GCSE Combined Science Foundation Paper 2
Covers Cell Biology, Organisation, Infection and Response and 9 more.
Questions
Question 1 [2 marks]
Forces
Newton's Third Law of Motion describes the forces that act between two interacting objects.
State Newton's Third Law of Motion.
Question 2 [2 marks]
Organisation
Amylase and protease are two enzymes involved in human digestion.
State the function of amylase and the function of protease in digestion.
Question 3 [2 marks]
Electricity
Ohm's law relates the potential difference, current and resistance in a circuit.
Write down the equation linking potential difference (V), current (I) and resistance (R).
State the unit of electrical resistance.
Question 4 [3 marks]
Energy
A car of mass 1200 kg travels at a speed of 15 m/s.
Calculate the kinetic energy of the car. Use KE = 1/2 m v^2.
Question 5 [3 marks]
Cell Biology
A plant cell contains a cell wall, a chloroplast and a permanent vacuole in addition to the structures found in an animal cell.
Describe the function of the cell wall, the chloroplast and the permanent vacuole in a plant cell.
Question 6 [3 marks]
Bonding, Structure and the Properties of Matter
An alloy is a mixture of a metal with one or more other elements.
Describe what an alloy is, and explain why alloys are usually harder than the pure metal they are made from.
Question 7 [3 marks]
Chemical Changes
A student collects a gas produced in a reaction and wants to test whether it is hydrogen.
Describe how the student would test the gas to show it is hydrogen, and state the expected result.
Question 8 [4 marks]
Atomic Structure and the Periodic Table
Following the nuclear model of the atom, scientists further developed our understanding of atomic structure.
Describe how Niels Bohr adapted the nuclear model of the atom, and describe the later discovery that showed the positive charge of the nucleus is made up of smaller particles.
Question 9 [4 marks]
Electricity
A resistor at constant temperature and a filament lamp are both circuit components whose resistance can be investigated.
Describe how the resistance of a resistor at constant temperature changes as the current through it increases, and describe how the resistance of a filament lamp changes as the current through it increases.
Question 10 [4 marks]
Atomic Structure and the Periodic Table
Chlorine has two naturally occurring isotopes: chlorine-35, with an abundance of 75%, and chlorine-37, with an abundance of 25%.
Calculate the relative atomic mass of chlorine. Give your answer to 1 decimal place.
Question 11 [5 marks]
Infection and Response
In a culture, the number of a certain virus doubles every 30 minutes.
A sample starts with 200 virus particles.
Calculate the number of virus particles present after 2.5 hours.
Question 12 [5 marks]
Particle Model of Matter
Substances can exist as a solid, a liquid or a gas.
Describe, in terms of particles, the arrangement, movement and energy of particles in a solid, and describe what happens to the particles when the solid is heated until it melts.
Question 13 [5 marks]
Bioenergetics
A student investigates the rate of photosynthesis in pondweed by counting bubbles of oxygen released.
At a light intensity of 400 lux, 45 bubbles are released in 3 minutes.
At a higher light intensity, 75 bubbles are released in the same time.
Calculate the percentage increase in the rate of bubble production caused by the higher light intensity. Give your answer to 1 decimal place.
Question 14 [5 marks]
Quantitative Chemistry
A student dissolves 6.0 g of potassium chloride in water to make 250 cm^3 of solution.
Calculate the concentration of the potassium chloride solution, in g/dm^3.
Question 15 [5 marks]
Infection and Response
A student wants to grow a culture of bacteria on an agar plate to investigate the effect of an antibiotic.
Describe the aseptic techniques the student should use to prevent contamination of the culture by unwanted microorganisms.
Question 16 [5 marks]
Cell Biology
An enzyme-controlled reaction is carried out at a range of temperatures from 10 degrees C to 60 degrees C. The enzyme's optimum temperature is 37 degrees C.
Describe and explain how the rate of this enzyme-controlled reaction changes as the temperature increases from 10 degrees C to 60 degrees C.
