(6) (total 9 marks) - wikispacestavistockcollegescience.wikispaces.com/file/view/core+science... ·...

Q1. Medical scientists research microbes and the diseases they cause.

An important part of this research is identifying what type of microbe causes which disease.

(a) Many diseases in humans are caused by bacteria and viruses.

Tick ( ) the correct box in the table for each disease to show if the disease is caused by bacteria or viruses.

(3)

Disease Caused by bacteria Caused by viruses

Influenza

Mumps

Cholera

Tuberculosis

(b) In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate.

Describe how vaccination helps people to develop immunity to a disease.

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(Total 9 marks)

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Q2. (a) (i) Some diseases can be tackled by using antibiotics and vaccination. Explain fully why antibiotics cannot be used to cure viral diseases.

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(ii) A recent study found that babies in 90 % of hospitals are infected with the MRSA bacterium.

Explain how the MRSA bacterium has developed resistance to antibiotics.

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(b) A person can be immunised against a disease by injecting them with an inactive form of a pathogen.

Explain how this makes the person immune to the disease.

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(Total 7 marks)

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Q3. An investigator placed paper discs containing different concentrations of an antibiotic onto a culture of bacteria in a petri dish.

After an incubation period of two days, the dish looked like this.

(a) Explain why there are areas around some of the paper discs where no bacteria are growing.

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(b) The concentration of the antibiotic on the paper discs is given in the table, along with the diameter of the circles where no bacteria are growing.

What effect does an increase in the concentration of the antibiotic have on the growth of the bacteria?

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Disc Concentration of the antibiotic in units

Diameter of circle where no bacteria are growing, in mm

A 0 0

B 2 8

C 4 14

D 6 26

E 10 26

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(c) When students carry out this experiment, they need to take several safety precautions.

The precautions include:

• passing inoculating loops through a flame

• sealing the lid of the petri dish with tape

• incubating at a maximum temperature of 25 °C.

Explain why each of these precautions is necessary.

To gain full marks in this question you should write your ideas in good English. Put them into a sensible order and use the correct scientific word.

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(d) Scientists are concerned that many bacteria are developing resistance to antibiotics.

Suggest two ways by which this problem could be limited.

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(Total 11 marks)

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Q4. Read the passage about antibiotics.

(a) To gain full marks for this question you should write your ideas in good English. Put them into a sensible order and use the correct scientific words.

Explain how a population of antibiotic-resistant bacteria might develop from non-resistant bacteria.

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People do not always agree about the use of antibiotics in food production.

If we put low doses of antibiotics in feed for animals such as cattle and sheep, it helps to produce high-quality, low-cost food. Antibiotics help to keep animals disease-free. They also help animals to grow. Animals get fatter quicker because they do not waste energy trying to overcome illness.

The use of antibiotics in livestock feed means that there is a higher risk of antibiotic-resistant bacteria developing. The rapid reproduction of bacteria means there is always a chance that a population of bacteria will develop which is antibiotic-resistant. These could be dangerous to human health.

(b) Do you think that farmers should be allowed to put low doses of antibiotics in animal feed? Explain the reasons for your answer.

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(Total 5 marks)

Q5. Influenza is a disease caused by a virus.

(a) Explain why it is difficult to treat diseases caused by viruses.

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(b) In some years there are influenza epidemics.

The graph shows the death rate in Liverpool during three influenza epidemics.

(i) The population of Liverpool in 1951 was approximately 700 000.

Calculate the approximate number of deaths from influenza in week 4 of the 1951 epidemic.

Show clearly how you work out your answer.

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(ii) In most years, the number of deaths from influenza in Liverpool is very low.

Explain, in terms of the influenza virus and the body’s immune system, why there were large numbers of deaths in years such as 1918 and 1951.

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(Total 7 marks)

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Read the following passage.

One of the deadliest diseases in history to be making a comeback in Britain. Doctors are alarmed at the rising number of cases of tuberculosis (TB) over the past three years, after decades in which it had declined. In the middle of the last century TB accounted for 16% of all deaths in Britain. The turning point in the fight against TB came in 1882 when Robert Koch identified the bacterium that causes the disease. In 1906 two French scientists began developing the vaccine to provide immunity against TB. The vaccine, BCG, (so-called from the initials of the two scientists) has routinely been injected into children aged 12 or 13 who are not already infected with the TB bacterium. BCG does not protect people who are already infected with TB. Recently, however, some Health Authorities have dropped their school vaccination programme.

(a) People infected with a small number of TB bacteria often do not develop the disease.

Explain, as fully as you can, how the body defends itself against the TB bacteria.

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(b) The BCG vaccine contains a mild form of the TB bacterium. A person injected with it does not develop the disease.

Explain, as fully as you can, how the vaccine makes the person immune to tuberculosis.

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(c) Explain why the BCG vaccine is not effective as a cure for people who already have tuberculosis.

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(Total 8 marks)

Q7. Many people who are overweight try slimming programmes.

A research study evaluated four different slimming programmes over 6 months.

Scientists selected a group of 40 people for each slimming programme and a control group.

Each of the five groups was matched for age, gender and mass.

The graph shows the results of the study.

Adapted from British Medical Journal, 2006, volume 332, pages 1309 –1314.

