5 (a) Measles is a communicable disease caused by a virus - Edexcel - GCSE Biology Combined Science - Question 5 - 2020 - Paper 1
Question 5
5 (a) Measles is a communicable disease caused by a virus.
(i) What can a virus also be classified as?
A. a bacterium
B. a fungus
C. a pathogen
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Worked Solution & Example Answer:5 (a) Measles is a communicable disease caused by a virus - Edexcel - GCSE Biology Combined Science - Question 5 - 2020 - Paper 1
Step 1
What can a virus also be classified as?
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Answer
A virus can be classified as C. a pathogen. Pathogens are organisms that cause disease, which includes viruses.
Step 2
Give one reason why measles is described as a communicable disease.
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Answer
Measles is described as a communicable disease because it can spread from one person to another via respiratory droplets when an infected person coughs or sneezes.
Step 3
Which type of cell is destroyed by the HIV virus?
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Answer
The type of cell destroyed by the HIV virus is C. white blood cell. Specifically, HIV primarily infects CD4+ T cells, a type of white blood cell that plays a crucial role in the immune system.
Step 4
Describe how the specific immune system defends the body against disease.
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The specific immune system defends the body against disease through several key mechanisms:
Antigen Recognition: Pathogens contain unique structures called antigens that are recognized by lymphocytes.
Antibody Production: Upon recognizing a pathogen, B lymphocytes produce specific antibodies that bind to the antigens, neutralizing the pathogen.
Memory Cells: After an infection, some of these lymphocytes become memory cells, which allow for a faster response if the same pathogen invades again, providing immunity.
