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A student set up an experiment as shown - HSC - SSCE Biology - Question 27 - 2014 - Paper 1
Question 27
A student set up an experiment as shown. Set-up 1: Rat core body temperature sensor ------------- Data logger Computer -------------- Carbon dioxide s... show full transcript
Worked Solution & Example Answer:A student set up an experiment as shown - HSC - SSCE Biology - Question 27 - 2014 - Paper 1
Step 1
Explain why the carbon dioxide concentrations rose in each of the incubators.
Answer
The rise in carbon dioxide (CO₂) concentrations in both incubators can be attributed to cellular respiration. CO₂ is a waste product generated during this biological process, which occurs as both the rat and the snake metabolize energy from their food. As the animals respire, they release CO₂ into the incubators, leading to an increase in the overall carbon dioxide concentrations.
Step 2
Sketches both lines showing the correct starting points and the correct trends.
Answer
For the graphs representing the core body temperatures of the rat and snake against the incubator temperature:
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Rat: Starting point at 37°C when incubator temperature is 25°C. The graph shows a horizontal line remaining stable until the incubator temperature approaches around 10°C.
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Snake: Starting point at 25°C when incubator temperature is also at 25°C. The graph shows a downward trend towards 10°C, indicating a steady decline in core body temperature.
Step 3
Predict two physiological or behavioral observations in the rat.
Answer
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The rat increases its food intake due to the lowering ambient temperature, as it requires more energy to maintain its body temperature.
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The rat exhibits increased physical activity, potentially to generate heat through movement, as a response to the decrease in incubator temperature.