Question 1: Define the term 'antibiotic'.

Answer: A substance produced by microorganisms or synthetically that kills or inhibits the growth of bacteria.

Question 2: Explain how antibiotics selectively target bacteria without harming human cells.

Answer: Antibiotics target specific features of bacterial cells, such as cell wall synthesis or protein production, which are different from human cells, thus minimising damage to human tissues.

Question 3: Describe the mechanism by which penicillin kills bacteria.

Answer: Penicillin inhibits the formation of bacterial cell walls by blocking enzymes involved in peptidoglycan synthesis, causing the bacteria to burst due to osmotic pressure.

Question 4: Calculate the number of bacteria remaining after 3 hours if an antibiotic reduces the bacterial population by 90% every hour, starting with 10,000 bacteria.

Answer: 1000 bacteria remaining after 3 hours.

Question 5: Identify two factors that can influence the effectiveness of antibiotics.

Answer: The bacterial strain's resistance genes, The type of antibiotic used.

Question 6: Fill in the blank: Overuse and misuse of antibiotics can lead to the development of __________ bacteria that are resistant to treatment.

Answer: antibiotic-resistant

Question 7: Describe a simple experiment to test the effectiveness of a new antibiotic against bacteria in a laboratory setting. Include variables and safety precautions.

Answer: Set up agar plates inoculated with bacteria. Apply the antibiotic to one section of the plate while leaving another section as control. Variables include the type of bacteria and concentration of antibiotic. Precautions include wearing gloves, sterilising equipment, and disposing of waste safely. Observe zones of inhibition where bacteria do not grow to assess effectiveness.

Question 8: A bacterial culture shows a 50% reduction in growth after exposure to an antibiotic. What could this suggest about the bacteria's resistance or the antibiotic's effectiveness?

Answer: It suggests that the bacteria may be partially resistant or that the antibiotic is only partially effective against that strain.

Question 9: Explain why antibiotics are not effective against viral infections.

Answer: Antibiotics target features specific to bacteria, such as cell walls or protein synthesis, which viruses do not have. Viruses replicate inside human cells and lack these structures, so antibiotics cannot affect them.

Question 10: Discuss the impact of antibiotic resistance on modern medicine and suggest one strategy to minimise its development.

Answer: Antibiotic resistance can render common infections difficult or impossible to treat, leading to higher mortality rates. To minimise resistance, strategies include responsible prescribing, completing courses of antibiotics, and investing in research for new medicines.

Question 11: In everyday life, why is it important to follow medical advice when prescribed antibiotics?

Answer: Following medical advice ensures the full course is completed, preventing bacteria from surviving and developing resistance.