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Figure 4 shows cells from an onion root tip as seen using a light microscope - Edexcel - GCSE Biology Combined Science - Question 3 - 2021 - Paper 1
Question 3
Figure 4 shows cells from an onion root tip as seen using a light microscope. (i) Identify the stages of mitosis shown in cell Q and cell R. | | cell Q ... show full transcript
Worked Solution & Example Answer:Figure 4 shows cells from an onion root tip as seen using a light microscope - Edexcel - GCSE Biology Combined Science - Question 3 - 2021 - Paper 1
Step 1
Identify the stages of mitosis shown in cell Q and cell R.
Answer
In cell Q, the stage of mitosis is metaphase (option A) where the chromosomes align at the cell's equatorial plane. In cell R, the stage is anaphase (option A) where sister chromatids are pulled apart towards opposite poles of the cell.
Step 2
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Step 5
Describe how to adjust the microscope to view the slide at a magnification of x400.
Answer
To view the slide at x400 magnification, start with the lowest power objective lens and focus on the slide using the coarse adjustment knob. Once focused, switch to the x400 objective lens and fine-tune the focus using the fine adjustment knob.
Step 6
Discuss the benefits and risks of using stem cell therapy to treat arthritis.
Answer
Benefits:
- Stem cells can differentiate into specialized cells, potentially regenerating damaged tissues in joints.
- They can replace damaged cells, improving joint function.
- Stem cell therapy may reduce symptoms of arthritis, increasing the quality of life.
Risks:
- New cells may not function correctly, leading to ineffective treatment.
- Stem cells have the potential to continue dividing uncontrollably, which may lead to tumor formation.
- There may be side effects such as immune rejection or worsening symptoms.