B5 - Communicable Disease

Question 1

Define pathogen.

Answer 1

microorgs. that causes disease

Question 2

What is the structure of a bacterial cell?

Answer 2

single celled, no nucleus

Question 3

How do bacteria cause disease?

Answer 3

produc. toxins

Question 4

What is the structure of a virus?

Answer 4

length of DNA surround. by a protein coat

Question 5

How do viruses cause disease?

Answer 5

invading cells, replicate & burst cells

Question 6

What is the structure of fungi?

Answer 6

eukaryotic

Question 7

How do fungi cause disease?

Answer 7

invade tissues

Question 8

By what 3 ways is tobacco mosaic virus (TMV) spread?

Answer 8

• direct contact of plants with infected plant material
• soil
• animal & plant vectors

Question 9

What are the symptoms of TMV?

Answer 9

• mosaic pattern of discolouration on leaves
• stunted growth

Question 10

Why does TMV cause stunted growth?

Answer 10

infects chloroplasts & reduces plant’s ability -> photosythesise

Question 11

What pathogen is the cause of rose black spot?

Answer 11

fungi

Question 12

How is rose black spot spread?

Answer 12

H2O & wind

Question 13

What are the symptoms of rose black spot?

Answer 13

• purple or black spots on leaves (often turn yellow & fall off)
• stunted growth

Question 14

Why does rose black spot cause stunted growth?

Answer 14

reduces rate of photosythesis & then reduces rate of growth