Q1.
Antibiotics are drugs used to treat bacterial infections.
Mutations in bacteria produce new strains.
Some strains of bacteria are resistant to antibiotics.
(a)  Where do mutations happen in a bacterial cell?
___________________________________________________________________
(1)
A scientist investigated which antibiotics (A, B, C, D and E) killed Staphylococcus aureus (S. aureus) bacteria.
This is the method used.
1. Grow S. aureus bacteria in a Petri dish.
2. Cut five small discs of paper.
3. Soak each paper disc in a different antibiotic solution.
4. Put the five paper discs into the Petri dish.
5. Keep the Petri dish at 37 °C for 24 hours.
Figure 1 shows the results.
A clear area around a disc shows where the bacteria have been killed.
Figure 1

(b)  The scientist concluded:
‘S. aureus is resistant to antibiotics C and E’.
Explain the evidence for this conclusion.
Use Figure 1.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(2)
(c)  The scientist later discovered that S. aureus is not resistant to antibiotic E.
Suggest how the method was developed and showed that S. aureus is not resistant to antibiotic E.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(2)
Broken bones are sometimes repaired using a metal implant.
The area around an implant can become infected with S. aureus bacteria. The infection is usually treated with a long-term course of antibiotics.
Long-term use of antibiotics has led to the development of antibiotic resistant bacteria. Research is being carried out into alternative treatments.
Stem cells from bone marrow and from fat tissue have antimicrobial properties.
A scientist investigated the effect of four treatments on the area of infection around metal implants. Each treatment was injected into the area around the implant.
The four treatments were:
•   unreactive solution
•   antibiotic solution
•   stem cells from fat tissue
•   stem cells from fat tissue containing antibiotic.
Each treatment was tested on 5 patients where an infection had developed around their metal implant.
After 7 days of treatment, the scientist calculated the ratio:
area of infection : total tissue area
(d)  What was the independent variable in this investigation?
Tick (✓) one box.
 
The ratio of area of infection : total tissue area		
The treatment injected around the implant		
The type of antibiotic used		
The type of bacterial infection		
(1)
(e)  Suggest one advantage of using stem cells from fat tissue, rather than using stem cells from bone marrow.
___________________________________________________________________
___________________________________________________________________
(1)
(f)   Stem cells containing antibiotic were produced by growing the cells for 24 hours in a solution containing the antibiotic.
How did the antibiotic enter the stem cells from the solution?
Give a reason for your answer.
Tick (✓) one box.
 
By active transport		
By diffusion		
By osmosis		
By translocation		
Reason  ____________________________________________________________
___________________________________________________________________
(2)
Figure 2 shows the results.
Figure 2

(g)  What is the range of results for the treatment with stem cells only?
From  ____________________ to ____________________
(1)
(h)  A student looked at the results and concluded:
‘Injections of stem cells containing antibiotic should be used 
to treat all implant-related infections’.
Evaluate the student’s conclusion.
Use Figure 2.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(4)
(Total 14 marks)
Q2.
Pathogens are microorganisms that cause diseases.
Gonorrhoea, malaria and measles are three diseases in humans.
(a)  Draw one line from each disease to the pathogen that causes the disease.
 
Disease	 	Pathogen	
 	
 	 	Bacterium	
Gonorrhoea	 	 	
 	 	Fungus	
Malaria	 	 	
 	 	Protist	
Measles	 	 	
 	 	Virus	
(3)
(b)  Malaria is transmitted by mosquitos.
Male mosquitos can be sterilised so they are infertile.
The spread of malaria is reduced by releasing sterile mosquitos into the environment.
Explain how releasing sterile mosquitos reduces the spread of malaria.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(2)
Pathogens also cause diseases in plants.
The figure below shows a rose black spot fungal spore and a tobacco mosaic virus.