Model solutions
| Question 1[2 marks] | |
|---|---|
| Answer or working | Marks |
| stating that when two objects interact, they exert forces on each other that are equal in size | B1 |
| stating that these forces act in opposite directions, one on each object | B1 |
| Final answer: When two objects interact, they exert equal and opposite forces on each other | |
| Question 2[2 marks] | |
|---|---|
| Answer or working | Marks |
| amylase breaking down starch into sugars | B1 |
| protease breaking down proteins into amino acids | B1 |
| Final answer: Amylase breaks down starch into sugars; protease breaks down proteins into amino acids | |
| Question 3[2 marks] | |
|---|---|
| Answer or working | Marks |
| V = I R | B1 |
| the unit of resistance being the ohm | B1 |
| Final answer: V = I R; ohm | |
| Question 4[3 marks] | |
|---|---|
| Answer or working | Marks |
| substituting into KE = 1/2 m v^2 | M1 |
| 15^2 = 225 | M1 |
| 135000 J (135 kJ) | A1 |
| Question 5[3 marks] | |
|---|---|
| Answer or working | Marks |
| the cell wall, made of cellulose, supporting and strengthening the cell | B1 |
| the chloroplast absorbing light energy to carry out photosynthesis | B1 |
| the permanent vacuole containing cell sap, helping to keep the cell rigid (turgid) | B1 |
| Final answer: Cell wall supports and strengthens the cell; chloroplast absorbs light for photosynthesis; vacuole contains cell sap and keeps the cell turgid | |
| Question 6[3 marks] | |
|---|---|
| Answer or working | Marks |
| an alloy being a mixture of a metal with one or more other elements | B1 |
| the different-sized atoms in an alloy distorting the regular layers of metal ions | B1 |
| this making it harder for the layers to slide over each other, so alloys are harder than the pure metal | B1 |
| Final answer: An alloy is a metal mixed with other elements; different-sized atoms distort the layers, making it harder for them to slide, so alloys are harder | |
| Question 7[3 marks] | |
|---|---|
| Answer or working | Marks |
| holding a lighted splint at the open end of the test tube | B1 |
| the gas igniting/burning rapidly | B1 |
| a squeaky pop sound, confirming hydrogen gas | B1 |
| Final answer: Squeaky pop with a lighted splint | |
| Question 8[4 marks] | |
|---|---|
| Answer or working | Marks |
| Bohr proposing that electrons orbit the nucleus at specific, fixed distances (in shells or energy levels) | B1 |
| stating this model agreed with experimental observations, unlike a nucleus with electrons able to orbit at any distance | B1 |
| later experimental work showing the positive charge of the nucleus could be divided into smaller particles | B1 |
| these particles being identified as protons, each with a relative charge of +1 | B1 |
| Final answer: Bohr proposed electrons orbit in fixed shells; later work showed the nucleus's positive charge is made up of protons, each with a +1 charge | |
| Question 9[4 marks] | |
|---|---|
| Answer or working | Marks |
| the resistance of a resistor at constant temperature staying constant as the current changes | B1 |
| the resistance of a filament lamp increasing as the current through it increases | B1 |
| stating this is because the temperature of the filament increases as more current flows | B1 |
| stating the resistance of a metal increases as its temperature increases, making it harder for the charge carriers to pass through | B1 |
| Final answer: A resistor's resistance stays constant with current; a filament lamp's resistance increases with current, because it heats up and a hotter metal has higher resistance | |
| Question 10[4 marks] | |
|---|---|
| Answer or working | Marks |
| multiplying each isotope's mass by its percentage abundance | M1 |
| (35 x 75) + (37 x 25) | M1 |
| dividing the total by 100 | M1 |
| 35.5 | A1 |
| Question 11[5 marks] | |
|---|---|
| Answer or working | Marks |
| converting 2.5 hours to minutes, 2.5 x 60 = 150 minutes | M1 |
| finding the number of doublings, 150 / 30 = 5 | M1 |
| using 2 raised to the power of the number of doublings, 2^5 = 32 | M1 |
| multiplying the starting number by this, 200 x 32 | M1 |
| 6400 virus particles | A1 |
| Question 12[5 marks] | |
|---|---|
| Answer or working | Marks |
| particles in a solid being arranged in a regular, closely packed pattern | B1 |
| particles in a solid vibrating about a fixed position | B1 |
| there being strong forces of attraction between particles in a solid | B1 |
| heating giving particles more (kinetic) energy, so they vibrate more | B1 |
| particles gaining enough energy to overcome the forces holding them in place and move around each other (melting) | B1 |
| Final answer: Solid particles are closely packed and vibrate in place; heating gives them enough energy to overcome attractive forces and melt | |
| Question 13[5 marks] | |
|---|---|
| Answer or working | Marks |
| finding the rate at the lower light intensity, 45 / 3 = 15 bubbles per minute | M1 |
| finding the rate at the higher light intensity, 75 / 3 = 25 bubbles per minute | M1 |
| finding the increase in rate, 25 - 15 = 10 | M1 |
| (10 / 15) x 100 | M1 |
| 66.7% | A1 |
| Final answer: 66.7% increase in the rate of bubble production | |
| Question 14[5 marks] | |
|---|---|
| Answer or working | Marks |
| converting the volume to dm^3, 250 / 1000 | M1 |
| 0.25 dm^3 | A1 |
| using concentration = mass / volume | M1 |
| substituting 6.0 / 0.25 | M1 |
| 24 g/dm^3 | A1 |
| Question 15[5 marks] | |
|---|---|
| Answer or working | Marks |
| sterilising the agar plates and culture media before use, to kill unwanted microorganisms | B1 |
| sterilising the inoculating loop by passing it through a flame before and after use | B1 |
| briefly lifting (rather than fully removing) the lid of the petri dish when inoculating, to reduce contamination from the air | B1 |
| taping the lid of the petri dish closed after inoculating | B1 |
| incubating the plate at a suitable temperature, below 25 degrees C in a school laboratory, to reduce the growth of harmful pathogens | B1 |
| Final answer: Sterilise the plates, media and inoculating loop, briefly lift (not remove) the lid when inoculating, tape the lid shut, and incubate below 25 degrees C in a school lab | |
| Question 16[5 marks] | |
|---|---|
| Answer or working | Marks |
| the rate of reaction increasing as temperature increases from 10 degrees C towards 37 degrees C | B1 |
| this being because the enzyme and substrate particles have more kinetic energy and collide more frequently | B1 |
| the rate being at its maximum at the optimum temperature, 37 degrees C | B1 |
| the rate decreasing rapidly above 37 degrees C because the enzyme becomes denatured | B1 |
| stating that denaturing changes the shape of the enzyme's active site, so the substrate no longer fits and the enzyme stops working | B1 |
| Final answer: Rate increases up to the optimum at 37 degrees C as collisions increase, then falls rapidly as the enzyme denatures and its active site changes shape | |