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The diagrams below show a pair of homologous chromosomes during cell division - VCE - SSCE Biology - Question 6 - 2015 - Paper 1
Question 6
The diagrams below show a pair of homologous chromosomes during cell division. Figure 1 shows the whole chromosomes and Figure 2 is an enlarged view of the section... show full transcript
Worked Solution & Example Answer:The diagrams below show a pair of homologous chromosomes during cell division - VCE - SSCE Biology - Question 6 - 2015 - Paper 1
Step 1
Name the type of cell division that would be occurring for this arrangement of chromosomes to be observed.
Answer
The type of cell division that would be occurring for this arrangement of chromosomes to be observed is Meiosis. This process is specifically responsible for the formation of gametes (sperm and eggs) in sexually reproducing organisms. During meiosis, homologous chromosomes are paired and can undergo processes such as crossing over, which increases genetic variation.
Step 2
Describe the process that leads to genetic variation in meiosis.
Answer
During meiosis, genetic variation is introduced primarily through two mechanisms: crossing over and independent assortment.
- Crossing Over: This occurs during prophase I of meiosis when homologous chromosomes pair up and exchange segments of genetic material. This recombination leads to new allele combinations on each chromosome.
- Independent Assortment: During metaphase I, the alignment of homologous chromosome pairs is random. This randomness means that the distribution of maternal and paternal chromosomes to daughter cells is varied, resulting in different combinations of genes in the gametes.
Step 3
Explain the significance of genetic variation.
Answer
Genetic variation is crucial for a population's ability to adapt to changing environments and is a key factor in natural selection. Higher genetic diversity within a species can increase resilience to diseases and environmental changes, ultimately enhancing survival and reproduction rates.