(c)  Name the piece of equipment used to view the virus.
___________________________________________________________________
(1)
(d)  How many times longer is the fungal spore than the virus?
Use the figure above.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
Number of times longer = _______________
(3)
(e)  Explain why plants infected with tobacco mosaic virus grow slowly.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(3)
(Total 12 marks)
Q3.
Cells are the basic units of all forms of life.
(a)     Describe four differences between a bacterial cell and a plant cell.
1. _________________________________________________________________
___________________________________________________________________
2. _________________________________________________________________
___________________________________________________________________
3. _________________________________________________________________
___________________________________________________________________
4. _________________________________________________________________
___________________________________________________________________
(4)
(b)     Gonorrhoea is a bacterial disease.
A new vaccine is being developed against gonorrhoea.
Describe how a vaccine would work to prevent gonorrhoea.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(4)
Another disease caused by bacteria is salmonella food poisoning.
In the UK, chickens are vaccinated against Salmonella bacteria to reduce the number of cases of food poisoning in humans.
(c)     Explain how vaccinating chickens reduces the number of cases of salmonella food poisoning.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(2)
(d)     Give one way that the spread of salmonella food poisoning from one human to another is controlled.
Do not refer to vaccination in your answer.
___________________________________________________________________
___________________________________________________________________
(1)
(e)     The number of cases of salmonella food poisoning is usually higher in summer than in winter.
Suggest one reason why.
___________________________________________________________________
___________________________________________________________________
(1)
(Total 12 marks)
Q4.
New drugs are tested and trialled before they can be licensed to treat patients.
The graph below shows how much time the different stages of testing took for one new drug.

(a)     How much more time did the clinical trials take compared with the preclinical testing?
Tick (✓) one box.
 
3 years		
3.5 years		
5 years		
6.5 years		
(1)
During Phase 1 clinical trials low doses of the drug are tested on healthy volunteers.
(b)     Suggest one reason why low doses of the drug are used in Phase 1 clinical trials.
___________________________________________________________________
___________________________________________________________________
(1)
(c)     Suggest two reasons why healthy volunteers are used in Phase 1 clinical trials.
1. _________________________________________________________________
___________________________________________________________________
___________________________________________________________________
2. _________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(2)
(d)     The results of clinical trials can only be published after peer review by other scientists.
Suggest one reason why the results must be reviewed by other scientists.
___________________________________________________________________
___________________________________________________________________
(1)
(e)     A drug is only licensed for the medical conditions it was tested to treat in the clinical trials.
Drug regulations:
•        control what drugs a doctor can prescribe
•        ensure doctors can prescribe a drug with confidence
•        protect patients.
AMD is an eye condition that can result in very poor vision.
Doctors treat approximately 40 000 new cases of AMD each year.
Two drugs licensed to treat AMD in the UK are drug A and drug B.
In many other countries drug C is used to treat AMD. Drug C is only licensed in the UK to treat cancer.
The cost per injection for each drug is:
•        drug A £561
•        drug B £800
•        drug C £28
The number of injections required to treat AMD is the same for each drug.
In 2018 the High Court in the UK gave permission for drug C to be used to treat AMD.
Evaluate the decision to allow the use of drug C to treat AMD in the UK.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(6)
(Total 11 marks)
Q5.
Malaria is a disease caused by a microorganism carried by mosquitoes.
The microorganism is transferred to humans when adult female mosquitoes feed on human blood.
The figure below shows the life cycle of a mosquito.
 
© watcharapon/iStock
The World Health Organisation estimates that 3 × 108 people are infected with malaria every year.
Scientists estimate that malaria kills 2 × 106 people every year.
The people who are infected with malaria but do not die, may be seriously ill and need health care for the rest of their lives.
(a)     Based on the estimated figures, what percentage of people infected with malaria die from the disease?
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(2)
(b)     An internet article states:
1       Mosquito larvae are at the start of the food chain for some fish.
2       Adult mosquitoes provide food for bats and birds.
3       Mosquitoes are also important in plant reproduction because they feed from flowers of crop plants.
(i)      The first sentence in the article is not correct.
Explain why.
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
(2)
(ii)      A company plans to produce genetically modified (GM) adult male mosquitoes.
The GM mosquitoes will carry a gene from bacteria. The gene causes the death of offspring before they become adults.
Male mosquitoes do not feed on blood.
Scientists are considering releasing millions of adult male GM mosquitoes into the wild.
Do you think scientists should release millions of male GM mosquitoes into the wild?
In your answer you should give advantages and disadvantages of releasing GM mosquitoes into the wild.
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
(4)
(iii)     Describe the process for creating a GM mosquito.
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
(3)
(Total 11 marks)
Q6.
Pathogens are microorganisms that cause infectious diseases.
(a)  What type of pathogen causes malaria?
Tick (✓) one box.
 
