IGCSE Science - Combined (0653) — May–June 2023, Paper 21

Which characteristic of living organisms involves chemical reactions in cells that break down nutrient molecules and release energy? A excretion B nutrition C respiration D…

Which structures are present in an animal cell? cell membrane cell wall cytoplasm nucleus --- --- --- --- --- A ✓ ✗ ✓ ✓ B ✓ ✓ ✗ ✓ C ✓ ✗ ✗ ✓ D ✗ ✓ ✓ ✗ key: ✓ = present, ✗ = not…

Which row describes the movement of water by osmosis? from a region of to a region of through A low water potential high water potential a partially permeable membrane B low water…

Which combination of pH and temperature does not denature a protease enzyme from the stomach? temperature pH / °C A 3 37 B 3 60 C 10 37 D 10 60

Four test-tubes are set up as shown. In which test-tube is there an increase in oxygen concentration after 4 hours? A B C D black polythene to keep water out light light light…

What is the purpose of chemical digestion? A to absorb minerals including calcium and iron B to pass food out as faeces C to break down large nutrient molecules into smaller…

Which row matches the adaptation of a root hair cell to its function? adaptation function A large surface area uptake of water and glucose B large surface area uptake of water and…

The diagram shows a section through the heart. Which vessel is the pulmonary vein? D A B C

Which molecule contains the energy that is released in aerobic respiration? A C6H12O6 B CO2 C H2O D O2

What are features of sexual reproduction? fusion nature of offspring of nuclei A no genetically different B yes genetically identical C no genetically identical D yes genetically…

The diagrams show four different flowers. 1 2 3 4 Which flowers are wind pollinated? A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

Which letter represents the secondary consumer in the food chain shown? A B C D

The flow chart shows some of the steps in the process of eutrophication. increased availability of nitrates and other ions ↓ step X ↓ increased decomposition after death of…

Which diagram represents particles in a gaseous element? A B C D

What is the relative mass of a proton and the relative charge on a proton? relative mass relative charge A 0.0005 +1 B 0.0005 –1 C 1 –1 D 1 +1

Sodium reacts with chlorine to form sodium chloride. Which statement describes a change that occurs during this reaction? A Each chlorine atom loses one proton. B Each sodium atom…

Sodium burns in oxygen forming sodium oxide. An equation for this reaction is shown. xNa + yO2 → zNa2O What are x, y and z? x y z A 2 1 2 B 2 2 1 C 4 1 2 D 4 2 2

Which statement about the electrolysis of molten lead(II) bromide is correct? A Lead anions move to the anode where they gain electrons. B Lead anions move to the cathode where…

Which process is endothermic? A the reaction of petrol with air in a car engine B Cl –Cl → Cl + Cl C the reaction of potassium with water D C + O2 → CO2

The equation for the reaction of zinc oxide with carbon monoxide is shown. ZnO + CO → Zn + CO2 Which statement explains the role of carbon monoxide in this reaction? A It is the…

Dilute hydrochloric acid is tested with universal indicator and with calcium carbonate. Which row shows the pH and describes the reaction with calcium carbonate? pH reaction with…

The results of two tests on a solution of substance R are shown. test result aqueous sodium red-brown precipitate formed, hydroxide added insoluble in excess dilute nitric acid…

The character of the elements changes from metallic to non-metallic across a period of the Periodic Table. Which statement explains this change? A Metal atoms need to gain…

Copper oxide and excess carbon are mixed together. The mass before heating is 12.2 g. The mixture is heated strongly and allowed to cool. The mass after heating is 10.4 g. Why…

Which statement about both carbon dioxide and methane is correct? A Increased concentrations of carbon dioxide and methane in the air cause an enhanced greenhouse effect. B…

Why are alkanes members of the same homologous series? A They are all hydrocarbons. B They have similar physical properties. C They have the same general formula. D They all…

What are the products of cracking large alkane molecules? A smaller alkanes only B smaller alkenes only C smaller alkanes, alkenes and hydrogen D smaller alkanes and hydrogen only

The graph shows the motion of a cyclist over a period of 30 s. speed m/s 0 20 30 time / s Which distance does the cyclist travel? A 90 m B 105 m C 115 m D 120 m

A solid cuboid block of metal has density ρ. The diagram shows its dimensions. y x z Which expression is used to calculate the mass of the block? ρ ρ A B C ρxy D ρxyz xy xyz

A spring that obeys Hooke’s law is fixed at one end. When the spring is pulled by a force of 30 N, it has a stretched length of 14 cm. When the spring is pulled by a force of 48…

A 3.0 kW electric kettle is switched on for 30 seconds. Which row gives the equation that defines power and gives the energy transferred in the kettle? equation energy / J A P =…

Solar cells mounted on a boat produce electrical energy to power the motor. solar cells Which resource does this energy come from? A hydroelectric energy B light energy C tidal…

The molecules in a liquid are close together. What are other features of the molecules in a liquid? A They are arranged in a regular pattern but change positions with each other.…

What is a method of thermal conduction in a metal? A electrons moving through the metal, hitting distant molecules B electrons vibrating and passing on energy to other electrons C…

The diagram represents a wave in air. Molecules are closer together in region P than they are in region Q. region P region Q What are the names of regions P and Q, and which type…

The diagram shows an object placed at position O near a thin converging lens. F1 and F2 are the principal focuses of the lens. A student draws four rays that leave the top of the…

The unit of electric charge is the coulomb (C). Which combination of other units is equivalent to the coulomb? A A/s B As C V/A D VA

Which circuit is used to determine the resistance of resistor R? A B R R A A V V C D R V V R A A

Which arrangement of resistors has the smallest combined resistance? A B 2.0 : 3.0 : 4.0 : 2.0 : 3.0 : 4.0 : C D 2.0 : 3.0 : 2.0 : 3.0 : 4.0 : 4.0 :

The diagram shows two resistors connected in parallel to a battery. Currents I1 and I2 are labelled. Current I1 is greater than current I2. I1 I2 Which calculation gives the…