(a) Give two control variables that were used in this study.

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(b) Give two conclusions that can be drawn from the results of this study.

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(c) The costs of the four programmes were:

• Atkins book cost £3 • Rosemary Conley classes cost £140 for 6 months • Weight Watchers classes cost £170 for 6 months • Twice-daily Slim-Fast meal replacements cost £240 for 6 months.

Use this information and the graph to answer this question.

Which is the most cost effective of the four programmes?

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Explain the reason for your answer.

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(d) Some slimming programmes include daily exercise.

Explain how daily exercise helps a person to lose mass.

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(Total 8 marks)

Q8. Reflex actions are rapid and automatic.

(a) Name the following structures in a reflex action.

(i) The structure that detects the stimulus.

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(ii) The neurone that carries impulses to the central nervous system.

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(iii) The neurone that carries impulses away from the central nervous system.

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(iv) The structure that brings about the response.

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(b) Describe what happens at a synapse when an impulse arrives.

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(c) Some people have a condition in which information from the skin does not reach the brain.

Explain why this is dangerous for the person.

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(Total 8 marks)

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(a) Fill in the table about receptors. The first answer has been done for you.

(3)

RECEPTORS IN THE SENSITIVE TO

Eyes Light

Skin

Sound

Tongue

(b) Describe, in as much detail as you can, how information is transmitted from light receptors in the retina to the brain.

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(Total 6 marks)

Q10. Hormones are sometimes used to regulate human reproduction.

(a) (i) What is a hormone?

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(ii) How are hormones transported around the body?

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(b) Describe the benefits and possible problems that may result from the use of hormones to regulate human reproduction. You should refer to fertility drugs and contraceptives in your answer.

To gain full marks in this question you should write your ideas in good English. Put them into a sensible order and use the correct scientific words.

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(Total 6 marks)

Q11. Hormones are used in contraceptive pills.

(a) Explain how a contraceptive pill works.

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(b) Read the information about the trialling of the first contraceptive pill.

Evaluate the methods used by Pincus in trialling the contraceptive pill.

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(Total 7 marks)

The Pill was developed by a team of scientists led by Gregory Pincus. The team needed to carry out large scale trials on humans.

In the summer of 1955, Pincus visited the island of Puerto Rico. Puerto Rico is one of the most densely populated areas in the world. Officials supported birth control as a form of population control. Pincus knew that if he could demonstrate that the poor, uneducated women of Puerto Rico could use the pill correctly then so could women anywhere in the world.

The scientists selected a pill with a high dose of hormones to ensure that no pregnancies would occur while test subjects were taking the drug. The Pill was found to be 100% effective when taken properly. But 17% of the women in the study complained of side effects. Pincus ignored these side effects.

The women in the trial had been told only that they were taking a drug that prevented pregnancy. They had not been told that the Pill was experimental or that there was a chance of dangerous side effects.

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Q12. A person accidentally touches a hot pan.

Her hand automatically moves away from the pan.

The diagram shows the structures involved in this action.

(a) Describe fully how the structures shown in the diagram bring about this reflex action.

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(b) (i) The nerve pathway in this reflex action is about 1.5 metres in length. A nerve impulse travels at 75 m s–1.

Use this information to calculate the time taken for this reflex action to occur.


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Time intervals ....................................... s (2)

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(ii) The actual time interval is longer than the interval you have calculated in part (i).

Suggest an explanation for the difference.

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(Total 9 marks)

Q13. Atoms are made up of three main particles called protons, neutrons and electrons.

Use the periodic table on the data sheet to help you to answer these questions.

(a) Sodium is in Group 1 of the periodic table.

(i) Why are potassium and sodium in the same Group of the periodic table?

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(ii) How many protons are in an atom of sodium? ..................................... (1)

(iii) The atomic number of sodium is 11.

How many neutrons are in an atom of sodium with mass number 23?

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(iv) Each sodium atom has 11 electrons. Complete the electronic structure of sodium.

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(b) The chemical equation for a reaction of sodium is shown below.

2Na + Cl2 → 2NaCl

Describe this reaction of sodium in terms of the names of the substances and the numbers of the atoms involved.

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(Total 8 marks)

Q14. We can get many important substances from the Earth’s crust. Sometimes we can use these substances straight from the ground.

(a) Which one substance in the list can be used straight from the ground?

Draw a ring around the correct answer.

gold iron lead calcium aluminium (1)

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(b) In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate.

Rock salt is a mixture containing salt (sodium chloride) that we get from the Earth’s crust.

To get pure salt from rock salt we need to separate the pure salt from the other substances in the mixture.

Describe how you would obtain pure salt from rock salt in the laboratory. You should include in your answer the apparatus that you would use.

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(c) (i) Name the elements in pure salt.

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(ii) What is the chemical formula for pure salt?

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(Total 9 marks)

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Q15. A limestone quarry is in an area of natural beauty and near several villages. The company operating the quarry wants planning permission to build a new cement works in the quarry.

The diagram shows some of the substances used and produced at a cement works.

(a) Limestone is mainly calcium carbonate, CaCO3.

Write the correct number in the box to complete each sentence.