Bacterium		
Fungus		
Protist		
Virus		
(1)
(b)  Give two methods used to prevent people catching malaria.
Give a reason why each method works.
Method 1 ___________________________________________________________
___________________________________________________________________
Reason  ____________________________________________________________
___________________________________________________________________
___________________________________________________________________
Method 2 ___________________________________________________________
___________________________________________________________________
Reason  ____________________________________________________________
___________________________________________________________________
___________________________________________________________________
(4)
(c)  Describe two differences between a bacterial cell and a eukaryotic cell.
1  _________________________________________________________________
___________________________________________________________________
___________________________________________________________________
2  _________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(2)
A scientist investigated the population growth of bacteria in a culture solution.
At the start of the investigation the culture solution contained all the nutrients the bacteria needed.
The scientist determined the number of living bacterial cells in the solution every hour over two days.
Figure 1 shows the apparatus used.
Figure 1
 
(d)  Describe why there are air holes in the cap of the culture bottle.
___________________________________________________________________
___________________________________________________________________
(1)
Figure 2 shows the scientist’s results.
Figure 2
 
(e)  Give one reason for what is happening to the number of bacteria at each of the stages.
Stage A ____________________________________________________________
___________________________________________________________________
___________________________________________________________________
Stage B ____________________________________________________________
___________________________________________________________________
___________________________________________________________________
Stage C ____________________________________________________________
___________________________________________________________________
___________________________________________________________________
Stage D ____________________________________________________________
___________________________________________________________________
___________________________________________________________________
(4)
(f)   Figure 3 shows two cubes.
Cube X represents a bacterial cell.
Cube Y represents a small multicellular organism.
Figure 3
 
A bacterial cell can absorb all the nutrients it needs by diffusion through its outer surface.
Explain why a multicellular organism cannot absorb all the nutrients it needs by diffusion through its outer surface.
You must include calculations in your answer.
Use Figure 3.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(5)
(Total 17 marks)
Q7.
In 2014 there was an outbreak of Ebola virus disease (EVD) in Africa.
At the time of the outbreak there were:
•        no drugs to treat the disease
•        no vaccines to prevent infection.
(a)     By March 2015 there were an estimated 9 850 deaths worldwide from EVD.
The number of deaths is an estimate.
Suggest why it is an estimate rather than an exact number.
___________________________________________________________________
___________________________________________________________________
(1)
(b)     Why were antibiotics not used to treat EVD?
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(1)
(c)     After the outbreak began, drug companies started to develop drugs and vaccines for EVD.
A drug has to be thoroughly tested and trialled before it is licensed for use.
Testing, trialling and licensing new drugs usually takes several years.
Draw one line from each word about drug testing to the definition of the word.
 
Word about drug testing	 	Definition	
 	 	 	 	 	
 	Dose	 	 	Side effects making the person ill	
 	 	 	 	 	
 	Efficacy	 	 	The concentration of the drug to be used and how often the drug should be given	
 	 	 	 	 	
 	Toxicity	 	 	Whether the drug works to treat the illness	
(2)
(d)     The results of drug testing and drug trials are studied in detail by other scientists.
Only then can the results be published by the drug company.
Suggest one reason why the results are studied by other scientists.
___________________________________________________________________
___________________________________________________________________
(1)
(e)     The number of deaths from EVD continued to increase.
The World Health Organization (WHO) decided it was ethical to use unlicensed drugs.
The WHO said unlicensed drugs could only be given to people who gave their permission.
Also, any results had to be shared with other researchers and drug companies.
Some vaccines had shown positive results in animal testing, but the vaccines had not been tested and trialled in humans.
The supplies of the vaccine were low.
At first the vaccines were only used for health workers.
How would the use of a vaccine reduce the spread of EVD?
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(2)
(f)     Evaluate the use of unlicensed drugs and vaccines during the EVD outbreak.
Give a conclusion.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(6)
(Total 13 marks)
Q8.
Measles is a serious disease. A person can die from measles.
The table below shows the number of medically confirmed cases of measles in England and Wales between 2012 and 2015
 
Year	Number of medically confirmed cases of measles	
2012	2030	
2013	1843	
2014	121	
2015	91	
(a)  Suggest one reason why the actual number of cases of measles in England and Wales might be higher than is shown in the table above
___________________________________________________________________
___________________________________________________________________
(1)
(b)  Calculate the percentage decrease in the number of medically confirmed cases of measles between 2012 and 2015
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
Percentage decrease = _______________________ %
(2)
(c)  One reason for the decrease in the number of cases of measles is that more children were vaccinated against the disease.
Vaccinating a large proportion of the population reduces the spread of the measles virus.
Explain why.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(2)
(d)  The graph below shows the concentration of measles antibodies in the blood of a boy.
 
