USABO Practice Test
USABO Competition Practice Test 2025-2026
Guide
1.
B C D clear
Thales is prided as the first Greek philosopher and postulated that water is the unifying principle of the universe. Which of the
following is a property of water?
A. Water is least dense at 0 C.
B. Linear hydrogen bonds involving water are stronger than covalent bonds.
C. Water has a lower heat capacity than methanol.
D. Hydroxide is the conjugate base of water.
E. Water boils at a higher temperature than blood plasma.
2.
B C D clear
Which of the following statements are FALSE regarding the secretion of hormones by the anterior pituitary? SELECT ALL
THAT APPLY.
1/25
, USABO Practice Test
3.
B C D clear
2/25
, USABO Practice Test
You inserted the coding sequence for your favorite protein into the HindIII site. You find that E. coli carrying this plasmid
express the protein in the presence of IPTG, a lactose analog. What DNA elements would you expect to find in proximity to the
HindIII site? Select the choice which gives the appropriate elements in the correct order.
1. Binding sites for the LacI repressor.
2. Enhancer sequences.
3. Poly-A sequence.
4. Ribosomal binding site.
5. Stop codon(s).
6. Strong constitutive promoter.
A. 1, 2, 4, [HindIII site], 5, 3.
B. 2, 1, 4, [HindIII site], 3, 5.
C. 6, 1, 3, [HindIII site], 4, 5.
D. 1, 6, 4, [HindIII site], 3, 5.
E. 6, 1, 4, [HindIII site], 5, 3.
4.
B C D clear
As DNA replication is occurring, the molecule below is inserted into the nascent DNA strand as it lengthens. Which statement
below is TRUE of the progress of replication immediately afterwards?
Source: Wikipedia.
A. DNA replication would halt because there is an extra 5 -phosphate group for DNA polymerase to add the next nucleotide.
B. DNA replication would halt because there is no 3 OH for DNA polymerase to add the next nucleotide.
C. DNA replication would halt because there is no 5 OH for DNA polymerase to add the next nucleotide.
D. DNA replication would continue, but the new strand would have to be built from 3 to 5 .
E. DNA replication would proceed normally.
3/25
USABO Competition Practice Test 2025-2026
Guide
1.
B C D clear
Thales is prided as the first Greek philosopher and postulated that water is the unifying principle of the universe. Which of the
following is a property of water?
A. Water is least dense at 0 C.
B. Linear hydrogen bonds involving water are stronger than covalent bonds.
C. Water has a lower heat capacity than methanol.
D. Hydroxide is the conjugate base of water.
E. Water boils at a higher temperature than blood plasma.
2.
B C D clear
Which of the following statements are FALSE regarding the secretion of hormones by the anterior pituitary? SELECT ALL
THAT APPLY.
1/25
, USABO Practice Test
3.
B C D clear
2/25
, USABO Practice Test
You inserted the coding sequence for your favorite protein into the HindIII site. You find that E. coli carrying this plasmid
express the protein in the presence of IPTG, a lactose analog. What DNA elements would you expect to find in proximity to the
HindIII site? Select the choice which gives the appropriate elements in the correct order.
1. Binding sites for the LacI repressor.
2. Enhancer sequences.
3. Poly-A sequence.
4. Ribosomal binding site.
5. Stop codon(s).
6. Strong constitutive promoter.
A. 1, 2, 4, [HindIII site], 5, 3.
B. 2, 1, 4, [HindIII site], 3, 5.
C. 6, 1, 3, [HindIII site], 4, 5.
D. 1, 6, 4, [HindIII site], 3, 5.
E. 6, 1, 4, [HindIII site], 5, 3.
4.
B C D clear
As DNA replication is occurring, the molecule below is inserted into the nascent DNA strand as it lengthens. Which statement
below is TRUE of the progress of replication immediately afterwards?
Source: Wikipedia.
A. DNA replication would halt because there is an extra 5 -phosphate group for DNA polymerase to add the next nucleotide.
B. DNA replication would halt because there is no 3 OH for DNA polymerase to add the next nucleotide.
C. DNA replication would halt because there is no 5 OH for DNA polymerase to add the next nucleotide.
D. DNA replication would continue, but the new strand would have to be built from 3 to 5 .
E. DNA replication would proceed normally.
3/25
