MBG 1000 (U of Guelph Midterm) | Questions with 100%
Verified Answers | Latest Update
Question:
What is an autosomal recessive disease?
Answer:
a disease that is recessive (meaning that both parents must be at least carriers of it to have a child
who is affected by it) and does not occur in a sex chromosome
Question:
What are symptoms of PKU?
Answer:
mental/motor imparement (tremors and jerky hand/leg movement), hyperactivity/stunted growth,
pale complexion and hair, sweat/breath/urine with musty odor
Question:
Why do the symptoms of PKU exist?
Answer:
the phenylalanine does not turn into phenylalanine hydroxylase which goes into tyrosine which
contributes to melanin and dopamine. so the excess phenylalanine collects in the blood/tissue and
turns into phenylpyruvic acid and phenylacetic acid
Question:
Why do regions in ireland/west scotland and descendents from there have more cases of PKU
Answer:
the wet climate in these areas combined with famines caused food that had gone mouldy to be
eaten. mouldy food contains ochratoxin a. ochratoxin a can cause kidney disease in adults, but
even when given in nonlethal/harmless doses to a pregnant mother, it may severely impact or kill
the baby. HOWEVER raising the blood concentration of phenylalanine, like what happens in PKU,
reduces the toxicity of ochratoxin a, causing children with a mother who has PKU to survive that
layer of natural selection.
Question:
how likely is an child of two carrier parents of an autosomal recessive disease to be affected by that
disease
Answer:
1/4 chance
Question:
how likely is an unaffected child of two carrier parents of an autosomal recessive disease to be a
carrier/not carrier
Verified Answers | Latest Update
Question:
What is an autosomal recessive disease?
Answer:
a disease that is recessive (meaning that both parents must be at least carriers of it to have a child
who is affected by it) and does not occur in a sex chromosome
Question:
What are symptoms of PKU?
Answer:
mental/motor imparement (tremors and jerky hand/leg movement), hyperactivity/stunted growth,
pale complexion and hair, sweat/breath/urine with musty odor
Question:
Why do the symptoms of PKU exist?
Answer:
the phenylalanine does not turn into phenylalanine hydroxylase which goes into tyrosine which
contributes to melanin and dopamine. so the excess phenylalanine collects in the blood/tissue and
turns into phenylpyruvic acid and phenylacetic acid
Question:
Why do regions in ireland/west scotland and descendents from there have more cases of PKU
Answer:
the wet climate in these areas combined with famines caused food that had gone mouldy to be
eaten. mouldy food contains ochratoxin a. ochratoxin a can cause kidney disease in adults, but
even when given in nonlethal/harmless doses to a pregnant mother, it may severely impact or kill
the baby. HOWEVER raising the blood concentration of phenylalanine, like what happens in PKU,
reduces the toxicity of ochratoxin a, causing children with a mother who has PKU to survive that
layer of natural selection.
Question:
how likely is an child of two carrier parents of an autosomal recessive disease to be affected by that
disease
Answer:
1/4 chance
Question:
how likely is an unaffected child of two carrier parents of an autosomal recessive disease to be a
carrier/not carrier
