1 Figure 1 shows a cell from an onion root tip - Edexcel - GCSE Biology Combined Science - Question 1 - 2021 - Paper 1
Question 1
1 Figure 1 shows a cell from an onion root tip. This cell is dividing by mitosis.
a) (i) Which structure is labelled Z?
A allele
B chromosome
C spindle
D nuclear ... show full transcript
Worked Solution & Example Answer:1 Figure 1 shows a cell from an onion root tip - Edexcel - GCSE Biology Combined Science - Question 1 - 2021 - Paper 1
Step 1
(i) Which structure is labelled Z?
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Answer
The structure labelled Z is identified as the chromosome. In the context of mitosis, chromosomes become visible during the prophase stage, and they are the structures that contain genetic material.
Step 2
(ii) Mitosis produces new cells. Give two reasons why mitosis is important in living things.
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Answer
Mitosis is crucial for several reasons:
Growth and Development: Mitosis allows for the growth of organisms by increasing the number of cells, which is essential for the development of tissues and organs.
Repair and Regeneration: It enables tissue repair and regeneration by producing new cells to replace damaged or dead cells.
Step 3
(iii) Draw one straight line from each stage of the cell cycle to its description.
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Answer
Here are the correct pairings for the cell cycle stages:
Interphase → DNA is copied
Prophase → A spindle is formed
Metaphase → The nuclear membrane breaks down
Cytokinesis → The cell divides in two
Step 4
(b)(i) State what can be added to the slide to make the plant cells more visible.
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Answer
To enhance the visibility of plant cells on a microscope slide, a stain or dye can be applied. This helps in highlighting the different cellular components.
Step 5
(b)(ii) Which is the total magnification of this microscope?
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Answer
To determine the total magnification, multiply the magnification of the eyepiece by the magnification of the objective lens:
Total Magnification = 10 (eyepiece) × 40 (objective) = 400.
