Pathogens

Question 1

What is a pathogen?

Answer 1

An organism that causes disease in another organism

Pathogens can include various groups of organisms.

Question 2

Name the groups of organisms that include pathogens.

Answer 2

• Bacteria
• Fungi
• Protoctists
• Viruses

Each group has distinct characteristics and effects on hosts.

Question 3

True or false: Pathogenic bacteria always infect the cells of hosts.

Answer 3

FALSE

Pathogenic bacteria can remain within body cavities or spaces.

Question 4

Give an example of a pathogenic bacterium and the disease it causes.

Answer 4

Pneumococcus, causing pneumonia

Pneumonia results in coughing, fever, and shortness of breath.

Question 5

Fungal diseases are much more common in plants than in animals. True or false?

Answer 5

TRUE

Some species of Mucor fungi are pathogenic.

Question 6

What protoctist causes severe forms of malaria in humans?

Answer 6

Plasmodium falciparum

The parasite is spread by mosquitoes.

Question 7

What are the biological characteristics shared by all viruses?

Answer 7

• Small particles (smaller than bacteria)
• Parasitic, reproduce inside living cells
• Infect every type of living organism
• No cellular structure, protein coat, one type of nucleic acid (DNA or RNA)

Viruses do not carry out the eight life processes independently.

Question 8

Name a virus that causes discolouration of leaves on tobacco plants.

Answer 8

Tobacco mosaic virus (TMV)

TMV prevents the formation of chloroplasts.

Question 9

What are the symptoms of tobacco mosaic virus?

Answer 9

Distinctive mosaic pattern of discolouration of leaves

This affects the plant’s growth and crop yield.

Question 10

How is tobacco mosaic virus spread?

Answer 10

• Direct contact with infected plants
• Soil can harbor the virus for about 50 years

Good field hygiene is essential for control.

Question 11

What does HIV stand for?

Answer 11

Human Immunodeficiency Virus

HIV can lead to Acquired Immunodeficiency Syndrome (AIDS).

Question 12

What are the initial symptoms of HIV?

Answer 12

Flu-like illness

If untreated, it can damage the immune system over time.

Question 13

How is HIV transmitted?

Answer 13

• Direct sexual contact
• Exchange of bodily fluids (e.g., sharing needles)
• From mother to child during birth or breast milk

There is no cure, but antiretroviral drugs can control the disease.

Question 14

What illness does the influenza virus cause?

Answer 14

‘Flu’

It infects airway cells, leading to high temperature, body aches, and fatigue.