USABO Open Exam 2005 Questions &
Answers (Grade A+)
The production of the genetically engineered "golden rice" could be
important to the people of developing nations, especially in South-
East Asia, because:
A. people are more likely to consume yellow grains than white
B. golden rice is less expensive to grow and harvest than white rice
C. golden rice is resistant to most commercially available herbicides
D. golden rice contains higher concentrations of β-carotene than
white rice
E. golden rice has been engineered to produce biodegradable
plastics -
correct answer ✅D. golden rice contains higher concentrations of
β-carotene than white rice
A large population of laboratory rats was allowed to breed
randomly for a number of generations. In this population, a
dominant allele at the A locus codes for agouti fur (A), and a
recessive allele codes for black fur (a). At the beginning of the
breeding cycles, 49% of the rats had black fur. At the end of the
breeding cycles, this percentage was the same. The rest of the
animals had agouti fur with heterozygotes indistinguishable from
homozygous dominants. What percentage of this population is
,USABO Open Exam 2005 Questions &
Answers (Grade A+)
probably heterozygous for the fur color trait assuming the rats are
following Hardy-Weinberg population genetics?
A. 7%
B. 30%
C. 42%
D. 49%
E. 70% -
correct answer ✅C. 42%
In Pompe's disease, the liver is damaged due to the accumulation
of glycogen. What organelle is most likely malfunctioning?
A. endoplasmic reticulum
B. golgi apparatus
C. lysosome
D. nucleus
E. vacuole -
correct answer ✅C. lysosome
, USABO Open Exam 2005 Questions &
Answers (Grade A+)
Transport of which nutrient across the intestinal epithelium is by
passive diffusion?
A. alanine
B. fructose
C. glucose
D. glutamine
E. all of the above -
correct answer ✅B. fructose
Which two brain centers control mammalian respiration?
A. medulla oblongata and substantia nigra
B. medulla oblongata and pons
C. medulla oblongata and red nucleus
D. substantia nigra and red nucleus
E. red nucleus and pons -
correct answer ✅B. medulla oblongata and pons
Answers (Grade A+)
The production of the genetically engineered "golden rice" could be
important to the people of developing nations, especially in South-
East Asia, because:
A. people are more likely to consume yellow grains than white
B. golden rice is less expensive to grow and harvest than white rice
C. golden rice is resistant to most commercially available herbicides
D. golden rice contains higher concentrations of β-carotene than
white rice
E. golden rice has been engineered to produce biodegradable
plastics -
correct answer ✅D. golden rice contains higher concentrations of
β-carotene than white rice
A large population of laboratory rats was allowed to breed
randomly for a number of generations. In this population, a
dominant allele at the A locus codes for agouti fur (A), and a
recessive allele codes for black fur (a). At the beginning of the
breeding cycles, 49% of the rats had black fur. At the end of the
breeding cycles, this percentage was the same. The rest of the
animals had agouti fur with heterozygotes indistinguishable from
homozygous dominants. What percentage of this population is
,USABO Open Exam 2005 Questions &
Answers (Grade A+)
probably heterozygous for the fur color trait assuming the rats are
following Hardy-Weinberg population genetics?
A. 7%
B. 30%
C. 42%
D. 49%
E. 70% -
correct answer ✅C. 42%
In Pompe's disease, the liver is damaged due to the accumulation
of glycogen. What organelle is most likely malfunctioning?
A. endoplasmic reticulum
B. golgi apparatus
C. lysosome
D. nucleus
E. vacuole -
correct answer ✅C. lysosome
, USABO Open Exam 2005 Questions &
Answers (Grade A+)
Transport of which nutrient across the intestinal epithelium is by
passive diffusion?
A. alanine
B. fructose
C. glucose
D. glutamine
E. all of the above -
correct answer ✅B. fructose
Which two brain centers control mammalian respiration?
A. medulla oblongata and substantia nigra
B. medulla oblongata and pons
C. medulla oblongata and red nucleus
D. substantia nigra and red nucleus
E. red nucleus and pons -
correct answer ✅B. medulla oblongata and pons
