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USABO OPEN TEST FINAL EXAM AND PRACTICE
EXAM QUESTIONS 2025/ 2026 ACTUAL EXAM
COMPLETE EXAM QUESTIONS WITH DETAILED
CORRECT ANSWERS /ALREADY GRADED A+ //
NEWEST EXAM!!!!
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 - Answer-D. golden rice contains
higher concentrations of β-carotene than white rice
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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 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% - 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
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B. golgi apparatus
C. lysosome
D. nucleus
E. vacuole - Answer-C. lysosome
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 - 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
USABO OPEN TEST FINAL EXAM AND PRACTICE
EXAM QUESTIONS 2025/ 2026 ACTUAL EXAM
COMPLETE EXAM QUESTIONS WITH DETAILED
CORRECT ANSWERS /ALREADY GRADED A+ //
NEWEST EXAM!!!!
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 - Answer-D. golden rice contains
higher concentrations of β-carotene than white rice
,2|Page
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 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% - 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
, 3|Page
B. golgi apparatus
C. lysosome
D. nucleus
E. vacuole - Answer-C. lysosome
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 - 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
