Photo AI
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 o... 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 accurate. Phenylketonuria (PKU) is an inherited disorder that results in the inability to metabolize the amino acid phenylalanine. A special diet for babies diagnosed with PKU typically involves reduced levels of phenylalanine and must also manage tyrosine levels since tyrosine is essential for certain bodily functions and can be impacted due to restrictions on protein intake.
Step 2
B. each person in a population would have one of three possible genotypes at the PKU gene locus.
Answer
This is a correct assertion. Individuals at the PKU gene locus can have one of three genotypes: homozygous dominant (PP), heterozygous (Pp), or homozygous recessive (pp). The presence of the recessive allele (p) determines if an individual is affected by PKU, while the combination of alleles influences the expression of the phenotype.
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 misleading. Even if a PKU individual is treated to manage their condition, they still carry the genetic allele responsible for PKU (p). Consequently, they can pass this allele on to their offspring, potentially resulting in children who are also affected by PKU if the other parent carries the recessive allele.
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 has merit. As treatment for PKU becomes more accessible and effective, and awareness increases, it can lead to a decrease in the birthrate of babies affected by PKU. This is due to informed family planning and dietary management, which can mitigate the risk of producing offspring with the disorder.