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From the photograph it is reasonable to conclude that A - VCE - SSCE Biology - Question 1 - 2003 - Paper 1
Question 1
From the photograph it is reasonable to conclude that A. the fetus is a female. B. there are 44 autosomes. C. the DNA sequence is identical along each of the pairs o... show full transcript
Worked Solution & Example Answer:From the photograph it is reasonable to conclude that A - VCE - SSCE Biology - Question 1 - 2003 - Paper 1
Step 1
A. the fetus is a female.
Answer
To determine if the fetus is female, we must examine the sex chromosomes in the karyotype. A female genotype is represented as XX, which can be verified by observing two X chromosomes in the figure. As both the X chromosomes are present, we can indeed conclude that the fetus is female.
Step 2
B. there are 44 autosomes.
Answer
In human karyotypes, individuals typically have 46 chromosomes in total: 22 pairs of autosomes plus 1 pair of sex chromosomes. Therefore, there are 44 autosomes, confirming that this conclusion is valid. The observed karyotype should display the typical count matching these autosomal pairs.
Step 3
C. the DNA sequence is identical along each of the pairs of chromosomes labelled 13.
Answer
Chromosomes in homologous pairs share the same genes at corresponding loci, thus the DNA sequence along chromosomes labelled 13 is identical in both chromosomes of the pair. This suggests that they contain the same genetic information which is a characteristic of homologous chromosomes.
Step 4
D. the centromeres of the chromosomes in Group A are near the ends of the chromosomes.
Answer
To evaluate this statement, we refer to the position of centromeres in Group A chromosomes. In a karyotype, metacentric chromosomes have centromeres positioned near the middle, while acrocentric chromosomes have their centromeres closer to one end. If Group A consists of acrocentric chromosomes, we may conclude that their centromeres are indeed near the ends.