Chapter 12- Types Of Pathogen And Disease

Question 1

What is a disease?

Answer 1

A disease is a condition that impairs the normal functioning of an organism

Question 2

What causes disease

Answer 2

A pathogen

Question 3

Types of pathogens

Answer 3

Bacteria
Fungi
Viruses
Protoctists

Question 4

What is a communicable disease

Answer 4

A disease that can spread between organisms

Question 5

Diseases caused by bacterium

Answer 5

Tuberculosis - affects animals and humans
Bacterial meningitis- affects humans
Ring rot - affects potatoes and tomatoes

Question 6

Diseases caused by viruses

Answer 6

HIV/AIDS- affects humans
Influenza- affects animals
Tobacco mosaic virus - affects plants

Question 7

Diseases caused by fungi

Answer 7

Black Sigatoka - affects banana plants
Ringworm - affects cattle
Athletes foot- affects humans

Question 8

Diseases caused by protoctists

Answer 8

Potato/tomato late blight - affects potatoes/tomatoes
Malaria- affects animals, including humans

Question 9

How do viruses damage host tissue

Answer 9

They take over cell metabolism. Viral genetic material gets into the host cell and is inserted into the host DNA. It uses the host cell to make new viruses which burst out the cell, destroying it and spreading to other cells.

Question 10

How do protoctista damage host cells

Answer 10

They take over cells and break them open as a new generation emerge. They simply digest and use cell contents as they reproduce.

Question 11

How do fungi damage host cells

Answer 11

Fungi digest living cells and destroy them. Some fungi produce toxins which affect the host cells and cause disease

Question 12

How do bacteria damage host cells

Answer 12

Most bacteria produce toxins that poison or damage the host cells in some way. Some toxins break down cell membranes, some damage or inactivate enzymes and some interfere with genetic material so the host cell cannot divide

Question 13

What is direct transmission

Answer 13

This is when the disease is transmitted directly from one organism to another.

Question 14

How can direct transmission happen

Answer 14

Direct contact - eg skin to skin contact, kissing, sexual intercourse

Inoculation- through a break in the skin, animal bites, reusing needles

Ingestion -taking in contaminated food or drink

Question 15

What is indirect transmission

Answer 15

When a disease is transmitted from one organism to another via an intermediate . Intermediates include air, water, food or a vector

Question 16

How can indirect transmission occur

Answer 16

Fomites-inanimate objects such as bedding can transfer pathogens

Droplet infection (inhalation)- mini droplets of mucus are released when you sneeze or cough. If this air is breathed by another individual, the pathogens will spread to them.

Vectors transmits communicable diseases from one organism to another. Common vectors are mosquitoes

Question 17

Factors affecting transmission

Answer 17

Living conditions - overcrowded living conditions increase the transmission of many diseases.

Social factors -income and occupation can affect transmission of diseases. Bad healthcare and education on how diseases spread, make transmission higher

Climate can also affect spread of communicable diseases. Malaria is most common is tropical countries.