Explain the differences between antibody production after the vaccine injection and after exposure to the measles virus.
You should include data from the graph above
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(6)
(Total 11 marks)
Q9.
This question is about sexually transmitted infections (STIs).
Figure 1 shows the number of STIs diagnosed in England in 2015.
Figure 1

(a)     The total population of females aged 15‒19 was 1 572 189
Calculate the number of females aged 15‒19 who were diagnosed with an STI.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
Number of females = ____________________ 
(3)
(b)     Suggest why the data is given per 100 000 of the population and not as the number of people.
___________________________________________________________________
___________________________________________________________________
(1)
(c)     Gonorrhoea is an STI.
Describe the symptoms of gonorrhoea.
___________________________________________________________________
and
___________________________________________________________________
(1)
Gonorrhoea was treated using penicillin until resistant strains of Gonorrhoea bacteria appeared.
A new antibiotic is tested to treat gonorrhoea.
Scientists need to know the concentration of antibiotic that will be most effective and safe.
This is the method used.
1.     Soak paper discs in different concentrations of antibiotic solution.
2.     Place one disc in the centre of an agar plate where Gonorrhoea bacteria are growing.
3.     Incubate the agar plate at 37 °C for 24 hours.
4.     Measure the diameter of the clear area where the bacteria are killed.
5.     Repeat steps 2‒4 for each concentration of the antibiotic solution.
Figure 2 shows the results for one concentration of the antibiotic solution.
Figure 2

The table shows the results.
 
Concentration of antibiotic in mg/dm3	Diameter of clear area in mm	
0	0	
1	0	
3	8	
5	15	
10	16	
20	17	
(d)     What was the dependent variable in this investigation?
___________________________________________________________________
___________________________________________________________________
(1)
(e)     Calculate the area where bacteria were killed when the antibiotic concentration was 20 mg/dm3
Use the equation: area = πr2
Use 3.14 as the value for π
r is the radius of the circle.
Give your answer to 3 significant figures.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
Area = ____________________ mm2
(2)
(f)      The scientists recommended that the antibiotic should be used at a concentration of 5 mg/dm3
Suggest two reasons why the scientists recommended this concentration.
1. _________________________________________________________________
___________________________________________________________________
___________________________________________________________________
2. _________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(2)
(g)     The antibiotic needs further testing before it can be licensed for human use.
The first stage is pre-clinical tests using live cells, tissues and animals.
Describe the other stages of drug testing.
Give reasons for each stage.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(6)
(Total 16 marks)

Mark schemes
Q1.
(a)  any one from:
•   plasmid
do not accept nucleus
•   chromosome
•   DNA / genes
allow alleles
allow genetic material
1
(b)  no clear area (around C and E)
1
(so) no bacteria killed (by antibiotic)
allow (so) antibiotic did not work
1
if no letters are given assume they are referring to antibiotics C and E
(c)  increased the concentration of antibiotic
allow increased the dose of antibiotic
ignore increased the volume of antibiotic
ignore left it longer
ignore used a different temperature
ignore used a different sized disc
1
clear area seen (around disc)
or
bacteria (around disc) killed
mark dependent on describing a change to the method
1
(d)  the treatment injected around the implant
1
(e)  any one from:
ignore reference to cost
(stem cells from fat tissue)
•   easier to obtain
allow quicker to obtain
•   less invasive
allow fewer side effects
allow less painful
ignore reference to rejection
1
(f)   by diffusion
no marks if incorrect process selected
1
concentration of antibiotic lower inside cells than in solution
or
concentration of antibiotic higher in solution than inside cells
allow 'it' for antibiotic
allow correct reference to concentration gradient
1
(g)  0.09 to 0.31
allow 0.31 to 0.09
1
(h)  any two from:
Pros:
stem cells containing antibiotic had:
•   smallest area of infection (: total tissue area)
•   small(est) range of results
•   no overlap with unreactive solution (suggesting significant effect)
2
any two from:
Cons:
•   only tested on 5 patients
allow small sample size
•   some results for antibiotic treatment similar to stem cells containing antibiotic
•   some results for stem cell treatment similar to stem cells containing antibiotic
•   age / health of patients not controlled
•   only tested on one type of bacterium
ignore only tested on one infection
•   only tested on one type of implant
•   only collected results after 7 days
•   may lead to antibiotic resistance (in S. aureus bacteria)
•   rejection of stem cells
•   need donors for stem cells
•   allergic reaction to antibiotic
ignore cost
ignore religion
ignore use of embryonic stem cells
ignore references to viruses
ignore side effects unqualified
2
[14]
Q2.
(a)
 
