for an amino acid?.
, Answer: Three/triplets
◍ What happens to increase respiration when you exercise?.
Answer: - Breathing rate increases.- Breath volume increases.- Heart rate
increases.
◍ What is the body's core temp?.
Answer: 37 degrees Celsius
◍ What effects chlorophyll concentration (limiting factor)?.
Answer: The amount of minerals in the soil.
◍ What do each of the chromosomes control?.
Answer: 22 pairs of chromosomes are matched/homologous pairs-control
CHARACTERISTICS23rd pair-XY or XX -Sex defining chromosomes
◍ Aside from tackling limiting factors, how are greenhouses ideal for plant
growth?.
Answer: - Easier to keep plants free from pests/diseases.- Can add fertilisers
to soil to provide all minerals needed.
◍ What is light intensity measured in?.
Answer: Arbitrary units.
◍ What effect does auxin have on shoots and roots?.
Answer: Auxin promotes growth in shoots and inhibits growth in roots.
◍ Prey.
Answer: Animals eaten by predators
◍ How could you investigate the effect of exercise on breathing and heart
rate?.
Answer: Take pulse and breathing rate after: - Sitting down for 5 mins. -
Walking for 5 mins. - Jogging for 5 mins. - Running for 5 mins.Plot results
in a bar chart
◍ What happens after the receptors?.
Answer: Receptors send messages to the CNS via the sensory neurone.
,◍ More pollution will be caused, unless....
Answer: ...waste and chemical materials and properly handled
◍ Give 3 examples of reactions in which larger molecules are made from
smaller ones:.
Answer: - Glucose molecules are joined together to make starch, glycogen
and cellulose.- Lipid molecules are made from one glycerol and three fatty
acids.- Glucose is combined with nitrate ions to form amino acids which
combine to form proteins.
◍ What are the main five ways that plant use glucose?.
Answer: 1) For respiration.2) Making cellulose, for strong plant cell walls.3)
Making amino acids, combined with nitrate ions.4) Stored as oils or fats in
seeds.5) Stored as starch, insoluble so better for storage
◍ Why is temperature usually a limiting factor of photosynthesis?.
Answer: It is normally too low which slows enzyme activity.
◍ What is the retina?.
Answer: Contains receptor cells called rods and cones. These are sensitive to
colour and light intensity.
◍ Give 2 examples of reactions is which larger molecules are broken down
into smaller ones:.
Answer: - Glucose is broken down in respiration.- Excess protein is broken
down to produce urea.
◍ What is respiration?.
Answer: A chemical reaction that releases energy from glucose which goes
on in every cell.
◍ Define accommodation..
Answer: Where the eye focuses light on the retina by changing the shape of
the lens.
◍ Name some of the treatments for vision defects..
Answer: Contact lenses, laser eye surgery and replacement lens surgery.
, ◍ Explain the Carl Woese three-domain system.
Answer: 1. Archaea-PRIMITIVE BACTIERIA often found in EXTREME
PLACES such as hot springs/salt lakes2.Bacteria-true bacteria(eg E
coli)-very biochemically different to Archaea3.Eukaryota-broad range of
organisms including fungi,plants,animals,protists.These are then subdivided
into smaller groups:-Kingdom, Phylum, Class, Order, Family, Genus,
Species
◍ How do you calculate efficiency of biomass transfer between trophic
levels?.
Answer: efficiency = biomass transferred to next level/biomass available at
previous level x 100
◍ Median.
Answer: The middle value of the range
◍ What is fermentation used for?.
Answer: Making bread - CO2 makes bread riseMaking wine and beer -
Ethanol.
◍ What happens after resorting to anaerobic respiration when you stop
exercising?.
Answer: You have an oxygen debt.
◍ What is cystic fibrosis?.
Answer: It is a genetic disorder of the cell membranes. Causes thick, sticky
mucus to build up in air passages and pancreas.
◍ How did the discovery of genetics support Darwin's theory?.
Answer: It explained WHY NEW characteristics appeared or how organisms
passed on their beneficial adaptations.
◍ What is anaerobic respiration?.
Answer: The incomplete breakdown of glucose producing lactic acid.
◍ Give 3 examples of how organisms use the energy they gain from
respiration:.
PRACTICE EXAMINATION 2026
QUESTIONS WITH ANSWERS GRADED A+
◍ What is an oxygen debt?.
Answer: The amount of extra oxygen your body needs to react with the
build up of lactic acid and remove it from the cells.
◍ Name three things that are re-absorbed by the kidneys into the blood..
Answer: Glucose, water and ions.
◍ Why can a farmer not just give a green house loads and loads of light and
heat?.
Answer: It may be more than the plant needs which wastes money.
◍ What are the advantages and disadvantages of a kidney transplant over
dialysis?.
