The diagrams below represent two phases of meiosis - NSC Life Sciences - Question 3 - 2020 - Paper 1
Question 3
The diagrams below represent two phases of meiosis.
Identify part A.
Identify the phase represented by diagram 1.
Describe the events that took place in the phase b... show full transcript
Worked Solution & Example Answer:The diagrams below represent two phases of meiosis - NSC Life Sciences - Question 3 - 2020 - Paper 1
Step 1
Identify part A.
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Answer
Part A is the centrioles or centrosome.
Step 2
Identify the phase represented by diagram 1.
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Answer
The phase represented by diagram 1 is Anaphase.
Step 3
Describe the events that took place in the phase before the one represented in diagram 2.
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Answer
Before Anaphase, during Metaphase, the spindle fibres contract, aligning the chromosomes along the equatorial plane of the cell. The centromeres split, allowing the chromatids to be pulled apart towards opposite poles of the cell.
Step 4
Name the process that causes the chromosomes to have a combination of genes as shown in the diagrams.
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The process is called Crossing Over.
Step 5
Give ONE reason why the process named in QUESTION 3.1.4 is vital.
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Crossing over is vital as it leads to genetic variation, which is essential for evolution and adaptation.
Step 6
If this was a human cell, how many chromosomes would be present in the cell during the phase represented in diagram 1?
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In a human cell during Anaphase, there would be 46 chromosomes or 23 pairs.
Step 7
Explain why they are structurally different.
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Structure B consists of two DNA molecules, making it a double thread due to DNA replication, whereas Structure C consists of a single thread of DNA molecule, which is unreplicated and represents the splitting of the chromosome during Anaphase 2.
