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With respect to PKU, A - VCE - SSCE Biology - Question 3 - 2002 - Paper 1
Question 3
With respect to PKU, A. the special diet for babies with the disease would also contain reduced levels of tyrosine. B. each person in a population would have one of ... show full transcript
Worked Solution & Example Answer:With respect to PKU, A - VCE - SSCE Biology - Question 3 - 2002 - Paper 1
Step 1
A. the special diet for babies with the disease would also contain reduced levels of tyrosine.
Answer
This statement is true. The diet for infants with phenylketonuria (PKU) is specifically designed to limit dietary intake of phenylalanine, an amino acid that these babies cannot metabolize, which in turn necessitates a reduction in tyrosine as well.
Step 2
B. each person in a population would have one of three possible genotypes at the PKU gene locus.
Answer
This statement is correct. At the PKU gene locus, individuals can have one of three genotypes: homozygous for the normal allele, heterozygous carrying one normal and one mutant allele, or homozygous for the mutant allele causing PKU. This genetic variability is a key aspect of inheritance patterns.
Step 3
C. a PKU individual treated from soon after birth would not be able to pass allele p onto their offspring.
Answer
This statement is false. Even if a PKU individual is treated and has controlled dietary intake, they still possess the PKU allele and can pass it on to their offspring through reproduction. Treatment does not change their genetic makeup.
Step 4
D. because the disease can be treated, one would expect the number of babies born with PKU to decline over time.
Answer
This statement is misleading. While treatment can manage PKU effectively, it does not prevent the genetic transmission of the allele that causes the disease. Therefore, unless there is a significant reduction in the allele frequency in the population, the number of babies born with PKU may not necessarily decline.