Answer: Kidney transplants are a cure, but they can be rejected. Patients are
treated with immunosuppressants. People are not always on the donor list,
relatives have to agree to the donation. Transplants are cheaper than dialysis
to the NHS. Long waiting lists for transplants. Patients have to spend 3-4
hours a day, 3 x a week which can have a negative impact on their quality of
life.
◍ Name responses that reduce body temperature..
Answer: Hairs lie flat, sweat and blood vessels get wider(vasodilation)
◍ Describe the stages in a reflex arc..
Answer: Stimulus->Receptor->sensory neurone->CNS (relay neurone) ->
motor neurone -> effector -> response
◍ How many bases code for an amino acid?.
, Answer: Three/triplets
◍ What happens to increase respiration when you exercise?.
Answer: - Breathing rate increases.- Breath volume increases.- Heart rate
increases.
◍ What is the body's core temp?.
Answer: 37 degrees Celsius
◍ What effects chlorophyll concentration (limiting factor)?.
Answer: The amount of minerals in the soil.
◍ What do each of the chromosomes control?.
Answer: 22 pairs of chromosomes are matched/homologous pairs-control
CHARACTERISTICS23rd pair-XY or XX -Sex defining chromosomes
◍ Aside from tackling limiting factors, how are greenhouses ideal for plant
growth?.
Answer: - Easier to keep plants free from pests/diseases.- Can add fertilisers
to soil to provide all minerals needed.
◍ What is light intensity measured in?.
Answer: Arbitrary units.
◍ What effect does auxin have on shoots and roots?.
Answer: Auxin promotes growth in shoots and inhibits growth in roots.
◍ Prey.
Answer: Animals eaten by predators
◍ How could you investigate the effect of exercise on breathing and heart
rate?.
Answer: Take pulse and breathing rate after: - Sitting down for 5 mins. -
Walking for 5 mins. - Jogging for 5 mins. - Running for 5 mins.Plot results
in a bar chart
◍ What happens after the receptors?.
Answer: Receptors send messages to the CNS via the sensory neurone.
,◍ More pollution will be caused, unless....
Answer: ...waste and chemical materials and properly handled
◍ Give 3 examples of reactions in which larger molecules are made from
smaller ones:.
Answer: - Glucose molecules are joined together to make starch, glycogen
and cellulose.- Lipid molecules are made from one glycerol and three fatty
acids.- Glucose is combined with nitrate ions to form amino acids which
combine to form proteins.
◍ What are the main five ways that plant use glucose?.
Answer: 1) For respiration.2) Making cellulose, for strong plant cell walls.3)
Making amino acids, combined with nitrate ions.4) Stored as oils or fats in
seeds.5) Stored as starch, insoluble so better for storage
◍ Why is temperature usually a limiting factor of photosynthesis?.
Answer: It is normally too low which slows enzyme activity.
◍ What is the retina?.
Answer: Contains receptor cells called rods and cones. These are sensitive to
colour and light intensity.
◍ Give 2 examples of reactions is which larger molecules are broken down
into smaller ones:.
Answer: - Glucose is broken down in respiration.- Excess protein is broken
down to produce urea.
◍ What is respiration?.
Answer: A chemical reaction that releases energy from glucose which goes
on in every cell.
◍ Define accommodation..
Answer: Where the eye focuses light on the retina by changing the shape of
the lens.
◍ Name some of the treatments for vision defects..
Answer: Contact lenses, laser eye surgery and replacement lens surgery.
, ◍ Explain the Carl Woese three-domain system.
Answer: 1. Archaea-PRIMITIVE BACTIERIA often found in EXTREME
PLACES such as hot springs/salt lakes2.Bacteria-true bacteria(eg E
coli)-very biochemically different to Archaea3.Eukaryota-broad range of
organisms including fungi,plants,animals,protists.These are then subdivided
into smaller groups:-Kingdom, Phylum, Class, Order, Family, Genus,
Species
◍ How do you calculate efficiency of biomass transfer between trophic
levels?.
Answer: efficiency = biomass transferred to next level/biomass available at
previous level x 100
◍ Median.
Answer: The middle value of the range
◍ What is fermentation used for?.
Answer: Making bread - CO2 makes bread riseMaking wine and beer -
Ethanol.
◍ What happens after resorting to anaerobic respiration when you stop
exercising?.
Answer: You have an oxygen debt.
◍ What is cystic fibrosis?.
Answer: It is a genetic disorder of the cell membranes. Causes thick, sticky
mucus to build up in air passages and pancreas.
◍ How did the discovery of genetics support Darwin's theory?.
Answer: It explained WHY NEW characteristics appeared or how organisms
passed on their beneficial adaptations.
◍ What is anaerobic respiration?.
Answer: The incomplete breakdown of glucose producing lactic acid.
◍ Give 3 examples of how organisms use the energy they gain from
respiration:.