do not accept more than one line from a box on the left
1
1
1
(b)  reduces breeding / reproduction (in mosquitos)
allow fewer (mosquito) eggs fertilised
allow no offspring produced (by sterile mosquitos)
1
(so) fewer mosquitos to bite people
or
(so) fewer mosquitos to pass on pathogen / protist
allow (so) less likely to be bitten by mosquitos
ignore fewer mosquitos to pass on malaria / disease
1
(c)  electron microscope
ignore microscope unqualified
ignore scanning / transmission
do not accept light microscope
1
(d)  (fungal spore)
(16 µm =) 1.6 × 10-5 m
or
(virus)
(2.5 × 10-7 m =) 0.25 µm
1

or

allow incorrect attempt at conversion or not converted value for length correctly substituted
1
(=) 64
allow a correctly calculated value using an incorrectly or not converted value for length
allow 1 mark only for 
1
(e)  discolouration in leaves
or
less chlorophyll in leaves
the idea of less is only needed once
ignore mosaic pattern of leaves unqualified
1
(so) reduced photosynthesis
allow less light absorbed
1
(so) less glucose produced so less amino acids / proteins / cellulose made
allow (so) less glucose so less energy for synthesis of chemicals
or
allow (so) less glucose for respiration (so) less energy transferred for growth
1
[12]
Q3.
(a)  any four from:
•   bacterial cell is smaller (than a plant cell)
allow converse statements ‘it’ refers to bacteria
•   bacterial cell does not have chloroplasts (plant cell does)
ignore chlorophyll
•   bacterial cell does not have its DNA / genetic material inside a nucleus (plant cell does)
allow bacterial cell does not have a nucleus (plant cell does)
allow bacterial cell has DNA / genetic material in a ring / loop (plant cell does not)
allow bacterial cell has DNA / genetic material free in cytoplasm
•   bacterial cell (may) have plasmids (plant cell does not)
•   bacterial cell does not have mitochondria (plant cell does)
•   cell wall in bacterial cells is not made of cellulose (cell wall in plant cells is)
•   bacterial cell does not have a large / permanent vacuole (plant cell does)
•   bacterial cell has smaller ribosomes (than plant cells)
do not accept idea that bacterial cells do not have ribosomes
allow bacterial cell (may) have a flagellum (plant cells do not)
allow bacterial cell (may) have a slime capsule (plant cell does not)
4
(b)  any four from:
•   dead / inactive / weakened form of pathogen / bacterium / microorganism is introduced / injected
allow introduce / inject antigen(s) from the pathogen
allow dead / inactive / weakened form of Gonorrhoea (bacteria) introduced / injected
do not accept inject Gonorrhoea disease
•   white blood cells stimulated to produce antibodies
do not accept incorrect white blood cell, eg phagocyte
•   reference to memory cells made or remain
•   on re-exposure specific / correct antibodies are made (very) quickly
allow on re-exposure specific / correct antibodies are produced in large quantities
•   bacteria / pathogens / microorganisms killed and do not produce a large enough population to cause the disease
allow bacteria / pathogens / microorganisms killed and do not produce a large enough population to produce toxins
4
(c)  fewer bacteria / pathogens in chicken / eggs / food
ignore references to immunity unqualified
allow fewer chickens / eggs will carry the bacteria / pathogens ignore chickens do not get disease / infected
1
(so) fewer bacteria are ingested (by humans)
allow idea of fewer bacteria being passed on to humans in food
or
fewer bacteria / pathogens ingested (by humans) (1)
(so) fewer toxins produced (1)
allow idea of fewer bacteria being passed on to humans in food (1)
1
(d)  wash hands before preparing food
ignore wash hands unqualified
allow good food hygiene
wash hands after using the toilet
allow clean areas where a person has been ill
allow do not shake hands (with someone who has food poisoning)
1
(e)  warmer weather so bacteria reproduce / increase faster
ignore bacteria are killed at low temperatures
allow food not cooked properly on barbeques
1
[12]
Q4.
(a)  3 years
1
(b)  any one from:
•   to reduce any risk
allow idea (if it is unsafe) less harm will be caused with a lower dose
ignore that it may be unsafe / dangerous unqualified
•   to look for side effects
ignore unknown side effects unqualified
1
(c)  too great a risk for ill person / patient
allow may make their condition worse
allow less risk to healthy person
ignore references to immune system
1
patient might be taking another drug
allow unhealthy person might be taking another drug
or
side effects of drug are easier to identify
ignore to see side effects unqualified
1
(d)  any one from:
•   to prevent false claims
•   to make sure the results / conclusions are correct / valid
ignore references to accuracy, reliability or precision
•   to avoid bias
1
(e)  Level 3: A judgement, strongly linked and logically supported by a sufficient range of correct reasons, is given.
5−6
Level 2: Some logically linked reasons are given. There may also be a simple judgement.
3−4
Level 1: Relevant points are made. They are not logically linked.
1−2
No relevant content
0
Indicative content
arguments for use:
•   will save the NHS money
•   (approximately) 20 times as many people or 19 more people can be treated compared to Drug A
•   (approximately) 29 times as many people can be treated compared to Drug B (allow 28 times or 28 / 27 more people)
•   more people can be treated for the same cost
•   patients will be treated sooner
•   improves patient choice
•   used in other countries so likely to be effective
•   used in other countries so likely to be safe
