Infection and Response Worksheet - GCSE - Intermediate

Infection and Response worksheet for GCSE (Key Stage 4 / GCSE (Ages 14-16)). Intermediate level science practice, aligned to the UK National Curriculum. Print-ready with answer key included.

Science•Key Stage 4 / GCSE (Ages 14-16)•Infection and Responseintermediate

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Infection and Response: Pathogens, Defences and Medicines

GCSE Biology | Ages 14–16 | Intermediate

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Instructions: Complete all six activities using precise scientific vocabulary. Show calculations where needed and use evidence from the data provided. For the extended response, organise your points into a clear, evidence-based explanation.

Pathogens and Disease

Answer each question in a concise sentence or phrase. Distinguish carefully between the different pathogen groups and explain how infection can spread.

1. Name the type of pathogen that reproduces only inside living host cells.

2. Which type of pathogen can produce toxins that damage tissues?

3. Give one example of a disease caused by a fungus.

4. Describe one way a pathogen can spread from one person to another.

The Human Immune Response

Use accurate terms for the cells and molecules involved. Explain the role of antibodies and memory cells rather than simply naming them.

1. Which type of white blood cell engulfs and digests pathogens?

2. What do antibodies bind to on a pathogen?

3. Explain how memory cells help the body respond more quickly to a second infection by the same pathogen.

4. Name the protein-based molecules that can neutralise toxins released by pathogens.

Vaccination and Population Data

Read the table carefully before answering. Use figures from the table to support your comparisons, and calculate the difference in cases.

Year	People vaccinated (%)	Reported cases
1	60	120
2	80	60
3	95	15

1. How many reported cases were recorded in Year 1?

2. Calculate the decrease in reported cases from Year 1 to Year 3.

3. Describe the relationship between vaccination coverage and reported cases in this data.

4. Explain how vaccination can reduce the spread of a disease through a population.

Antibiotics and Resistance

Apply your knowledge to the situations below. Remember that antibiotics act against bacteria, not viruses, and that resistance can spread through bacterial populations.

1. Explain why antibiotics are not an effective treatment for a common cold caused by a virus.

2. A bacterial infection is treated with an antibiotic. Explain how resistant bacteria may become more common over time.

3. Give one reason why a patient should follow the instructions for an antibiotic course prescribed by a clinician.

4. State one action that can help slow the development or spread of antibiotic-resistant bacteria.

Developing and Testing New Drugs

Use the information in each question to explain the purpose of drug testing. Include the relevant stages and scientific terms.

1. What is the purpose of preclinical testing before a new drug is tested on people?

2. In a clinical trial, why may some participants receive a placebo?

3. Explain why a new medicine is tested on a small number of healthy volunteers before larger trials involving patients.

4. State one benefit of a double-blind trial.

Extended Response: Vaccines and Antibiotics

Write one organised response. Explain the biological processes involved, compare the roles of vaccination and antibiotics, and use scientific vocabulary. Support your points with relevant examples.

Explain how vaccination protects individuals and can reduce disease transmission in a population. Compare this with the role of antibiotics in treating bacterial infections, and explain why antibiotics do not treat viral infections. [6 marks]

Answer Key

Activity 1: 1. Virus ; 2. Bacterium (bacteria) ; 3. Athlete’s foot or ringworm ; 4. For example, droplets from a cough or sneeze, contaminated food or water, direct contact, or an infected vector

Activity 2: 1. Phagocyte ; 2. Antigens ; 3. Memory cells remain after the first infection and enable a faster, larger production of the specific antibody if the same pathogen enters again ; 4. Antitoxins

Activity 3: 1. 120 ; 2. 105 cases ; 3. As vaccination coverage rises from 60% to 95%, reported cases fall from 120 to 15 ; 4. Vaccinated people develop immunity, so fewer people can become infected and pass the pathogen on, reducing transmission and helping protect people who are not immune

Activity 4: 1. Antibiotics target bacterial structures or processes; viruses reproduce inside host cells and are not affected by antibiotics ; 2. Some bacteria have resistance mutations; the antibiotic kills susceptible bacteria, while resistant bacteria survive, reproduce and pass on resistance, increasing the proportion that is resistant ; 3. To use the medicine as prescribed and help treat the infection effectively while reducing the chance that surviving bacteria contribute to resistance ; 4. For example, use antibiotics only when prescribed and appropriate, follow the clinician’s directions, or improve infection prevention and control

Activity 5: 1. To check for toxicity, efficacy and suitable dosage, initially using cells, tissues and animals where appropriate ; 2. To provide a comparison that helps identify whether changes are caused by the medicine rather than expectation or other factors ; 3. To assess safety and appropriate dosage in a small group before exposing more people, including patients, to the medicine ; 4. Neither participants nor clinicians know who receives the medicine or placebo, reducing bias in reporting or assessment

Activity 6: A strong response explains that a vaccine contains antigens from a pathogen, prompting white blood cells to produce specific antibodies and memory cells without causing the disease. On later exposure, memory cells produce antibodies rapidly; vaccination also reduces the number of susceptible people and can lower transmission. Antibiotics treat bacterial infections by killing bacteria or preventing their growth, but do not treat viruses because viruses reproduce inside host cells and lack the bacterial targets antibiotics act on. Credit accurate explanation, comparison and relevant scientific vocabulary.