First-line defences that mammals have against invasion by disease-causing bacteria include
A - VCE - SSCE Biology - Question 13 - 2008 - Paper 1
Question 13
First-line defences that mammals have against invasion by disease-causing bacteria include
A. lysozymes.
B. interferons.
C. antibodies.
D. killer T cells.
Worked Solution & Example Answer:First-line defences that mammals have against invasion by disease-causing bacteria include
A - VCE - SSCE Biology - Question 13 - 2008 - Paper 1
Step 1
A. lysozymes.
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Answer
Lysozymes are enzymes that break down the cell walls of bacteria, effectively leading to their destruction. They are part of the innate immune system and are found in various body fluids such as tears and saliva, providing a first line of defense against bacterial invasion.
Step 2
B. interferons.
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Answer
Interferons are signaling proteins released by host cells in response to viruses and some bacteria. While they are critical in the immune response, they are not classified as first-line defenses. Their primary function is to help modulate the immune response and induce antiviral state in neighboring cells.
Step 3
C. antibodies.
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Antibodies are proteins produced by B cells in response to antigens. While they play a vital role in the adaptive immune response to pathogens, they do not function as a first-line defense.
Step 4
D. killer T cells.
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Answer
Killer T cells (cytotoxic T lymphocytes) are crucial for targeting and destroying infected cells, particularly those infected by viruses. However, they are part of the adaptive immune response and not considered a first-line defense against pathogenic bacteria.
