USABO Open Exam 2005
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 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
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
The presence of a vertebral column is with respect to all vertebrates [first term], but is with
respect to all chordates [second term].
A. analogous; homologous
B. analogous; derived
C. derived; primitive
D. homologous; analogous
E. primitive; derived - correct answer-E. primitive; derived
The main explanation for the lack of a continuing abiotic origin of life on Earth today is that:
A. there are no molten surfaces on which weak solutions of organic molecules could
polymerize
B. all habitable places on earth are already filled to capacity
C. there is much less visible light reaching Earth now than when life first originated
D. there is not enough lightening to provide an energy source
E. our oxidizing atmosphere is not conducive to spontaneous formation of complex
molecules - correct answer-E. our oxidizing atmosphere is not conducive to spontaneous
formation of complex molecules
An inbred strain of plants has a mean height of 24 cm. A second strain of the same species
also has a mean height of 24 cm. When these plants are crossed, the F1 are also 24 cm.
However, when the F1 plants are crossed, the F2 plants show a wide range of heights; the
majority of F2 are like P1 and F1, but approximately 4 of 1000 are only 12 cm tall and 4 of
1000 are 36 cm tall. What fraction of the F2 plants will be 27 cm in height? [Assume that for
the genes involved in determining plant height, each allele contributes the same amount.]
A. 3/4
B. 9/16
C. 56/256
D. none
E. cannot be determined from the information given - correct answer-C. 56/256
To be functional, a linear chromosome most often contains at least:
A. two telomeres, one centromere, and a large number of origins of replication
B. one telomere, two centromeres, and a large number of origins of replication
C. two centromeres and an origin of replication
D. one centromere and an origin of replication
E. two telomeres and an origin of replication - correct answer-A. two telomeres, one
centromere, and a large number of origins of replication
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 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
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
The presence of a vertebral column is with respect to all vertebrates [first term], but is with
respect to all chordates [second term].
A. analogous; homologous
B. analogous; derived
C. derived; primitive
D. homologous; analogous
E. primitive; derived - correct answer-E. primitive; derived
The main explanation for the lack of a continuing abiotic origin of life on Earth today is that:
A. there are no molten surfaces on which weak solutions of organic molecules could
polymerize
B. all habitable places on earth are already filled to capacity
C. there is much less visible light reaching Earth now than when life first originated
D. there is not enough lightening to provide an energy source
E. our oxidizing atmosphere is not conducive to spontaneous formation of complex
molecules - correct answer-E. our oxidizing atmosphere is not conducive to spontaneous
formation of complex molecules
An inbred strain of plants has a mean height of 24 cm. A second strain of the same species
also has a mean height of 24 cm. When these plants are crossed, the F1 are also 24 cm.
However, when the F1 plants are crossed, the F2 plants show a wide range of heights; the
majority of F2 are like P1 and F1, but approximately 4 of 1000 are only 12 cm tall and 4 of
1000 are 36 cm tall. What fraction of the F2 plants will be 27 cm in height? [Assume that for
the genes involved in determining plant height, each allele contributes the same amount.]
A. 3/4
B. 9/16
C. 56/256
D. none
E. cannot be determined from the information given - correct answer-C. 56/256
To be functional, a linear chromosome most often contains at least:
A. two telomeres, one centromere, and a large number of origins of replication
B. one telomere, two centromeres, and a large number of origins of replication
C. two centromeres and an origin of replication
D. one centromere and an origin of replication
E. two telomeres and an origin of replication - correct answer-A. two telomeres, one
centromere, and a large number of origins of replication