(i) The formula shows that calcium carbonate, CaCO3,

contains different elements. (1)

(ii) Calcium carbonate, CaCO3, contains a total number of atoms.

(1)

(b) The company wants the new cement works because the nearest cement works is 100 km from the quarry. The company argues that a new cement works sited inside the quarry would reduce carbon dioxide emissions.

Suggest why the new cement works might reduce carbon dioxide emissions.

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(c) Residents from the villages near the quarry are concerned that there will be atmospheric pollution from the new cement works.

(i) Name and explain how one of the emissions from the chimney causes atmospheric pollution.

Name of emission: ...........................................................................................

Explanation: .....................................................................................................

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(ii) Suggest what the company could do to reduce this atmospheric pollution.

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(Total 6 marks)

Q16. Limestone contains calcium carbonate, CaCO3

(a) The flow chart shows the stages in the limestone cycle.

Write the name of the correct calcium compound in each empty box to complete the flow chart.

(3)

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(b) Limestone is heated with clay to make cement. Cement is mixed with sand to make mortar.

A student investigated the strength of six mortar mixtures. Each mortar mixture contained 100cm3 cement but each contained a different volume of sand.

To do the investigation the student:

• added and stirred water into each mortar mixture

• put each mixture into the same sized moulds

• left each mixture to set hard

• dropped a metal ball from increasing heights until the mortar cracked

• recorded the results in a table.

Volume of sand in cm3

Volume of cement in cm3 Height the metal ball was

dropped from to crack the mortar in cm

700 100 24

600 100 30

500 100 36

400 100 37

300 100 48

200 100 54

(i) What happens to the strength of the mortar as the volume of sand increases?

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(ii) The student was worried about an anomalous result.

Which result was anomalous?

Volume of sand = ................. cm3

Explain why you have chosen this result.

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(c) The student repeated the investigation but used six concrete mixtures.

From the results the student concluded correctly that concrete was stronger than mortar.

Suggest one reason why concrete is stronger than mortar.

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(Total 7 marks)

Q17. Sea water contains magnesium ions. Magnesium oxide can be obtained from sea water using the following process.

(a) State the chemical name for limestone.

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(b) Write a word equation for the action of heat on limestone.

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(c) State the chemical name for slaked lime.

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(d) Write a balanced chemical equation for the addition of water to quicklime.

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(e) How can magnesium hydroxide be separated from sea water?

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(f) Suggest and explain how magnesium could be obtained from magnesium oxide.

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(Total 9 marks)

Q18. Limestone contains calcium carbonate, CaCO3.

At a cement works, limestone is mixed with clay and heated in a kiln.

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(a) (i) When methane is burned in this process the waste gases contain carbon dioxide and nitrogen.

Explain why.

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(ii) Complete the symbol equation for the thermal decomposition of calcium carbonate.

CaCO3 → ......................... + .........................

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(b) A different fuel is burnt at the cement works.

Suggest one reason the company may give for using this different fuel at the cement works.

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(c) The cement works continue to burn the different fuel.

Local residents are concerned because more children are suffering asthma attacks. Residents have also noticed that parked cars are becoming dirty because of smoke particles from the chimney.

The table shows the possible medical risk from smoke particles.

It is also recommended that to avoid damage to health, the concentration of any particles should be no higher than 2 parts per million (ppm).

Scientists were brought in to monitor the emissions from the cement work’s chimney. They positioned four sensors around the cement works to monitor airborne smoke particles.

Particle size in mm Medical effect

Larger than 0.4 No medical risks known

0.3 and smaller Causes asthma attacks

0.2 and smaller May cause cancer

These four sensors only detect particle sizes larger than 0.5 mm and measure the concentration of particles in ppm. The scientists reported that the particle sensors showed that the average concentration of particles was 1.8 ppm. The scientists concluded that there was no risk to health.

(i) Explain why the local residents objected to the positions of the four sensors.

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(ii) What evidence did the scientists use to conclude that there was no risk to health?

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(iii) The local residents were still concerned that there was a risk to health, even though the average concentration of particles was 1.8 ppm.

Explain why.

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(Total 11 marks)

Q19. (a) Balance these chemical equations.

(i) H2 + O

2 → H

2O

(1)

(ii) Al + O2 → Al

2O

3

(1)

(b) Briefly explain why an unbalanced chemical equation cannot fully describe a reaction.

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(Total 4 marks)

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Q20. The vacuum flask shown has five features labelled, each one designed to reduce heat transfer.

(a) (i) Which labelled feature of the vacuum flask reduces heat transfer by both conduction and convection?

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(ii) Explain how this feature reduces heat transfer by both conduction and convection.

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(b) (i) Which labelled feature of the vacuum flask reduces beat transfer by radiation?

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(ii) Explain how this feature reduces heat transfer by radiation.

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(Total 6 marks)

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Q21. A student was asked to investigate the heat loss from two metal cans, L and M. The cans were identical except for the outside colour.

The student filled the two cans with equal volumes of hot water. He then placed the temperature sensors in the water and started the data logger. The computer used the data to draw the graph below.

(a) Which one of the following is a categoric variable?

Put a tick ( ) in the box next to your answer.

the outside colour of the cans

the starting temperature of the hot water

the time

the volume of hot water (1)

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(b) For can L, state the temperature drop of the water:

(i) in the first two-minute interval

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(ii) in the second two-minute interval.

