Question
Reflexes are simple responses that protect the body.
The pathway that nerve impulses travel along during a reflex is called a reflex arc.
(a) Letters A to G show the components of a reflex arc.
A stimulus
B motor neurone
C sensory neurone
D receptor cell
E response
F relay neurone
G effector
Put the components into the correct sequence. Two have been done for you.
(b) Impulses travel between neurones across a synapse.
Describe how impulses travel across the synapse from one neurone to another. [3]
(c) Drugs such as heroin restrict the movement of impulses across synapses. Users can become
addicted to heroin. When users stop taking heroin they may experience withdrawal symptoms.
(i) State two withdrawal symptoms that heroin users may experience.
1
2 [2]
(ii) Suggest why heroin abuse may increase criminal activity. [1]
(d) Heroin abuse may lead to HIV infection. There is currently no approved vaccine that prevents
the spread of HIV. Vaccination stimulates active immunity against specific pathogens.
(i) Explain how vaccination stimulates active immunity [4]
(ii) Explain what is meant by passive immunity. [2]
[Total: 13]
Answer/Explanation
Ans
2 (a) A D C F B G E
(b) 1 ref to chemical neurotransmitter ;
2 from/ in, vesicles / sacs ;
3 neurotransmitter diffuses ;
4 across synaptic cleft/gap ;
5 neurotransmitter binds with receptors ;
(c) (i) sleeplessness ;
hallucinations ;
muscle cramps /restless legs ;
nausea ;
vomiting ;
headaches ;
sweating ;
aggression/ agitation/restlessness / anxiety /mood swings / panic attacks ;
AVP ; e.g. shivering/ diarrhea
(ii) (addicts) turn to crime to finance their addiction/AW ;
more opportunity to become drug dealers / mule/ AW ;
(d) (i) 1 harmless /dead/weakened/ attenuated, (named) pathogen/ microorganisms ;
2 injected/ ingested ;
3 ref to antigens ;
4 antigen/ vaccine, triggers antibody production ;
5 by lymphocytes ;
6 memory cells are produced ;
7 long-term immunity /rapid immune response ;
(ii) 1 short-term defence against pathogens ;
2 no immune response/immediate protection/no memory cells produced/
no antibodies produced by the body ;
3 from antibodies, acquired from elsewhere/AW ;
4 e.g. across placenta/breast-feeding/ breast milk / colostrum/ antitoxin/
antivenom/ tetanus injection/ immunoglobulins ;
Question
Penicillin is an antibiotic.
(a) (i) Explain why doctors give antibiotics to people who are ill.
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………[2]
(ii) Explain why it is important to complete a full treatment of antibiotics.
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
(b) Penicillin was discovered in 1928 by Alexander Fleming.
Name the type of microorganism that produces the antibiotic penicillin.
……………………………………………………………………………………………………………………………..[1]
(c) Penicillin is produced commercially in fermenters as shown in Fig. 1.1.
(i) Describe how a fermenter can be sterilised.
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………[2]
(ii) Table 1.1 shows some names of the parts of the fermenter and their functions.
Complete Table 1.1.
One row has been done for you.
Answer/Explanation
Ans:
Question
Type 1 diabetes is caused by the immune system destroying body cells.
(a) (i) Suggest which organ in the body is attacked by the immune system to cause Type 1
diabetes.
………………………………………………………………………………………………………………………[1]
(ii) Antibodies are part of the immune system.
Describe how antibodies function.
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………[2]
(b) Humans need vitamin D as part of their diet.
(i) Describe a cause of vitamin D deficiency in humans.
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………[1]
(ii) Describe the effects of vitamin D deficiency in humans.
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………[2]
Scientists have found that mice can suffer from Type 1 diabetes. They also found that vitamin D
affects the development of Type 1 diabetes in mice.
Two groups of mice were studied. One group were normal and the other group were
vitamin D-deficient. The percentage of mice in each group that developed Type 1 diabetes was
recorded every fifty days.
Table 4.1 shows their results.
(c) Describe the effect of vitamin D deficiency on the development of Type 1 diabetes in mice.
Use the data in Table 4.1 to support your answer.
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………..[3]
(d) Suggest the symptoms that mice with Type 1 diabetes would have.
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………………..[4]
(e) Describe the treatment for human patients with Type 1 diabetes.
