Question 1: Define protists and explain how some protists can act as pathogens.

Answer: Protists are a diverse group of single-celled organisms. Some protists act as pathogens by invading host organisms and causing diseases, such as the parasite Plasmodium which causes malaria.

Question 2: Describe the main mechanism by which the protist Plasmodium infects humans.

Answer: Plasmodium infects humans when an infected Anopheles mosquito transmits the parasite during a blood meal, leading to parasite entry into the bloodstream and liver cells.

Question 1: If a population of protist parasites reproduces at a rate of 3 times every 24 hours, how many protists will there be after 4 days if the initial population is 100?

Answer: Initial population = 100 Reproduction rate = 3 times per day Number of days = 4 Total population = 100 * 3^4 = 100 * 81 = 8,100

Question 2: A protist infection causes 150 new infected cells per hour. How many infected cells will there be after 12 hours?

Answer: 150 cells/hour * 12 hours = 1800 infected cells

Question 1: Describe a safe method to observe protists in a laboratory setting without risking contamination or infection.

Answer: Use sterile equipment, work in a clean environment, handle samples with gloves, and dispose of waste properly. Use microscopes with proper safety protocols.

Question 2: Identify the variables that should be controlled during an experiment measuring protist reproduction rates.

Answer: Temperature, pH, nutrient availability, light exposure, and initial population size should be controlled.

Question 1: A study reports that in a sample, the number of infected protist cells increased from 500 to 2000 over 3 days. Calculate the average daily growth rate assuming exponential growth.

Answer: Initial = 500, Final = 2000, Time = 3 days Growth factor = Final / Initial = 2000 / 500 = 4 Daily growth rate = (4)^(1/3) ≈ 1.587 Average daily growth rate ≈ 58.7%

Question 2: Based on the data, what could be a possible reason for the rapid increase in protist infection within this period?

Answer: The protists likely had favorable conditions such as optimal temperature, nutrient availability, or lacked predators, leading to exponential growth.

Question 1: Explain how the life cycle of Plasmodium contributes to its ability to infect humans and cause malaria. (6 marks)

Answer: Plasmodium has a complex life cycle involving both mosquitoes and humans. It begins when an infected mosquito bites a human, transmitting sporozoites into the bloodstream. These invade liver cells, multiply, and then infect red blood cells, causing symptoms. The cycle continues when another mosquito bites the infected person, ingesting the parasites, which then develop into infective forms within the mosquito, ready to infect another host.

Question 1: Discuss how understanding protist reproduction and infection mechanisms can aid in developing treatments for diseases like malaria.

Answer: Understanding protist reproduction helps identify stages to target with drugs. Knowledge of infection mechanisms can lead to the development of vaccines or inhibitors to block transmission or parasite multiplication, thereby reducing disease incidence.

Question 2: Describe a technological advancement that uses protists or their mechanisms for beneficial purposes in industry.

Answer: Genetic engineering of protists like algae is used to produce biofuels, pharmaceuticals, and food supplements, exploiting their rapid growth and metabolic pathways for sustainable industry applications.