Question 1: Define the term 'fungus' and explain its main characteristics.

Answer: A fungus is a eukaryotic organism that absorbs nutrients from its environment, has a cell wall made of chitin, and reproduces via spores.

Question 2: Describe the typical mechanism by which fungi infect human tissues.

Answer: Fungi infect tissues by attaching to skin or mucous membranes, penetrating the outer layers, and invading cells using enzymes, often producing spores that spread the infection.

Question 3: Explain why fungi are classified as eukaryotes and how this affects their susceptibility to antifungal treatments.

Answer: Fungi are eukaryotes because they have membrane-bound organelles and a nucleus, which makes certain drugs targeting cell division or membrane synthesis effective against them.

Question 1: A fungal culture grows at a rate of 0.5 mm per hour. How far will the fungus have grown after 24 hours? (Show your calculation.)

Answer: Growth = rate × time = 0.5 mm/hr × 24 hr = 12 mm.

Question 2: If a sample of fungal spores has a resistance rate of 0.02 to a specific antifungal drug, how many spores out of 10,000 are likely resistant? Show your work.

Answer: Resistant spores = total spores × resistance rate = 10,000 × 0.02 = 200 spores.

Question 1: Describe a basic experimental setup to test the effectiveness of a new antifungal agent against a fungal culture, including variables to control.

Answer: Set up petri dishes with fungal cultures, apply the antifungal agent to some, leave others as controls, and measure fungal growth zones. Control variables include temperature, inoculum size, and incubation time.

Question 2: List two safety precautions to follow when handling pathogenic fungi in a laboratory.

Answer: Wear protective gloves and work in a sterile environment to prevent infection and contamination.

Question 1: A study reports that, in a resistant fungal population, the average resistance rate to a drug is 0.15. What does this imply about the proportion of resistant spores in the population, and what are the implications for treatment?

Answer: A resistance rate of 0.15 indicates that 15% of spores are resistant, which can lead to reduced effectiveness of the drug and necessitate alternative treatments or combination therapies.

Question 1: Explain the role of enzymes in the pathogenicity of fungi and how this knowledge can be used to develop antifungal drugs. (6 marks)

Answer: Fungi produce enzymes like proteases and lipases that break down host tissues, aiding invasion. Understanding these enzymes allows for the development of drugs that inhibit their activity, reducing fungal virulence and infection severity.

Question 1: Describe how fungi are used in the production of antibiotics, giving an example of a commonly used antibiotic derived from fungi.

Answer: Fungi such as Penicillium produce antibiotics like penicillin, which inhibit bacterial cell wall synthesis and are used to treat bacterial infections.

Question 2: Explain the significance of fungi in the food industry, providing two examples.

Answer: Fungi are used in food production to make bread (yeast fermentation) and cheese (mould ripening), contributing to flavour and texture.