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(c) In both cans the water cooled faster at the start of the investigation than at the end of the investigation. Why?

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(d) One can was black on the outside and the other can was white on the outside.

What colour was can L? ..............................................

Explain the reason for your answer.

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(Total 7 marks)

Q22. The picture shows one type of solar water heater. Water from the tank is slowly pumped through copper pipes inside the solar panel where the water is heated by energy from the Sun.

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(a) Explain why the copper pipes inside the solar panel are painted black.

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(b) Each day the average European family uses 100 kg of hot water. To kill bacteria, the water going into the tank at 20 °C must be heated to 60 °C.

Calculate the energy needed to increase the temperature of 100 kg of water by 40 °C.

Specific heat capacity of water = 4200 J/kg °C.

Write down the equation you use, and then show clearly how you work out your answer.

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Energy transferred = .................................... J (2)

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(c) The bar chart shows how the amount of solar energy transferred to the water heater varies throughout the year.

How many months each year will there not be enough solar energy to provide the hot water used by an average European family?

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(d) In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate.

The water in the tank could be heated by using an electric immersion heater.

Outline the advantages and disadvantages of using solar energy to heat the water rather than using an electric immersion heater.

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(Total 11 marks)

Q23. A student had read about a glacier that had been covered in insulating material. The idea was to slow down the rate at which the glacier melts in the summer.

She investigated this idea using the apparatus shown in the diagram.

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(a) These are the steps taken by the student.

• Measure 30 cm3 of cold water into a boiling tube.

• Place the boiling tube 25 cm from an infra red lamp.

• Record the temperature of the water.

• Switch on the infra red lamp.

• Record the temperature of the water every minute for 5 minutes.

• Repeat with boiling tubes covered in different insulating materials.

(i) Why did she use an infra red lamp?

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(ii) Name one control variable in this investigation.

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(iii) Give one advantage of using a temperature sensor and data logger instead of a glass thermometer to measure temperature.

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(b) The results of the investigation are shown in the graph.

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(i) Why did the student use a boiling tube with no insulation?

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(ii) From her results, what should she recommend is used to insulate the glacier?

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(iii) Explain why the insulation recommended by the student will reduce the heat transfer from the Sun to the glacier.

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(c) Explain, in terms of particles, how heat is transferred through the glass wall of a boiling tube.

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(Total 9 marks)

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Q24. The drawing shows parts of a house where it is possible to reduce the amount of energy lost.

(a) Give one way in which the amount of energy lost can be reduced from each of the following parts of the house.

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(b) Energy consumption can be reduced by using a more efficient boiler or more efficient light bulbs.

What is meant by a more efficient light bulb?

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(Total 4 marks)

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Q25. The drawing shows water being heated in a metal saucepan.

(a) Explain, in terms of the particles in the metal, how heat energy is transferred through the base of the saucepan.

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(b) Energy is transferred through the water by convection currents. Explain what happens to cause a convection current in the water. The answer has been started for you.

As heat energy is transferred through the saucepan, the water particles at the bottom

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(c) Some energy is transferred from the hotplate to the air by thermal radiation. What is meant by thermal radiation?

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(Total 6 marks)

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Q26. The diagram below shows a house which has not been insulated. The cost of the energy lost from different parts of the house during one year is shown on the diagram.

(a) The total cost of the energy lost during one year is £1000.

(i) What is the cost of the energy lost through the floor?

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(ii) Suggest one way of reducing this loss.

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(b) The table below shows how some parts of the house may be insulated to reduce energy losses. The cost of each method of insulation is also given.

WHERE LOST COST OF ENERGY LOST PER YEAR (£)

METOD OF INSULATION

COST OF INSULATION (£)

roof 250 fibre-glass in loft 300

walls 350 foam filled cavity 800

windows 100 double glazing 4500

doors 150 draught proofing 5

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(i) Which method of insulation would you install first? Explain why.

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(ii) Which method of insulation would you install last? Explain why.

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...........................................................................................................................

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........................................................................................................................... (3)

(Total 9 marks)

Q27. (a) The diagram shows how much heat is lost each second from different parts of an uninsulated house.

(i) Each year, the house costs £760 to heat.

How much money is being wasted because of heat lost through the roof?


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(ii) Insulating the loft would cut the heat lost through the roof by 50 %.

The loft insulation has a payback time of years.

How much did the loft insulation cost to buy?

..........................................................................................................................

Cost of loft insulation = £ ................................................. (1)

(b) What happens to the wasted energy?

....................................................................................................................................

.................................................................................................................................... (1)

(Total 4 marks)

Q28. The table gives information about some methods of conserving energy in a house.

Conservation method Installation cost in £

Annual saving on energy bills in £

Cavity wall insulation 500 60

Hot water tank jacket 10 15

Loft insulation 110 60

Thermostatic radiator valves 75 20

(a) Explain which of the methods in the table is the most cost effective way of saving energy over a 10 year period. To obtain full marks you must support your answer with calculations.

.....................................................................................................................................

.....................................................................................................................................

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(b) Describe what happens to the energy which is 'wasted' in a house.

