Q1. the Body Defends Itself Against Pathogens

Kirk Balk Academy

Unit 3 – Vaccination and Antibiotic Resistance

Q1. The body defends itself against pathogens.

(a) Give three ways that white blood cells defend the body against pathogens.

Tick () three boxes.

Ingest pathogens /
Produce antibiotics /
Produce antibodies /
Produce antibodies /
Produce antitoxins /
Produce vaccines /
Stop pathogens entering the body /

(3)

(b) Bacterial infections can be treated with antibiotics.

Sometimes bacteria are resistant to antibiotics.

What does resistant to antibiotics mean?

......

(1)

(c) The bar chart shows how the percentage of strains of pneumonia bacteria that are resistant to four different antibiotics changed between 1995 and 1997.

(i) Which would have been the best antibiotic to use against pneumonia bacteria in 1995?

Write the correct answer in the box. / Antibiotic /

(1)

(ii) Calculate the change in the percentage of strains of pneumonia bacteria resistant to antibiotic W between 1995 and 1997.

Show clearly how you work out your answer.

......

Answer = ...... %

(2)

(iii) Suggest two possible reasons for this change in the number of strains of pneumonia bacteria resistant to antibiotic W.

1 ......

2 ......

(2)

(Total 9 marks)

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

......

(2)

(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.

......

(2)

(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.

......

(3)

(Total 7 marks)

Q3. MRSA strains of bacteria are causing problems in many hospitals.

(a) The diagram shows a hand-gel dispenser.

Hand-gel dispensers are now placed at the entrance of most hospital wards.

Explain why.

......

(2)

(b) Explain, as fully as you can, how MRSA strains of bacteria became difficult to treat.

......

(3)

(Total 5 marks)

Q4.People may be immunised against diseases using vaccines.

(a)(i) Which part of the vaccine stimulates the body’s defence system?

......

(2)

(ii) A person has been vaccinated against measles. The person comes in contact with the measles pathogen. The person does not catch measles.

Explain why.

......

(3)

(b) A man catches a disease. The man has not been immunised against this disease. A doctor gives the man a course of antibiotics.

The graph shows how the number of live disease bacteria in the body changes when the man is taking the antibiotics.

(i) Four days after starting the course of antibiotics the man feels well again.
It is important that the man does not stop taking the antibiotics.

Explain why.

Use information from the graph.

......

(2)

(ii) Occasionally a new, resistant strain of a pathogen appears.

The new strain may spread rapidly.

Explain why.

......

(3)

(Total 10 marks)

M1.(a)ingest pathogens

produce antibodies

produce antitoxins

deduct1 mark for each extra box ticked

(b)are not killed / affected (by antibiotic)

allow antibiotic does not work / does not cure

allow bacteria immune (to antibiotic)

allow infection not killed

ignore bacteria mutated

(c)(i)(antibiotic) Y

(ii) 8

allow 54 − 46 for 1 mark

(iii)anytwo from:

•overuse / widespread use/ over prescription

OWTTE

•inappropriate use / use for eg sore throats / viral infections

•mutation / change to DNA (in bacteria)

•natural selection /description

ignore people not finishing course of antibiotics

ignore wrong antibiotic given

[9]

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

viruses inaccessible to antibiotic

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

(ii)mutation

ignore mutation caused by antibiotic

natural selection or no longer recognised by antibiotics

accept description of natural selection

(b) (stimulate) antibody production

ignore antitoxin

(by) white cells

rapidly produce antibody on re-infection

ignore antibodies remain in blood

[7]

M3. (a)kills / destroys bacteria / MRSA

donot allow germs

prevents / reduces transfer

allow stops MRSA entering ward

(b) mutation

donot accept antibiotics causes mutation

(causes) resistance

allow not effective

ignore immunity

toantibiotics

[5]

M4. (a) (i) dead / inactive / weakened

allow antigen / protein

ignore ref to other components

ignore small amount

pathogen / bacterium / virus / microorganism

ignore germs / disease

(ii)antigen / antibiotic instead of antibody = max 2

white blood cells produce / release antibodies

accept lymphocytes / leucocytes / memory cells produce antibodies
do not accept phagocytes

antibodies produced quickly

(these) antibodies destroy the pathogen

allow kill
do not accept antibodies engulf pathogens

(b) (i) (live) bacteria still in body

ignore numbers

would reproduce

ignore mutation / growth

(ii)antibiotics / treatment ineffective or resistant pathogens survive

accept resistant out compete non-resistant

these reproduce

population of resistant pathogens increases

allow (resistant pathogens reproduce) rapidly

[10]

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