B5 - communicable diseases exam questions

Question 1

viruses cause disease
what name is given to microorganisms which cause infectious disease (1 mark)

Answer 1

pathogen

Question 2

how do viruses cause symptoms of disease (1 mark)

Answer 2

viruses reproduce inside cells, damaging them

Question 3

suggest one reason why viruses are not considered cells (1 mark)

Answer 3

• they do not have a cell membrane
• they do not have a cytoplasm
• they do not have a nucleus
• they do not have mitochondria
• they do not have ribosomes

Question 4

what does a vaccine contain (1 mark)

Answer 4

a weakened form of a virus

Question 5

which part of a plant shows discolouration caused by TMV (1 mark)

Answer 5

leaf

Question 6

name one type of pathogen that causes infectious disease (1 mark)

Answer 6

bacteria, fungi, protists

Question 7

which 2 defence systems prevent microorganisms infecting the human body? (2 marks)

air is warmed as it is breathed into lungs

hydrochloric acid is produced by the stomach

teeth in the mouth crush and kill microorganisms

the skin is a barrier covering the whole body

Answer 7

hydrochloric acid is produced by the stomach

the skin is a barrier covering the whole body

Question 8

how does the immune system destroy microorganisms? (1 mark)

Answer 8

white blood cells engulf the microorganisms

Question 9

complete the sentences (2 marks)

In a vaccine, the measles virus is ____________.

If the measles virus enters the body after vaccination the immune system reaction will be ________________.

Answer 9

IN THIS ORDER ONLY

weakened
fast

Question 10

how is the measles virus spread from one person to another? (1 mark)

Answer 10

by coughs and sneezes

Question 11

how do poisonous berries help a deadly nightshade plant survive (1 mark)

Answer 11

prevent animals from eating them/it will not be eaten

Question 12

what type of defence mechanism are berries on a deadly nightshade plant (1 mark)

• chemical
• mechanical
• physical

Answer 12

chemical

Question 13

what factors must a drug be tested for in trial? (3 marks)

Answer 13

toxicity, efficacy and dosage

Question 14

what type of pathogen causes malaria (1 mark)

Answer 14

a protist

Question 15

describe how the human body:

• prevents pathogens from entering the body
• defends itself against pathogens inside the body

(6 marks)

Answer 15

prevents pathogens from entering body:
- skin acts as a barrier
- scabs form a barrier over cuts
- platelets form clots/scabs
- stomach contains hydrochloric acid to kill bacteria ingested
- eyes produce tears which contain enzymes to kill bacteria
- mucus is sticky and traps bacteria

defends itself from pathogens inside the body:
- white blood cells engulf pathogens
- antibodies destroy pathogens
- antitoxins neutralise toxins
- memory cells cause a more rapid response when pathogen re-enters the body

Question 16

a man has the following symptoms:
- yellow discharge from his penis
- pain when urinating

the man has a bacterial infection. what is most likely the cause of the man’s symptoms?

why did the antibiotics not cure his symptoms?

using a condom can help stop the bacteria from being passed on to another person during sexual intercourse. name one other way the could avoid passing bacteria on

(3 marks)

Answer 16

gonorrhoea

the bacteria was resistant to the antibiotics

abstain from sexual intercourse

Question 17

two symptoms of infection by salmonella are vomiting and diarrhoea. what causes these symptoms? (1 mark)

Answer 17

bacteria release toxins which make us feel ill

Question 18

where were these drugs originally extracted from? (2 marks)

digitalis
aspirin

Answer 18

IN THIS ORDER ONLY
foxglove
willow tree

Question 19

why do some patients take a placebo (1 mark)

Answer 19

acts as a control

Question 20

explain why prescribing an antibiotic will not cure HIV (2 marks)

Answer 20

HIV is a virus and antibiotics do not kill viruses (viruses live inside of cells)