Question 1: Bacteria are microscopic single-celled organisms that can cause infections. They have a cell wall, cell membrane, cytoplasm, and genetic material, but lack a nucleus. They can reproduce rapidly under suitable conditions.

Answer: Bacteria are microscopic single-celled organisms without a nucleus, having a cell wall, cell membrane, cytoplasm, and genetic material, capable of rapid reproduction.

Question 2: Describe the primary mechanism by which bacteria reproduce.

Answer: By binary fission, where a bacterial cell divides into two identical cells.

Question 1: Define 'pathogen' in the context of bacteria.

Answer: A pathogen is a microorganism, such as certain bacteria, that causes disease.

Question 2: Explain how bacteria can cause disease in humans.

Answer: Bacteria cause disease by invading the body, multiplying, and producing toxins that damage tissues or disrupt normal functions.

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? Show your calculation using the formula: N = N0 × 2^n, where N0 is the initial number, and n is the number of doubling periods.

Answer: N = 1000 × 2^6 = 1000 × 64 = 64,000 bacteria.

Question 1: Design a basic experiment to test the effectiveness of different disinfectants on bacteria. Identify the variables involved and safety precautions needed.

Answer: An experiment could involve applying different disinfectants to bacterial cultures and measuring bacterial survival. Variables include disinfectant type (independent), concentration, and contact time (controlled), with temperature and initial bacteria count held constant. Safety precautions include wearing gloves, eye protection, and working in a sterile environment to prevent contamination.

Question 1: A study measures bacterial count in contaminated water samples over time. Initial counts are 500 bacteria per mL. After 3 hours, counts increase to 4000 bacteria per mL. Describe the bacterial growth pattern and suggest possible reasons for this pattern.

Answer: The bacterial count shows exponential growth, likely due to favourable conditions such as temperature, nutrients, and absence of antibiotics, which allow rapid reproduction.

Question 1: Explain the role of antibiotics in controlling bacterial infections. Include how bacteria can develop resistance and the implications for treatment.

Answer: Antibiotics work by killing bacteria or inhibiting their growth. Bacteria can develop resistance through genetic mutations or acquiring resistance genes, which can render antibiotics ineffective. Resistance leads to longer illnesses, increased healthcare costs, and limit the options for treatment, highlighting the importance of responsible antibiotic use.

Question 1: Describe how bacteria are used beneficially in industry or technology, providing specific examples.

Answer: Bacteria are used in industry for producing antibiotics, yogurt fermentation, wastewater treatment, and bioremediation to clean up environmental pollutants.