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
D a protist
(i... show full transcript
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 a pathogen. This classification is based on its ability to infect host organisms and cause disease.
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 be easily transmitted from one person to another, typically through 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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The HIV virus primarily destroys white blood cells, specifically the CD4 T lymphocytes. This reduction in immune cells significantly weakens the body's ability to fight infections.
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 a series of mechanisms:
Antigen Recognition: Pathogens have unique proteins called antigens on their surfaces. When these are recognized by specific immune cells, an immune response is triggered.
Antibody Production: Lymphocytes, particularly B cells, respond by producing antibodies that bind to the pathogens. This binding neutralizes the pathogens and marks them for destruction by other immune cells.
Memory Formation: After the initial response, memory cells are created that remain in the body. These cells enable a quicker and more effective response if the same pathogen infects the body again in the future.
