6- other pathogenic agents

Question 1

Stem rust fungus on cereal crops (Puccinia graminis on wheat)- mode of transmission

Answer 1

• Spores are spread by wind from infected plants to susceptible hosts.
• Fungal spores can overwinter on plant debris.

Question 2

Stem rust fungus on cereal crops (Puccinia graminis on wheat)- mode of infection

Answer 2

• Fungus enters the plant through stomatal openings.
• The fungal hyphae grow
intercellularly and produce haustoria that penetrate the host cells to extract nutrients.

Question 3

Stem rust fungus on cereal crops (Puccinia graminis on wheat)- pathogenic effect

Answer 3

• Causes stem rust disease, shown by reddish-brown pustules on stems and leaves.
• Infected plants may have reduced growth, lower grain yield, and poor grain quality.

Question 4

influenza virus- mode of transmission

Answer 4

• Spread through tiny droplets made when people with the flu cough, sneeze, or talk.
• Can also be transmitted by touching a surface or object that has the virus on it and then touching the mouth, nose, or eyes.

Question 5

influenza virus- mode of infection

Answer 5

• Virus enters the body by the nose or mouth, and infects cells in the respiratory tract.
• The virus uses the host’s cellular machinery to replicate and produce more viruses.

Question 6

influenza virus- pathogenic effect

Answer 6

• Causes influenza.
• Symptoms include fever, cough, sore throat, body aches, headache, chills, and fatigue.
• In severe cases, it can lead to pneumonia and other complications.

Question 7

The malarial parasite (Plasmodium spp.)- mode of transmission

Answer 7

• Transmitted to humans via the bite of infected female Anopheles gambiae mosquitoes.
• The mosquito ingests the parasite when it takes a blood meal from an infected person.

Question 8

The malarial parasite (Plasmodium spp.)- mode of infection

Answer 8

• Parasites travel to the liver where they invade liver cells and multiply.
• Merozoites are released into the bloodstream where they invade red blood cells, multiply, and cause the cells to burst, releasing more parasites.

Question 9

The malarial parasite (Plasmodium spp.)- pathogenic effect

Answer 9

• Causes malaria, symptoms include fever, headache, and vomiting.
• Severe cases can lead to anaemia, hypoglycaemia, and cerebral malaria. It can be fatal.