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
Answer/Explanation
Ans:
Question
The genes for antibodies are only active in lymphocytes.
(a) Define the term gene.
…………………………………………………………………………………………………………………………………
(b) Lymphocytes produce antibodies.
Outline the role of antibodies in the defence of the body against pathogens.
…………………………………………………………………………………………………………………………………
(c) Fig. 2.1 is a drawing made from an electron micrograph of a lymphocyte that produces
antibodies.
Table 2.1 contains statements about the structures visible in Fig. 2.1.
Complete Table 2.1 by
• naming the structure
• identifying the letter that labels the structure.
The first one has been done for you.
(d) State the name of one type of cell, other than a lymphocyte, that is involved in the defence of
the body against pathogens and describe its role.
name …………………………………………………………………………………………………………………………
role ……………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
Answer/Explanation
Ans:
Question
(a) The body has defence mechanisms to protect it from infection.
Outline the body’s defence mechanisms.
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………… [5]
(b) State the name of a type of drug that can be used to treat bacterial infections.
…………………………………………………………………………………………………………………………… [1]
Answer/Explanation
Ans:
Question
Fig. 6.1 is a diagram of the virus that causes measles.
(a) (i) State the name of the parts of the virus shown in Fig. 6.1 labelled X and Y.
X ……………………………………………………………………………………………………………………….
Y ……………………………………………………………………………………………………………………….
[2]
(ii) Bacteria belong to the Prokaryote kingdom.
State two ways in which the structure of bacteria differs from the structure of viruses.
1 ……………………………………………………………………………………………………………………….
2 ……………………………………………………………………………………………………………………….
[2]
(b) Viruses and some bacteria are pathogenic. Diseases caused by pathogens are transmissible.
(i) State two ways that a pathogen can be transmitted indirectly.
1 ……………………………………………………………………………………………………………………….
2 ……………………………………………………………………………………………………………………….
[2]
(ii) The body has barriers to defend itself against pathogens.
State two mechanical barriers of the body.
1 ……………………………………………………………………………………………………………………….
2 ……………………………………………………………………………………………………………………….
[2]
(c) Some white blood cells produce antibodies as part of the body’s defence against pathogens.
Describe the role of antibodies in defence of the body.
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………… [4]
(d) The immunity gained after infection by a pathogen is active immunity.
Explain how active immunity differs from passive immunity.
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………… [3]
Answer/Explanation
Ans:
Question
(a) Antibodies are proteins that are produced by lymphocytes. Antitoxins are antibodies which
neutralise the toxins released by some bacteria.
The transmissible disease diphtheria is caused by a bacterium that releases a toxin that can
cause serious damage to the body.
A person is suspected of having caught diphtheria.
At a clinic, the person is given an injection of antitoxin antibodies that provide protection
against the diphtheria toxin. She is also given an injection of the vaccine for diphtheria.
A few weeks later she is given a second injection of the diphtheria vaccine.
Fig. 6.1 shows the changes in concentration of the antitoxin antibodies and the antibodies
produced in response to the vaccine.
(i) Explain the advantage of giving the person an injection of antitoxin antibodies.
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
(ii) Explain how the two injections of the vaccine result in better protection against diphtheria
than the injection of antitoxin antibodies.
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
(b) Explain how antibodies protect the body against pathogens.
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
(c) Antibodies can travel through the body in the lymphatic system.
State two functions of the lymphatic system other than defence against disease.
1 ………………………………………………………………………………………………………………………………
2 ………………………………………………………………………………………………………………………………
Answer/Explanation
Ans: 
Question
(a) Describe the similarities and differences between marasmus and kwashiorkor.
similarities …………………………………………………………………………………………………………………
differences ………………………………………………………………………………………………………………..
(b) Researchers at a hospital recorded the total number of children admitted to the hospital
between 1984 and 2002.
A common reason for children being admitted to this hospital was severe diarrhoea.
Table 4.1 shows this information.
(i) Calculate the percentage decrease in the total number of children admitted to the hospital between 1998 and 2002.
Give your answer to the nearest whole number.
Space for working.
…………………………………………………… %
(ii) Health workers in the communities near the hospital were trained in the prevention and
treatment of diarrhoea. This affected the total number of children being admitted to the
hospital.
