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Figure 3 shows the banding pattern of a single sarcomere - AQA - A-Level Biology - Question 4 - 2020 - Paper 2
Question 4
Figure 3 shows the banding pattern of a single sarcomere. Creatinine is produced in muscle tissues. Creatinine diffuses into the blood. The kidneys then excrete cre... show full transcript
Worked Solution & Example Answer:Figure 3 shows the banding pattern of a single sarcomere - AQA - A-Level Biology - Question 4 - 2020 - Paper 2
Step 1
Explain the banding pattern shown in Figure 3.
Answer
The banding pattern of a sarcomere is characterized by distinct regions:
- Light band: This band contains only actin filaments, giving it a lighter appearance.
- H zone: This area contains only myosin filaments, which is slightly darker than the light band.
- Darkest overlapping region: This part consists of overlapping actin and myosin filaments, resulting in the darkest band due to the presence of both types of filaments.
Step 2
Use the information provided to describe how you could produce a calibration curve for creatinine.
Answer
To produce a calibration curve for creatinine:
- Use distilled water and creatinine solution: Prepare a series of dilutions using a known creatinine solution mixed with distilled water to make various concentrations.
- Addition of detecting solution: To each of these solutions, add the creatinine-detecting solution, which will react to produce a color change.
- Measure absorbance: Use a colorimeter to measure the absorbance of each diluted solution at a specific wavelength, documenting the absorbance values.
- Plot the calibration curve: Plot the absorbance against the corresponding concentration of creatinine, creating a calibration curve for further analysis.
Step 3
Describe how you would determine the concentration of creatinine in a urine sample using your calibration curve.
Answer
To determine the concentration of creatinine in a urine sample using the calibration curve:
- Measure the absorbance of the urine sample: Add the creatinine-detecting solution to the urine sample and measure its absorbance using the colorimeter.
- Compare to the calibration curve: Refer to the calibration curve to find the corresponding concentration of creatinine based on the measured absorbance value.