B3 Communicable Disease (page 43)

Question 1

What are Pathogens?

Answer 1

they are microorganisms that enter the body and cause disease.

Question 2

What do Pathogens cause?

Answer 2

they cause communicable (infectious) diseases - diseases that can easily spread (see page 36)

Question 3

Can plants and animals be infected by pathogens?

Answer 3

yes both can.

Question 4

What is Bacteria?

Answer 4

they are very small cells (about 1/100th the size of a bacterium), which can reproduce rapidly inside your body.

Question 5

How do Bacteria make you feel ill?

Answer 5

by producing toxins (poisons) that damage your cells and tissues.

Question 6

What are Viruses?

Answer 6

Viruses are not cells. They’re tiny, about 1/100th the size of a bacterium. Like bacteria, they can reproduce rapidly inside your body.

Question 7

How do a viruse reproduce rapidly inside your body?

Answer 7

They live inside your cells and repicate themselves using the cells’ machinery to produce many copies of themselves. the cell will usually then burst, releasing all the new viruses.

This cell damage is what makes you feel ill. (see diagram on page 43).

Question 8

What are Protists?

Answer 8

they are single-celled eukaryotes.

There are lots of different types of protists. But they’re all eukaryotes (see page 11) and most of them are single-celled.

Question 9

Some Protists are parasites, what are parasites?

Answer 9

Parasites live on or inside other oranisms and can cause them damage. They often transferred to the organism by a vector, which doesn’t get the disease itself - e.g. an insect that carries the protist.

Question 10

What is Fungi?

Answer 10

Some fungi are singl-celled. Others have a body which is made up of hyphae (thread-like structures).

Question 11

What can Hyphae do?

Answer 11

they can grow and penetrate human skin and the surface of plants, causing diseases.

Question 12

What can Hyphae produce?

Answer 12

Spores, which can spread to other plants and animals.

Question 13

What are spores?

Answer 13

a reproductive cell capable of developing into a new individual withou fusion with another reproductive cell.

Question 14

How can pathogens be spread?

Answer 14

they can be spread in many ways, such as, water, air, direct contact.

Question 15

How can pathogens spread in water?

Answer 15

Some pathogen can be picked up by drinking water or bathing in dirty water.

E.g. Cholera is a bacterial infection that’s spread by drinking water contaminated with the diarrhoea of other sufferers.

Question 16

Pathogens can be carried in the air and can then be breathed in, explain how?

Answer 16

some airborne pathogens are caried in the air in droplets produced when you cough or sneeze - e.g. the influenza virus that causes flu is spread this way.

Question 17

Some Pathogens can be picked up by direct contact, explain how?

Answer 17

some pathogens can be picked up by touching contaminated surfaces, including the skin. E.g. athlete’s foot is a fungus which makes skin itch and flake off. it’s most commonly spread by touching the same things as an infected person, e.g. shower floors and towels.