Syllabus Edition

First teaching 2023

First exams 2025

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Antibiotics (CIE AS Biology)

Topic Questions

11 mark

Streptomycin, a type of antibiotic, is now less effective in treating TB worldwide.

Which of the following could be a reason for this? 

  • There is an increase in the number of people infected with drug-resistant strains.

  • The incidence of HIV infection is increasing, activating previously inactive Mycobacterium infections.

  • Fewer people are living in isolated rural areas and overcrowding occurs in inner cities.

  • Antibiotics such as streptomycin are not effective as antiviral drugs.

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21 mark

Some antibiotics are used in animal feed to help prevent disease.

Which statement explains why they should not be used to treat bacterial infections in humans?

  • Useful gut bacteria may be killed by these antibiotics.

  • Pathogenic bacteria may develop resistance to these antibiotics.

  • Human cells may stop responding to these antibiotics.

  • Humans may be allergic to these antibiotics.

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31 mark

When a patient is prescribed a course of antibiotics they must take them at evenly spaced intervals.

Why is this necessary?

  • To select and kill the resistant strains of bacteria.

  • To prevent the development of resistant strains of bacteria.

  • To maintain the concentration of antibiotic in the body which is lethal to the bacteria.

  • To increase the concentration of antibiotic slowly to a level that is lethal to the bacteria.

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41 mark

Which of these diseases are likely to be effectively treated with antibiotics?

  cholera TB malaria

A

B

C

D

X

X

X

X

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51 mark

Which of these diseases can be treated with antibiotics?

  • smallpox and cholera

  • cholera and tuberculosis

  • measles and smallpox

  • measles and tuberculosis

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6
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1 mark

Antibiotics work by interfering with several different processes in the target bacteria.

Which of the following is not a process which is impacted by antibiotic action?

  • Enzyme action

  • Formation of cell walls

  • Formation of capsid proteins

  • Protein synthesis

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7
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1 mark

Which of the following statements about antibiotic resistance is incorrect?

  • Antibiotic resistance occurs as a result of selection pressures provided by humans

  • Antibiotic resistance in bacteria is evidence to support Darwin’s theory of evolution by natural selection.

  • The development of antibiotic resistance in bacteria is an example of genetic drift.

  • The development of antibiotic resistance in bacteria is an example of directional selection.

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11 mark

The data below show the number of deaths due to Staphylococcus aureus from 1997 to 2005.

Methicillin is an antibiotic that is used to treat S. aureus infections. MRSA is methicillin-resistant S. aureus.

Year

total number of death certificates with S. aureus

total number of death certificates with MRSA

1997

1999

2001

2003

2005

369

452

456

420

428

355

431

681

890

1512

Which statement is not supported by this data?

  • S. aureus will always cause humans to die.

  • Resistant strains of MRSA are becoming more common

  • MRSA is more likely to lead to death than S. aureus.

  • More people have become infected with MRSA over time.

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21 mark

The diagram below shows how the effect of growing bacteria in the presence of an antibiotic can be investigated.

Five different types of bacteria were grown on their own petri dish, one example is shown below: Ks6JmdS8_diagram-1

The table below shows the results from testing the antibiotic on the growth of these five types of bacteria. Zones of inhibition less than 13 mm show the presence of resistant bacteria.

type of bacteria

diameter of zone / mm

Week 1

Week 2

Week 3

Week 4

Week 5

1

2

3

4

5

24.10

18.60

17.90

19.40

22.00

21.90

15.40

12.80

15.30

21.00

19.00

12.20

12.40

13.20

20.50

17.60

9.00

11.10

8.10

20.40

14.30

0.00

10.90

0.00

20.40

Which statement is supported by the data?

  • Bacteria type 5 can never become resistant to the antibiotic.

  • The antibiotic can be used to treat all five types of bacteria.

  • Only types 2, 3 and 4 of the bacteria showed resistance to the antibiotic.

  • Bacteria become more resistant over time.

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31 mark

The diagram shows the effect of growing Escherichia coli in the presence of streptomycin and penicillin.

screenshot-2023-05-14-232316

What can be concluded about the results?

  completely resistant not completely resistant
A S and P -
B P S
C S P
D - S and P

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41 mark

Some animals have evolved to produce small peptides called cathelicidins. These peptides have a bactericidal effect. They are able to attach to lipids in the bacterial membrane, thereby weakening them.

Synthetic versions of the cathelicidins have been produced. These can be used to treat infections that have become resistant to antibiotics like tetracycline.

Read the following statements:

1

The only way a bacterium could develop resistance to it is by altering all the lipids in its membranes.