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..................................................................................................................................... (2)

(Total 5 marks)

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M1. (a)

All four for 3 marks two or three for 2 marks one for 1 mark

3

Disease Caused by bacteria

Caused by viruses

Influenza

Mumps

Cholera

Tuberculosis

(b) Marks awarded for this answer will be determined by the Quality of Written Communication (QWC) as well as the standard of the scientific response.

No relevant content. 0 marks

There is a brief description of the process by which the human body develops immunity after vaccination.

Level 1 (1–2 marks)

There is a description of the process by which the human body develops immunity after vaccination.


There is a clear and detailed description of the process by which the human body develops immunity after vaccination.


examples of the points made in the response

• when a vaccination is given, dead or weakened pathogens are injected into the body

• the white blood cells respond by producing antibodies

• some of these white blood cells survive in the body

• and act as ‘memory cells’

• when the same pathogens enter the body again the white blood cells rapidly produce antibodies

• which destroy the pathogen

• this prevents illness developing. [9]

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M2. (a) (i) viruses live inside cells 1

viruses inaccessible to antibiotic allow drug / antibiotic (if used) would (have to) kill cell

1

(ii) mutation ignore mutation caused by antibiotic

1

natural selection or no longer recognised by antibiotics

accept description of natural selection 1

(b) (stimulate) antibody production ignore antitoxin

1

(by) white cells 1

rapidly produce antibody on re-infection ignore antibodies remain in blood

1 [7]

M3. (a) antibiotics diffuse / pass (into agar)

do not allow into dish 1

kill / prevent growth of bacteria or destroy cell wall / bacteria accept bacteria are dead

1

(b) it / higher concentration kills more bacteria or causes less growth

do not accept anything referring to size of circle 1

levels off (at 6 units) accept above 4 units

1

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(c) Quality of written communication: for correct sequencing or linking of ideas or points

this mark can only be awarded for a plausible attempt (not necessarily biologically correct) to link a precaution to a purpose Q or Q

1

Loop flamed

to sterilise it / kill unwanted microorganisms accept so no bacteria present do not accept to clean it

1

Lid taped

prevent bacteria getting in / out or prevent someone touching bacteria

accept microorganisms/fungi for bacteria do not accept viruses or germs

1

25°C

prevents / reduces growth of / reproduction 1

harmful bacteria / microorganisms or pathogens 1

(d) any two from:

• to avoid over-use of antibiotics or use no / less / low concentration antibiotics

• select antibiotic that is most effective

• finish the course

• don’t give or use for animals

• develop new antibiotics or alternatives 2

[11]

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M4. (a) Quality of written communication The answer to this question requires ideas in good English in a sensible order with correct use of scientific terms. Quality of written communication should be considered in crediting points in the mark scheme

idea of mutation or variation

do not allow ‘bacteria get used to antibiotics’ or idea that antibiotics change the bacteria or ‘bacteria become immune’ or references to adaptation or evolution

1

(resistant cells) survive antibiotic 1

(resistant cells) breed 1

(b) EITHER (yes)

keep animals disease free (1) so grow faster (1 mark) or live longer

OR (no)

resistant bacteria may develop (1) risk to human or animal health (1)

allow bacteria become resistant / immune 2

[5]

M5. (a) any two from

• live inside / infect body cells

• difficult for drugs to enter (body) cells / drug would kill (body) cell

• antibiotics ineffective against viruses

• viruses mutate frequently 2

(b) (i) 420 correct answer with or without working if answer incorrect evidence of ‘number of deaths’ × 7 or 60 seen gains 1 mark ignore 6 000 000

2

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(ii) any three from:

• virus / flu mutates

• people no longer / not immune ignore resistance

• white blood cells / memory cells / immune system do not recognise virus

• relevant reference to antibodies / antigens

• current vaccine ineffective or no vaccine available then or takes time to develop new vaccine

allow no tamiflu / anti-viral drugs

• conditions less hygienic / lack of hygiene

• people in poor health (following world wars) allow people had ‘weak’ immune system

3 [7]

M6. (a) white cells ingest bacteria produce antibodies which destroy bacteria produce antitoxins which counteract poisons produced by bacteria

for 1 mark each 3

(b) dead/mild microbes stimulate antibody production white cells can quickly produce these again

for 1 mark each 3

(c) adds more bacteria (mild) does not affect TB bacteria

for 1 mark each 2

[8]

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M7. (a) any two from:

• age

• gender

• mass

• number in group

• time 2

(b) any two from:

• highest (mean) mass loss on Rosemary Conley or Rosemary Conley most effective

• least (mean) mass loss in control group or mean 2

(c) (Atkins)

costs least 1

mass loss very similar to other diets or second highest mass loss or as effective as other diets

1

(d) any two from:

• (exercise) increases metabolic rate / respiration ignore sweating

• (exercise) needs / uses energy / calories allow burns fat / calories do not accept energy for respiration

• (this) energy comes from food / fat

• less food / energy/ calories converted to fat 2

[8]

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M8. (a) (i) receptor

allow named receptor eg light receptor ignore sensory neurone allow sense organ / named sensory organ eg skin / eye

1

(ii) sensory (neurone) allow afferent

1

(iii) motor (neurone) allow efferent

1

(iv) effector / muscle / gland / named 1

(b) any two from:

