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Figure 1 shows a cell from an onion root tip - Edexcel - GCSE Biology Combined Science - Question 1 - 2021 - Paper 1
Question 1
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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
Which structure is labelled Z?
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Answer
The structure labelled Z is C spindle. The spindle is crucial during mitosis as it helps in the separation of chromosomes.
Step 2
Give two reasons why mitosis is important in living things.
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Answer
Mitosis is important for growth and tissue repair in multicellular organisms. Additionally, it allows for asexual reproduction in some organisms, helping in population increase without genetic variation.
Step 3
Draw one straight line from each stage of the cell cycle to its description.
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Answer
Interphase → DNA is copied;
Prophase (not listed but relevant) → a spindle is formed;
Metaphase (not listed but relevant) → the cell divides in two;
Cytokinesis → the nuclear membrane breaks down.
Step 4
State what can be added to the slide to make the plant cells more visible.
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Answer
To make the plant cells more visible, a stain (like iodine) can be added to the slide.
Step 5
Which is the total magnification of this microscope?
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Answer
The total magnification of the microscope is D x400, calculated as follows: magnification of eyepiece (x10) multiplied by the magnification of the objective lens (x40).
Step 6
Name one part of a light microscope that can be moved to obtain a clear image of plant cells.
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Answer
The objective lens is one part of a light microscope that can be moved to obtain a clear image of plant cells.
