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Question 1

1.1 What are symptoms of an infectious disease are caused by?

Answer 1

Symptoms of an infectious disease are caused by damage done to cells by microorganisms or the poisons (toxins) they produce

Question 2

1.1 What is an example of a symptom?

Answer 2

Fever (raised body temperature), rashes

Question 3

1.1 How is the damage done by the microorganisms?

Answer 3

The damage is done directly to the cells by the microorganism.

Question 4

1.1 How is the damage done by the toxins that the microorganisms produce?

Answer 4

some bacteria can produce proteins that can damage the material holding cells together so that the bacteria can invade deeper

Question 5

1.2 What is an example of a microorganism?

Answer 5

Bacteria and viruses

Question 6

1.2 What is a suitable condition for microorganisms to reproduce rapidly? Why?

Answer 6

Inside the human body, in places such as the intestines, is a suitable condition as they need warm moist conditions so that chemical reactions inside the microorganisms can take place.

Question 7

1.2 How do microorganisms reproduce?

Answer 7

They make copies of themselves using energy from a source of nutrients.

Question 8

1.2 What do viruses need to reproduce

Answer 8

Viruses need other cells to reproduce

Question 9

1.3 How can we calculate the population growth of microorganisms given appropriate data?

Answer 9

After each reproduction period, there will be twice as many microorganisms than at the end of the previous reproduction period.

Question 10

1.3 What do you need to know to calculate the population growth of microorganisms ?

Answer 10

• the number of microorganisms before reproduction
• how long it takes for one to reproduce
• how long there is to reproduce for

Question 11

1.4 What are white blood cells a part of?

Answer 11

White blood cells are a part of the body’s immune system.

Question 12

1.4 What is the purpose of white blood cells?

Answer 12

They deal with infectious microorganisms that enter the body.

Question 13

1.4 What are the different types of white blood cells? How can they destroy microorganisms?

Answer 13

phagocytes

lymphocytes

Question 14

1.4 how do phagocytes work and what are they?

Answer 14

non-specific white blood cells that attack anything foreign

They detect the foreign bodies and engulf then digest them

Question 15

1.4 how do lymphocytes work and what are they?

Answer 15

specific white blood cells that attack only pathogens with correct antigen markers
They produce antibodies that can neutralise pathogens by
-binding to them to damage/destroy them directly
-coat pathogens so they are easily ingested by phagocytes
- bind to pathogens and release chemical signals attracting more phagocytes
Once the right white blood cell recognises antigens, it divides to produce more identical antibodies to fight infection.

Question 16

1.5 How do antibodies recognise microorganisms?

Answer 16

White blood cells have receptors that recognise the antigens that microorganisms carry on their surface

Question 17

1.5 What are antigens?

Answer 17

Antigens are a substance that triggers immune responses

Question 18

1.5 Why are different antibodies needed to destroy different microorganisms?

Answer 18

Different microorganisms have different antigens, and that a different antibody is therefore needed to recognise each different type of microorganism

Question 19

1.6 How does the body protect itself from that particular microorganism in the future?

Answer 19

Some white blood cells stay in the blood after the infection has been fought off. These are called memory cells. These memory cells can reproduce very quickly if the same antigen enters the body again. It can produce many antibodies to kill the microorganism before you get symptoms.

Question 20

1.6 What is it called when your body can protect itself against a certain organism due to previous exposure?

Answer 20

immunity