•   likely to have been tested in other countries
arguments against use:
•   injections of drug not tested (in UK)
•   cannot be sure it is as effective as Drug A / Drug B
•   cannot be sure if it is safe to use
•   may have unknown side effects
•   doctors cannot be confident in prescribing Drug C
•   goes against regulations / laws regulating drug development / use
•   might set a precedent for other drugs not to be fully tested
•   might set a precedent for other non- approved / unlicensed drugs to be used
Need advantages and disadvantages for Level 2
[11]
Q5.
(a)     0.67(%)
allow  
allow 1 mark for evidence of (2 × 106) ÷ (3 × 108)
or
allow 1 mark for 0.0067 or 0.6
2
(b)     (i)      idea that food chains start with plants / producers
allow food chains do not start with animals or larvae are consumers
1
idea that these make food (for other organisms in the chain)
allow idea that plants / producers photosynthesise or plants / producers get energy from the sun
allow mosquito larvae do not make food / photosynthesise or mosquito larvae do not get energy from the sun
1
(ii)     any four from:
•        reasoned argument for or against release
must refer to at least one advantage and one disadvantage.
max 3 marks for either only advantages or only disadvantages
advantages:
•        fewer mosquitos biting or spreading malaria
•        fewer people get / die from malaria
allow people won’t get / die from malaria
•        lower medical costs (for those infected or for treatment) or less healthcare needed
•        better economically for developing / tropical countries.
disadvantages:
•        fewer crops reproduce
allow fewer crops pollinated
•        poorer crop yield
•        possible starvation (of people)
•        high cost of GM production / mosquito release
•        less food for bats / birds or bats / birds die
allow disruption to food chain / ecosystem or reduction of biodiversity
•        gene could ‘escape’ into other wildlife / species
ignore into plants
4
(iii)     any three from:
•        gene from bacteria cut out
allow allele for gene
•        ref to enzymes (anywhere in process)
allow at any point in process, ie in cutting or in splicing
•        (gene) transferred to chromosome of mosquito
allow DNA for chromosome
•        at an early stage of development
allow egg / embryo
3
[11]
Q6.
(a)  protist
1
(b)  any two methods with reason from:
1 mark for method and 1 mark for a correctly linked reason
•   Method: insecticides
Reason: to kill mosquitos / vector
ignore kill insects unqualified
•   Method: (mosquito) nets
Reason: to avoid being bitten
allow long clothing
ignore acts as a physical barrier
•   Method: insect repellents
Reason: less likely to be bitten
allow DEET or named insect repellent
•   Method: vaccination
Reason: so people are immune (to malaria)
•   Method: anti-malaria tablets
allow named anti-malarial e.g. Larium / Malarone
allow antibiotics
•   Reason: kills the pathogen / protist
allow ecf from part (a)
ignore kills malaria
allow
Method: drain swampy ground
or
remove pots of water
or
put oil on water / pond
Reason: fewer breeding grounds for mosquitos
allow
Method: release GM / sterile mosquitos
Reason: prevent / reduce reproduction
if no other marks awarded allow 1 mark for kill mosquitos
4
(c)  any two from:
(bacterial cell):
does not have a nucleus
allow DNA is free in cytoplasm
allow has a single loop of DNA
allow has a single strand of DNA
has plasmids
allow description, e.g. (small) ring(s) of DNA
is smaller
allow bacterial cells do not have mitochondria or do not have membrane bound organelles
allow bacteria have smaller ribosomes
ignore bacterial cells do not have chloroplasts
2
(d)  to allow air / oxygen in for bacteria to respire
allow to allow carbon dioxide produced in respiration to escape
or
so bacteria can respire aerobically
1
(e)  (A)
(no change in population size) because no / limited cell division / reproduction
allow (no change in population size) because bacteria / cells adjusting to environment / culture conditions
ignore reference to growth unqualified
1
(B)
(rapid increase in population size) as cells dividing rapidly as (plentiful) supply of nutrients / food
allow rapid binary fission as (plentiful) supply of nutrients / food
1
(C)
(population size stays the same) as rate of cell death equals rate of cell division
1
(D)
(population size decreasing) as cells dying due to nutrients running out
or
(population size decreasing) as cells dying due to toxins / carbon dioxide / cell wastes building up (in solution)
1
(f)
a ratio of 30 000:1 for X and 0.55:1 for Y scores 3 marks
(SA: vol ratio of X =)
2.4 × 10-7 : 8 × 10-12
1
or
0.000 000 24 : 0.000 000 000 008
(SA: vol ratio of Y =) 726:1331
conversion to same scale: 30 000:1 and 0.55:1
if no other calculation marks awarded allow 1 mark for calculation of SA for X and Y
or
calculation of volume for X and Y
1
or
calculation of SA and volume for one or both cubes if not given as a ratio
1
(so) diffusion distance is longer in multicellular organism
allow converse
or
(so) volume supplied by each unit of surface area is greater in multicellular organism
allow converse
allow idea that some cells will have no surfaces exposed to outside in multicellular organism
1
(so) diffusion rate per unit volume is slower in a multicellular organism
allow converse
1
[17]
Q7.
(a)     any one from:
•        not all deaths recorded
•        not all causes of deaths recorded
allow cause may not be known
1
(b)     antibiotics do not kill viruses
allow antibiotics only kill bacteria
1
(c)     
 