• impulse / information passes from one neurone to another or impulse / information passes across gap

• chemical / transmitter involved

• diffusion (across gap) 2

(c) brain / person not aware of pain / stimulus / can’t feel allow brain/ person doesn’t know / realise / unable to coordinate ignore reflex ignore information

1

possibility of (permanent / serious) damage / eg burning ignore danger

1 [8]

M9. (a) pressure / temperature / hot / cold / touch / pain ear / cochlea chemicals / taste / named taste e.g. salt (reject skin receptors e.g. hot, cold)

for 1 mark each 3

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(b) impulses / electrical pulse / electrical signal (reject information, message, pulse, signal) via sensory neurones (ignore relay neurone, synapse) (in) optic nerve (allow 1 mark for via nerves or neurone if neither second nor third mark scored, reference to spinal cord disqualified route mark)

for 1 mark each 3

[6]

M10. (a) (i) any one from:

• chemical messenger

• chemical / substance released in one part to have effect elsewhere in body

• chemical / substance which affects another / target organ / tissues / cells allow chemical from endocrine gland

1

(ii) in blood / circulatory system / any named part including plasma extra wrong answer would cancel example not red blood cells

1

(b) Quality of written communication: correct use of at least two relevant scientific terms spelt phonetically

e.g. pregnancy, ovulation, FSH, oestrogen, progesterone, ovary, follicle, circulation, thrombosis, feminisation, sperm count, STD Q or Q

1

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any three from:

Oral contraceptives:

(benefit)

• prevent (unwanted) pregnancy or prevent egg release

• regulate menstrual cycle / periods

(problems)

• prolonged use may prevent later ovulation / cause infertility

• named side-effect on female body e.g. circulatory problems / weight gain / nausea / headache / breast cancer / mood swings

• increased promiscuity / increase in STD’s / STI’s

• named side-effect on environment e.g. feminisation of fish or lowered sperm count in human males

Fertility drugs:

(benefit)

• can enable woman to have children or to become pregnant or stimulates egg release

(problem)

• multiple births for full marks must score at least one re contraceptives and at least one re fertility drugs if unclear which type of hormone maximum 2 marks from 3

3 [6]

M11. (a) inhibits FSH (production / secretion) 1

(therefore) no eggs mature / released if no other marks gained allow 1 mark for no eggs produced

1

or

effect of FSH on ovary described references to LH are neutral

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(b) maximum 4 marks if no conclusion

Pros max 2marks from 4 marks e.g.

• large scale trial gave better results

• chose uneducated women so that if these women could use it correctly, women elsewhere would be able to cons max 3 marks from 4 marks e.g.

• used pill with high dose of hormone – either so results not valid for general use of hormone or dangerous

• side effects ignored

• women not told pill was experimental / pill might have side effects

• no placebo

• should have tried a range of doses

• should have done pre-trial to check for side effects 4

conclusion 1 mark e.g. trials flawed therefore cons outweigh pros

accept reverse e.g. trials flawed but pros outweigh cons 1

[7]

M12. (a) stimulus / heat detected by temperature receptors in skin 1

impulses travel along sensory neurone to spinal cord / CNS 1

chemical transmission across synapse 1

via relay neurone 1

impulses to muscle / effector via motor neurone 1

muscle / effector contracts, moving the hand away 1

(b) (i) 0.02 s correct answer gains 2 marks if answer incorrect, evidence of 1.5 / 75 gains 1 mark

2

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(ii) impulse slowed down because of time taken for diffusion of the chemical across the synapse

1 [9]

M13. (a) (i) both have one / 1 electron in the outer energy level / shell

allow both react in a similar way 1

(ii) eleven / 11 1

(iii) twelve / 12 1

(iv) (2x) max 1 if candidate changes the number of electrons in the first energy level / shell

8x (in second energy level / shell) 1

1x (in outer energy level / shell) 1

(b) two sodium atoms (react) 1

two (bonded) chlorine atoms (react) allow one chlorine molecule (reacts)

1

two sodium ions and two chloride ions (are produced) allow two molecules of sodium chloride (are produced) or two sodium chloride particles (are produced)

1 [8]

M14. (a) gold 1

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(b) Marks awarded for this answer will be determined by the Quality of Written Communication (QWC) as well as the standard of the scientific response.


There is a brief description of the laboratory procedure for obtaining a sample of pure salt from rock salt. The answer would not necessarily allow the procedure to be completed successfully by another person.


There is a description of the laboratory procedure for obtaining a sample of pure salt from rock salt that could be followed by another person. The answer must mention that the rock salt is mixed with water.


There is a clear, detailed description of the laboratory procedure for obtaining a sample of pure salt from rock salt that could easily be followed by another person. The answer must mention that the rock salt is mixed with water.