2

Cathelicidins could be used instead of tetracycline, allowing tetracycline resistance to be reduced.

3

Cathelicidins are synthetic so bacteria can never become resistant to them.

4

Cathelicidins could be used to kill multidrug-resistant strains of bacteria, for which there are no currently effective antibiotics.

Which pair of statements explain how these peptides can help in the fight against antibiotic resistance?

  • 1 and 3

  • 1 and 4

  • 2 and 3

  • 2 and 4

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51 mark

Two species of bacteria A and B were grown on an agar plate. Each plate had three filter paper discs with the following:

1

no antibiotic (control)

2

penicillin V, a natural penicillin

3

carboxypenicillin, a synthetic penicillin

The diagram below shows the results:

screenshot-2023-05-14-232801

Which statement is a correct conclusion for this experiment?

  • Penicillin V is more effective than carboxypenicillin

  • Penicillin V is equally effective against A and B bacteria

  • Penicillin V and carboxypenicillin are both effective against bacteria A

  • Penicillin V is effective against bacteria B

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6
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1 mark

Lefamulin™ is a newly-developed antibiotic that binds to the 50S bacterial ribosomal subunit.

It was approved by the US Food and Drug Administration (FDA) in August 2019 for the treatment of pneumonia.

Which is the mode of action of Lefamulin™?

  • Inhibits bacterial protein synthesis

  • Perforates the bacterial cell membrane

  • Prevents the bacterial cell wall forming

  • Inhibits replication of bacterial DNA

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7
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1 mark

Which is a reason why fungi such as Penicillium have evolved to produce antibiotics?

  • To destroy bacteria that could otherwise feed on Penicillium

  • To destroy bacteria that could otherwise harm the fungus's host organisms

  • To destroy saprophytic bacteria as a way of Penicillium out-competing bacterial competitors for food

  • To kill viruses that may otherwise be pathogenic to the fungus

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11 mark

Which of these diseases can be cured with antibiotics?

q6-cie-10-2

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21 mark

Bacteria and viruses are the main pathogens in humans. Antibiotics can be used to treat bacterial infections but not viral infections.

Which of the following statements explains why?

  • Viruses need a host to survive.

  • Viruses consist of just nucleic acid and a protein coat.

  • Bacteria have peptidoglycan cell walls.

  • Viruses are significantly smaller than bacteria.

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31 mark

Antibiotics can interfere with aspects of growth or metabolism in bacterial cells. 

Which of the following is not a mode of action of antibiotics?

  • Preventing the synthesis of protein

  • Preventing enzyme action

  • Preventing DNA synthesis

  • Preventing the production of cellulose cell walls

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41 mark

Some bacteria have developed a resistance to penicillin.

Which of the following would explain how bacteria can prevent the action of penicillin?

  • production of mRNA

  • production of β-lactamase

  • production of peptidoglycan

  • production of phospholipids

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51 mark

An antibiotic sensitivity test was performed on bacteria isolated from a patient’s throat.

The diagram shows the results of the four antibiotics tested.

Which one should be used to treat the disease?

screenshot-2023-05-14-231433

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6
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1 mark

The graph below shows the number of deaths from MRSA per 100 000 people in a population of over-65’s from 2005 to 2012.

OFRaWUbT_image-4

Which of the following is the correct value of the average annual rate of decrease in the number of deaths from MRSA infections in the over-65s per 100 000 people from 2005 to 2012?

  • 1.14 deaths yr-1 per 100 000 people

  • 1.86 deaths yr-1 per 100 000 people

  • 0.71 deaths yr-1 per 100 000 people

  • 5.00 deaths yr-1 per 100 000 people

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7
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1 mark

The data in the graph shows the effect of an antibiotic on the population of bacteria in the blood.

aaI_~vWY_image-1

What can be concluded from the data in the graph?

  • Antibiotics take 10 days to kill all bacteria.

  • Antibiotics cause a reduction in division of bacteria.

  • Antibiotics are effective against viral and bacterial infections.

  • Before the start of the antibiotic treatment the bacterial population was increasing.

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8
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1 mark

Which of the following practices have contributed to the fall in antibiotic effectiveness in the late 20th and early 21st centuries?

  1. Large-scale use of preventative antibiotics in farm livestock
  2. Failing to complete the full course of antibiotics prescribed by a doctor
  3. Treatment of known bacterial infections with antibiotics
  4. Treatment of viral infections with antibiotics
  • All of them

  • 2, 3 and 4

  • 1 and 2

  • 1, 2 and 4

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