all correct for 2 marks
1 or 2 correct for 1 mark
2
(d)     any one from:
•        to prevent false claims
•        to make sure the conclusions are correct / valid
•        to avoid bias
1
(e)     some people would be immune to EVD
allow those vaccinated would not contract the disease
1
if less people (in a population) have EVD less chance of it being passed on
1
(f)     Level 3 (5–6 marks):
A detailed and coherent evaluation is provided which considers a range of arguments for and against the use of unlicensed drugs and comes to a conclusion consistent with the reasoning.
Level 2 (3–4 marks):
An attempt to give arguments for and against the use of unlicensed drugs is made. The logic may be inconsistent at times but builds towards a coherent argument.
Level 1 (1–2 marks):
Discrete relevant points made. The logic may be unclear and the conclusion, if present,
may not be consistent with the reasoning.
0 marks:
No relevant content
Indicative content
pros
•        might save some lives
•        vaccine could reduce chance of future outbreaks
•        patient made aware of risk and agreed to use of drug
•        sharing of results could speed up development of effective vaccines / drugs
•        used mainly for health workers who were risking their lives to help
cons
•        could be dangerous
or
vaccine could harm a healthy person
•        goes against legislation / laws governing drug development
•        might set a precedent for other drugs not to be fully tested
•        unfair as not available to the African people
a justified conclusion
6
[13]
Q8.
(a)  any one from:
•   not everyone would go to the doctor
allow not all cases recorded
allow only medically confirmed cases recorded
ignore some cases are unknown
•   sample will not always be sent for analysis
•   some cases not tested / diagnosed / confirmed
allow idea that doctor may make a judgemental error or mis-diagnosis
1
(b)  
allow for 1 mark:
 