• crush the rock salt

• with a mortar and pestle

• mix the crushed rock with water

• in a beaker

• stir and warm to dissolve the salt

• filter the mixture to remove the undissolved solids

• using filter paper and funnel

• put the filtrate into an evaporating dish

• warm using Bunsen burner, tripod and gauze

• to evaporate to dryness

(c) (i) sodium and chlorine must have both for the mark do not accept chloride

1

(ii) NaCl 1

[9]

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M15. (a) (i) 3 / three 1

(ii) 5 / five 1

(b) any one from:

• less / no transport accept less / no distance

• less / no (fossil) fuel used ignore references to carbon dioxide / carbon emissions

1

(c) (i) carbon dioxide / CO2

for a correct emission 1

(causes) global warming / climate change / greenhouse gas explanation must be correct for named emission ignore ozone layer

or

(cement) particles / smoke (1)

(causes) asthma / dust / (global) dimming (1) accept breathing problems

or

sulfur dioxide / SO2 / nitrogen oxides / NO

x (1)

(causes) acid rain (1) do not accept nitrogen or water vapour for emissions do not accept no named emission

1

(ii) absorb / trap / capture / filter / pass through water / scrub / electrostatic attraction ignore condense / off setting / different fuel

1 [6]

M16. (a) calcium oxide 1

calcium hydroxide 1

calcium carbonate 1

substances must be in the order shown

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(b) (i) strength of mortar decreases (as volume of sand increases) 1

(ii) 400 (cm3)

1

because the height the metal ball dropped from should be 42 cm and not 37 cm

accept because the other results show that the height the metal ball dropped from should have an interval of 6cm

1

(c) contains aggregate allow bonding is stronger

1 [7]

M17. (a) calcium carbonate

not formula 1

(b) calcium carbonate → calcium oxide not common names allow correct formulae

1

+ carbon dioxide 1

(c) calcium hydroxide not formula

1

(d) CaO + H2O → Ca(OH)

2

allow if doubled

all formulae correct, no extra ones 1

balanced 1

(e) filtration allow centrifugation

not decanting not evaporation, crystallisation

1

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(f) electrolysis stated or implied

molten MgO / magnesium oxide is ionic / Mg2+ goes to cathode

not just heated 1

or add sodium / K / Ca / Li / a more reactive metal 1

displaces Mg / reduces Mg give no marks if reference made to reduction by C or H

1 [9]

M18. (a) (i) oxygen / air reacts with carbon / methane (to form carbon dioxide)

accept from the decomposition / reaction of calcium carbonate ignore CO

2 from the air

1

nitrogen is (unreacted) from the air 1

(ii) CaO 1

CO2

any order ignore words any incorrect balancing max 1 mark

1

(b) any one from:

• more energy / efficient allow converse for present fuel

• from a sustainable / renewable resource

• produces less / no carbon dioxide / greenhouse gases / global warming ignore no pollution / environmental damage

• more profit or money for local economy

accept fuel is cheap(er)

• more readily available it = different fuel

1

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(c) (i) any two from:

• not near where people / residents live accept not between cement works and where people live ignore sensors are unsightly

• not positioned where concentration of particles was likely to be highest

• not positioned downwind 2

(ii) the average / concentration was 1.8(ppm) or the average / concentration was below 2(ppm)

accept 1.8(ppm) is less than 2.0 (ppm) 1

(iii) any three from:

• children / people suffering asthma attacks

• result was an average

• readings (at some (2/3) sensors) could have been higher than 2ppm

• sensors did not detect particles below 0.5mm

• small particles / particles below 0.5mm / 0.4mm / 0.3mm / 0.2mm could (still) cause cancer / asthma ignore global dimming or cars becoming dirty or position of sensors

3 [11]

M19. (a) (i) H2 + O

2 → H

2O *both circled correct

for 1 mark 1

(ii) A1 + O2 → A1

2O

3 all circled correct

for 1 mark 1

(b) idea that: must end up with the same number of atoms as at the start

any 2 each

otherwise matter is shown to be lost/gained for 1 mark

won’t show correct amount of each element/compound 2

[4]

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M20. (a) (i) vacuum

do not allow stopper 1

(ii) (absence of particles) means no (transfer of energy between) particles for conduction

accept particles or atoms or molecules or electrons 1

no movement of molecules for (transfer of energy by) convection accept particles/atoms/electrons if answer to (a)(i) is correct: then in (a)(ii) have stated ‘conduction and convection both need a medium/particles/materials’ = 2 marks (If medium is specified, it must be correct, conduction can be solid, liquid or gas, convection must be liquid or gas) if answer to (a)(i) is incorrect then in (a)(ii) have stated ‘conduction and convection both need a medium...’= 1 mark, unless further qualified by stating about absence of particles, in which case get a second mark.

1

(b) (i) silvered surface accept silver surface

1

(ii) silvered is a bad emitter/radiator 1

surface reflects heat/energy/radiation (at inner and outer surface) or is a bad absorber (of energy)

accept bounces off 1

[6]

M21. (a) the outside colour of the cans 1

(b) (i) 18 (°C) or 88 to 70

ignore negative sign 1

(ii) 8 (°C) or 70 to 62

ignore negative sign 1

(c) greater temperature difference between water and surroundings (at start) must mention temperature difference ignore just water hotter accept energy used to heat cans initially

1

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(d) black 1

temperature falls the fastest (in L) accept (can L) loses more heat / cools quicker accept heat for temperature

1

black is a good / the best / better emitter (of heat / radiation) accept converse ignore black is best absorber

1 [7]

M22. (a) because black is a good absorber of radiation 1

there will be a faster transfer of energy allow the temperature of the water rises faster

1

(b) 16 800 000 allow 1 mark for substitution into correct equation ie 100 × 4200 × 40

2

(c) 7 allow ecf from part (b)

1

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(d) Marks awarded for this answer will be determined by the Quality of Written Communication (QWC) as well as the standard of the scientific response.


