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A typical antibody molecule comprises four polypeptide chains that are linked together - VCE - SSCE Biology - Question 6 - 2008 - Paper 1
Question 6
A typical antibody molecule comprises four polypeptide chains that are linked together. The following diagram shows the four fragments of a particular antibody molec... show full transcript
Worked Solution & Example Answer:A typical antibody molecule comprises four polypeptide chains that are linked together - VCE - SSCE Biology - Question 6 - 2008 - Paper 1
Step 1
i. Redraw these fragments in the box above to show the typical representation of an antibody.
Answer
To represent the typical structure of an antibody, draw a Y-shaped figure with two identical arms and a stem. Each arm should consist of a heavy chain (thicker lines) and a light chain (thinner lines) that intersect at the variable regions where antigen binding occurs. Make sure to label the variable regions at the tips of the arms.
Step 2
ii. On your answer to part i, in the box above, draw two arrows to indicate the two positions at which antigen would bind to the antibody.
Answer
Place two arrows at the tips of the Y-shaped figure you have drawn, indicating where the antigen would bind to the variable regions of the antibody.
Step 3
b. Outline the general characteristics of an autoimmune disease.
Answer
An autoimmune disease is characterized by the body's immune system mistakenly identifying its own cells as foreign. This results in the immune system attacking healthy tissues, leading to inflammation and damage. Common features include chronic inflammation, tissue damage, and a range of symptoms that may vary based on the specific autoimmune condition.
Step 4
c. Write a new definition for a hormone, covering the majority of situations in which we know hormones are involved.
Answer
A hormone is a signaling molecule synthesized in one part of the body and released into the bloodstream, where it travels to target organs to regulate physiological processes, maintaining homeostasis and coordinating various functions such as growth, metabolism, and immune responses.
Step 5
d. Design an experiment to test the scientist's prediction.
Answer
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State the hypothesis that you are testing: The hypothesis is that administering vitamin D tablets to laboratory mice will reduce the development of rheumatoid arthritis.
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Outline the experimental procedure that you follow: Select two groups of laboratory mice that normally develop rheumatoid arthritis. One group (experimental group) will receive vitamin D tablets daily for a specified period, while the other group (control group) will receive a placebo. Monitor both groups for signs of arthritis, measuring the onset and severity of symptoms through physical examinations and behavioral observations.
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Describe results that would support your hypothesis: Results supporting the hypothesis would include a significant delay in the onset of arthritis and reduced severity of symptoms in the experimental group compared to the control group, demonstrating the potential protective effects of vitamin D against the disease.