1
96 / 95.5
allow 2 marks for correct rounding of 95.51724138
allow 1 mark for correct calculation using incorrect subtraction only if working shown
1
an answer of 96 / 95.5 scores 2 marks
allow 1 mark only for 95 or other incorrect rounding
(c)  most people are immune so do not become ill (from infection)
allow herd / community immunity so do not become ill (from infection)
allow most people are immune so do not become infected
ignore most people are immune so don’t get / catch it
1
less chance of non-immune / unvaccinated individuals being exposed to pathogen / measles / virus
reference to an organism is needed
allow ‘it’ for the measles virus
allow fewer people to pass it on to non-immune people
1
(d)  Level 3: Relevant points (comparisons / reasons) are identified, given in detail and logically linked to form a clear account.
5−6
Level 2: Relevant points (comparisons / reasons) are identified and there are attempts at logical linking. The resulting account is not fully clear.
3−4
Level 1: Points are identified and stated simply, but their relevance is not clear and there is no attempt at logical linking.
1−2
No relevant content
0
Indicative content
differences (after exposure to measles virus):
•   greater number / higher concentration of antibodies produced
•   quantitative statement, e.g. 9 times higher or 0.8 to 7.2
•   antibodies produced sooner − idea of immediate response
•   antibodies produced quicker
•   antibodies stay (in higher concentration) for longer
explanation
•   white blood cells / leucocytes / lymphocytes / B cells
    ignore phagocytes / macrophages
•   reference to previous exposure (of white blood cells) to pathogen / virus
•   (white blood cells) recognise pathogen / virus / antigen
•   memory cells
•   production of specific / correct antibodies
[11]
Q9.
(a)     (1 572 189 × 3 467) / 100 000
1
54 507.79263 or any correct rounding
1
54 508
an answer of 54 508 scores 3 marks
1
(b)     to control for the different (group) population sizes
allow so the different groups can be compared
1
(c)     thick yellow / green discharge from penis / vagina
and
pain on urinating
allow any two correct symptoms
1
(d)     diameter of clear area
1
(e)     3.14 × 8.5 × 8.5
1
227
allow 226.865 or any correct rounding for max 1 mark
an answer 227 scores 2 marks
1
(f)     comment relating to data, eg higher concentrations did not show much improvement
or
5 mg/dm3 was much more successful at killing bacteria than at lower concentrations
1
comment relating to patient safety eg much less likely to cause toxic / side effects than at higher concentrations
1
(g)     
Level 3: Relevant points (correct stages / reasons) are identified, given in detail and linked logically to form a clear account.	5-6	
Level 2: Relevant points (correct stages / reasons) are identified and there are attempts at logical thinking. The resulting account is not fully clear.	3-4	
Level 1: Points are identified and stated simply, but their relevance is not clear and there is no attempt at logical thinking.	1-2	
No relevant content	0	
Indicative content
names of stages are not required, but a logical progression through stages of testing is required for Levels 2 and 3.
phase 1 clinical testing:
•   tested on healthy volunteers
•   low doses used
reason:
•   to test for side effects / toxicity / safety
phase 2 clinical testing:
•   tested on patients
•   patients given placebo or drug
•   double blind trial
reason:
•   to test for side effects / toxicity / safety
•   to test its efficacy / effectiveness
phase 3 clinical testing:
•   larger numbers of patients used
•   patients given placebo or drug
•   double blind trial
reason:
•   to verify efficacy / effectiveness
•   to determine correct dose
prior to licensing:
•   analysis of results
•   peer review
reason:
•   to check results are valid
•   to avoid bias	 	
6
[16]