There is a brief description of the advantages and disadvantages of using solar energy to heat the water rather than using an electric immersion heater, including either advantages or disadvantages from the examples below.

Level 1 (1-2 marks)

There is a description of some of the advantages and disadvantages of using solar energy to heat the water rather than using an electric immersion heater, with at least one advantage and one disadvantage from the examples below.

Level 2 (3-4 marks)

There is a clear, balanced and detailed description of the advantages and disadvantages of using solar energy to heat the water rather than using an electric immersion heater, with a minimum of two advantages and two disadvantages from the examples below.

Level 3 (5-6 marks)


advantages

accept specific examples of polluting gases

• a renewable energy source

• energy is free

• does not pollute the atmosphere

• no fuel is burnt

• energy can be stored (in the water)

disadvantages

accept unreliable energy source

• only available in daylight hours

• availability fluctuates

• insufficient hours of sunlight in some countries

• average low intensity in some countries [11]

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M23. (a) (i) as a source of thermal radiation

accept heat for thermal radiation accept to act as the Sun do not accept sunlight alone

1

(ii) any one from:

• volume of water accept amount for volume

• distance between lamp and boiling tube

• initial / starting temperature of water

• same room temperature do not accept time or same insulation material

1

(iii) any one from:

• greater sensitivity / precision do not accept more reliable (negates mark)

• could link to a computer for (automatic) data analysis

• could take more frequent readings

• reduces instrument reading error accept more accurate do not accept easier to use on its own

1

(b) (i) acts as a control accept to be able to make a comparison accept to see the difference do not accept ‘to make it a fair test’ OWTTE on its own

1

(ii) (plastic) foam and aluminium foil 1

(iii) (aluminium) foil is a poor absorber of thermal radiation accept heat / infra red for thermal radiation

1

or (aluminium) foil is a (good) reflector of thermal radiation

do not accept ‘reflects sunlight’ on its own

(plastic) foam traps air which is a (good) insulator accept (plastic) foam is a poor conductor / (good) insulator do not accept ‘the material’ is a good insulator / poor conductor

1

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(c) particles vibrate with a bigger / stronger amplitude / faster / with more (kinetic) energy

accept particles vibrate more do not accept start to vibrate only

1

energy transferred by collisions with other particles do not accept answers in terms of free/mobile electrons

1 [9]

M24. (a) insulation

allow example e.g fibreglass 1

double glazing allow curtains

1

draught excluder allow double glazing / close fitting door allow turning down thermostat once only / turn down the heating

1

(b) transfers more useful energy allow converts more energy into light / less into heat / less energy wasted

1 [4]

M25. (a) ions / electrons gain (kinetic) energy

accept atom / particles / molecules for ion accept ions vibrate faster accept ions vibrate with a bigger amplitude accept ions vibrate more do not accept ions move faster

1

(free) electrons transfer energy by collision with ions or energy transferred by collisions between vibrating ions

1

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(b) move faster or take up more space do not accept start to move / vibrate

1

(warmer) water expands or becomes less dense (than cooler water)

do not accept answers in terms of particles expanding 1

warm water rises (through colder water) or colder water falls to take its place 1

(c) transfer of energy by waves / infrared (radiation) accept rays for waves do not accept transfer of energy by electromagnetic waves ignore reference to heat

1 [6]

M26. (a) (i) £150

gets 2

Else 1000 – (250 + 350 + 100 + 150) or 1000 – 850 gets 1

2

(ii) (Named) floor covering OR Insulation under floor

for 1 mark 1

(b) (i) Draught proof doors or fibre glass in loft or in cavity For draught proofing

gains 1 mark

Very low cost/easy to install Repays for itself quickly/cost recuperated quickly Reasonable energy saving

any 2 for 1 mark each

For loft insulation

Second lowest installation cost/easy to install Reasonable large energy savings for this cost Reasonable payback time

gains 1 mark

For foam filled cavity Biggest energy/cash saving Cost effective

any 2 for 1 mark each 3

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(ii) Double glazing

gains 1 mark

Costs most Saves least energy Least cost effective

any 2 for 1 mark each 3

[9]

M27. (a) (i) £190

nb mention idea of cost per J in £ will come to an approx figure full credit given allow 1 mark for showing that the energy loss through the roof is ¼ of the total energy loss ie 150 / 600

2

(ii) £142.50 allow ecf 50 % of their (a)(i) × 1.5 ie their (a)(i) × 0.75

1

(b) transferred to surroundings / atmosphere

or becomes spread out 1

[4]

M28. (a) loft insulation 1

energy saved in 10 years £600 1

net saving (600 – 110) £490 1

OR

hot water jacket 1

energy saved in 10 years £140 1

This is the highest percentage saving on cost 1

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(b) transferred to environment / surroundings 1

as heat / thermal energy 1

[5]

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(6) (total 9 marks) - wikispacestavistockcollegescience.wikispaces.com/file/view/core+science... ·...

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