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Calculate how many grams of STZ should be injected into a rat with a mass of 230.45 g - AQA - A-Level Biology - Question 8 - 2022 - Paper 1
Question 8
Calculate how many grams of STZ should be injected into a rat with a mass of 230.45 g. Show your working. Give your answer in standard form.
Worked Solution & Example Answer:Calculate how many grams of STZ should be injected into a rat with a mass of 230.45 g - AQA - A-Level Biology - Question 8 - 2022 - Paper 1
Step 1
Calculate the amount of STZ for 230.45 g.
Answer
To calculate how many grams of STZ should be injected, we use the given injection dose of 35 mg/kg:
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Convert the rat's mass from grams to kilograms:
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Calculate the total amount of STZ needed:
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Convert mg to grams:
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Present the answer in standard form:
Step 2
Suggest and explain why STZ was injected per unit of body mass.
Answer
Injecting STZ per unit of body mass ensures that the dosage is proportional to the size of the animal. This is important because larger rats would require more drug to achieve the same physiological effect, whereas smaller rats would require less. Standardizing the dose per kg helps in controlling variables that might affect the study results.
Step 3
Discuss the implications of using group B rats for studying type II diabetes in humans.
Answer
Group B rats, which were fed a high-fat diet, provide a model that closely resembles the conditions leading to type II diabetes in humans. Key implications include:
- Obesity: The high-fat diet may lead to obesity, a known risk factor for diabetes.
- Insulin resistance: These rats may develop insulin resistance, similarly to how humans with type II diabetes do.
- Research validity: The results from these rats may help in understanding disease mechanisms and treatment responses, thus aiding in the development of therapies for humans.
- Limitations: However, differences in physiology between rats and humans mean that results may not directly translate, necessitating further research.