Suggest the year in which the training took place.
Give a reason for your answer.
year …………………………………………………………………………………………………………………..
reason ……………………………………………………………………………………………………………….
(iii) The health workers provided advice to the community on ways of preventing the spread of the pathogens that cause diarrhoea.
Suggest the advice that was given to the community.
Answer/Explanation
Answer:
(a)
similarities, max 3 from:
both caused by protein (energy) deficiency ;
both types of malnutrition / deficiency disease / caused by lack of a
balanced diet ;
primarily affects children ;
diarrhoea ;
low body mass / weight loss ;
poor growth ;
irritability / tiredness ;
wastage of muscles ;
dry skin / brittle nails ;
brittle hair / change of hair colour ;
fatty liver ;
anaemia ;
AVP ;
differences:
kwashiorkor has water retention / oedema / swelling of body parts
/ pot belly ;
people suffering marasmus also deficient in, carbohydrates / fats
/ calories / energy ;
AVP ;
(b)
(i) 18 (%) ;;;
(ii) any year between 1990 and 1994 or from 2000 onwards ;
the number of children admitted to hospital decreases (after this
year) ;
(iii) 1 (described) hygienic food prep methods ;
2 washing hands / hand sanitisers ;
3 (description of use of) clean equipment ;
4 use of clean / boiled water / filtered water / pure water ;
5 (described examples of) disposal of waste correctly / idea of
where defaecation occurs / defaecation in a toilet ;
6 monitor or identify infective individuals;
7 isolate infected individuals ;
8
AVP ;
Question
Bacteria are classified as belonging to the Prokaryote kingdom.
(a) State two features of all prokaryotes.
1 ………………………………………………………………………………………………………………………………
2 ……………………………………………………………………………………………………………………………… [2]
MRSA is a type of bacterium that is resistant to antibiotics. The number of cases of MRSA identified in hospitals in the USA between 1995 and 2005 was recorded.
Fig. 2.1 shows these data.
Question
(b) (i) Describe the results shown in Fig. 2.1.
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………… [2]
(c) The number of cases of MRSA has decreased since 2005.
Suggest reasons for this decrease.
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………………… [2]
(ii) Explain how bacteria become resistant to antibiotics.
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
▶️Answer/Explanation
Ans:
(a)no nucleus ;
cell wall ;
loop of DNA ;
AVP ;;
(b)(i)
overall increase in number of cases of MRSA ;
largest increase, between 2004–2005 / exponential ;
data quote including the number of cases and the year/ data manipulation ;
(b)(ii)
1 correct ref to mutation of bacteria ;
2 variation in ability of bacteria to survive antibiotic treatment ;
3 bacteria with no /little resistance, die ;
4 bacteria with resistance, survive and breed ;
5 passing on resistant allele ;
6 ref to natural selection ;
7 AVP ; e.g. ref to strengthening of cell wall
(c)
more responsible use of antibiotics ;
improved, detection/ screening to avoid spread ;
ref to improved cleanliness ;
isolating infected patients ;
development of new antibiotics /treatment ;
Question
Viruses can cause diseases.
(a) (i) State two other features of all viruses.
1 ……………………………………………………………………………………………………………………….
2 ……………………………………………………………………………………………………………………….
(ii) Describe how vaccination can prevent the spread of disease.
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
(b) Fig. 6.1 shows four different viruses.
Suggest one feature that could be used to classify viruses into groups.
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
▶️Answer/Explanation
(a)(i)
genetic material ;
protein coat ;
parasitic / pathogenic ;
only reproduce in a host / do not show (other) features of living organisms / AW ;
very small ;
they are not cellular / absence of named organelle;
AVP ; cannot be killed / cannot be treated, with antibiotics.
(a)(ii)
active immunity ;
harmless / dead / weakened / attenuated pathogen / microorganisms ;
injected / ingested ;
ref. to antigens ;
(antigen) triggers antibody production ;
by lymphocytes ;
memory cells (are produced) ;
rapid response to reinfection ;
long-term immunity ;
prevention of spread person to person e.g. no host for pathogen / herd ref to programmes of mass vaccination ;
AVP ;
(b)
shape / size / AW ;
genetic material (sequence / type) ;
host species / type of disease it causes ;
AVP ;