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 | cell R
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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.
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Answer
Cell Q is in the metaphase stage, while cell R is in the anaphase stage.
Step 2
Describe two processes that occur in cells during prophase.
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Answer
The chromatin condenses into distinct chromosomes, making them visible under a microscope.
The nuclear envelope breaks down, allowing spindle fibers to interact with the chromosomes.
Step 3
State the term used to describe the process which occurs after mitosis, when the cell divides into two.
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Answer
The process is called cytokinesis.
Step 4
Which is this diameter in µm?
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Answer
The diameter of 0.075 mm is equivalent to 75 µm.
Step 5
Describe how to adjust the microscope to view the slide at a magnification of x400.
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Answer
First, ensure the slide is properly placed on the stage. Start with the lowest magnification lens to locate the specimen, then switch to the x400 objective lens. Adjust the focus using the fine adjustment knob to get a clear view of the specimen.
Step 6
Discuss the benefits and risks of using stem cell therapy to treat arthritis.
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Benefits
Stem cells can differentiate into specialized cells that are needed for joint repair.
They can replace damaged cells in the joints and potentially restore functions.
Stem cell therapy may help reduce symptoms of arthritis, improving quality of life.
Risks
New cells might not function correctly after therapy, leading to complications.
There is a possibility that stem cells could continue to divide uncontrollably, which may result in cancer.
Some patients might experience side effects or an immune reaction, resulting in worsened conditions.
