Question 1: Bacteria are microscopic single-celled organisms that can cause infections but also have beneficial roles. Describe two beneficial functions of bacteria in the environment.

Answer: Nitrogen fixation in soil and decomposition of organic material

Question 1: Define a bacterium and explain how bacteria reproduce.

Answer: A bacterium is a single-celled organism without a nucleus that reproduces mainly through binary fission, where one cell divides into two identical cells.

Question 2: Describe the role of a bacterial cell wall in maintaining its shape and protection.

Answer: The cell wall provides structural support, maintains shape, and protects the bacterium from environmental stresses.

Question 1: A bacterial culture starts with 1,000 bacteria. If the population doubles every 20 minutes, how many bacteria will there be after 2 hours? (Use the formula: N = N0 × 2^n, where N0 = initial number, n = number of doubling periods).

Answer: 16000

Question 1: Describe a basic experimental setup to test the effectiveness of an antibiotic against bacteria. Include the variables you would control and the safety precautions you should take.

Answer: Set up petri dishes with bacterial cultures, apply different concentrations of antibiotic, keep conditions constant (temperature, nutrient medium), control variables such as incubation time, and wear protective equipment to prevent contamination and infection.

Question 1: A researcher measures the growth of bacteria in two different environments over 24 hours. In Environment A, the bacterial population increases from 500 to 80,000. In Environment B, it increases from 500 to 20,000. What does this data suggest about the conditions in the two environments?

Answer: Environment A supports faster bacterial growth, possibly due to more favourable conditions such as optimal temperature, nutrients, or pH.

Question 1: Explain how antibiotics work to kill bacteria and discuss two factors that can lead to antibiotic resistance.

Answer: Antibiotics target specific bacterial structures or functions, such as cell wall synthesis or protein production, to inhibit growth or kill bacteria. Resistance develops when bacteria mutate or acquire genes that enable them to neutralise antibiotics or prevent their entry, often due to overuse or misuse of antibiotics.

Question 1: Discuss how bacteria are used in the industry to produce products such as insulin or antibiotics.

Answer: Genetically engineered bacteria are used to produce insulin for diabetes treatment and antibiotics by inserting specific genes into bacterial cells to produce these substances efficiently.