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In specialised cells in the ovary and testis, cells divide by the process of meiosis to produce gametes - VCE - SSCE Biology - Question 3 - 2003 - Paper 1
Question 3
In specialised cells in the ovary and testis, cells divide by the process of meiosis to produce gametes. A cell with a diploid number of 4 underwent meiosis. The fol... show full transcript
Worked Solution & Example Answer:In specialised cells in the ovary and testis, cells divide by the process of meiosis to produce gametes - VCE - SSCE Biology - Question 3 - 2003 - Paper 1
Step 1
Using the letters under each cell (A–F), put the cells in order commencing with the earliest stage of meiosis shown.
Answer
The correct order of the meiosis stages from earliest to latest is: C, E, D, B, F, A.
- C - This stage represents prophase I where homologous chromosomes condense and start to pair up.
- E - This depicts metaphase I where the homologous pairs align at the equatorial plate.
- D - This shows anaphase I where the homologous chromosomes are separated to opposite poles.
- B - This indicates telophase I where two nuclei form around the separated chromosomes.
- F - In this stage, prophase II occurs in which the second meiotic division begins, and the cells prepare for metaphase II.
- A - This is metaphase II where sister chromatids align along the equator before being pulled apart.
Step 2
During meiosis, crossing over and recombination occur between homologous chromosomes. Describe the outcome of recombination.
Answer
Crossing over leads to genetic variation by allowing the exchange of genetic material between homologous chromosomes. This results in new combinations of alleles on the chromosomes, increasing diversity in the gametes produced. During this process, segments of DNA are swapped, leading to offspring with different traits than those of their parents.
Step 3
Step 4
Explain how you reached your answer.
Answer
I identified cell E as anaphase I because it shows the chromosomes moving apart from each other, which is characteristic of this phase. In anaphase I, it is crucial to observe that homologous chromosomes are separated, as opposed to sister chromatids, which would be separated during anaphase II.