USABO Test prep
Which statement is true about enzymes? Enzymes...
A. Are made up of a base containing nitrogen, phosphate, and ribose.
B. Have activity that is independent of temperature and pH.
C. Lose some or all of their normal activity when their 3-D structure is disrupted.
D. Provide the activation energy needed to activate a reaction. E. Work once only and then
are destroyed. - correct answer-C. Lose some or all of their normal activity when their 3-D
structure is disrupted.
You have a multicellular organism that reproduces asexually by fission. When you excise a
~10,000 cell portion of its body, both the original organism and the excised portion grow into
fully formed, healthy organisms. You take one of the offspring and repeat the procedure for
one hundred and twenty-three generations. Each time, the resulting organisms are healthy.
What must be true of the nuclei of this species?
A. The cells contain plasmids.
B. The cells have multiple forms of DNA polymerase.
C. The cells have the majority of their genome stored in circular DNA.
D. The cells contain active telomerase.
E. The cells contain active fissonase. - correct answer-D. The cells contain active
polymerase
Which of the following correctly describes how the lifespan of a protein is regulated?
A. The part of the sequence coded for by the UTR tags it for destruction.
B. Giant protein complexes called ubiquitins destroy proteins after they have remained in the
cell for a certain time.
C. Proteins are methylated over time; heavily methylated proteins are destroyed by
proteasomes.
D. Proteins are tagged with ubiquitins, which are recognized by proteasomes; the
proteasomes destroy the proteins.
E. Proteins tagged with methyl groups are destroyed by ubiquitins. - correct answer-D.
Proteins are tagged with ubiquitins, which are recognized by proteasomes; the proteasomes
destroy the proteins.
Of the following amino acids, which is least likely to form strong interactions with other amino
acids that contribute to the tertiary structure of a given protein? A. Histidine
B. Glutamate
C. Cysteine
D. Glycine
E. Serine - correct answer-D. Glycine
Thymine dimers arise when two adjacent thymine bases become covalently linked. This
interferes with normal DNA geometry and will cause replication errors. Which of the following
agents is the primary cause of the thymine dimers?
A. Chemical mutagens
B. Beta emissions from radioactive decay
Which statement is true about enzymes? Enzymes...
A. Are made up of a base containing nitrogen, phosphate, and ribose.
B. Have activity that is independent of temperature and pH.
C. Lose some or all of their normal activity when their 3-D structure is disrupted.
D. Provide the activation energy needed to activate a reaction. E. Work once only and then
are destroyed. - correct answer-C. Lose some or all of their normal activity when their 3-D
structure is disrupted.
You have a multicellular organism that reproduces asexually by fission. When you excise a
~10,000 cell portion of its body, both the original organism and the excised portion grow into
fully formed, healthy organisms. You take one of the offspring and repeat the procedure for
one hundred and twenty-three generations. Each time, the resulting organisms are healthy.
What must be true of the nuclei of this species?
A. The cells contain plasmids.
B. The cells have multiple forms of DNA polymerase.
C. The cells have the majority of their genome stored in circular DNA.
D. The cells contain active telomerase.
E. The cells contain active fissonase. - correct answer-D. The cells contain active
polymerase
Which of the following correctly describes how the lifespan of a protein is regulated?
A. The part of the sequence coded for by the UTR tags it for destruction.
B. Giant protein complexes called ubiquitins destroy proteins after they have remained in the
cell for a certain time.
C. Proteins are methylated over time; heavily methylated proteins are destroyed by
proteasomes.
D. Proteins are tagged with ubiquitins, which are recognized by proteasomes; the
proteasomes destroy the proteins.
E. Proteins tagged with methyl groups are destroyed by ubiquitins. - correct answer-D.
Proteins are tagged with ubiquitins, which are recognized by proteasomes; the proteasomes
destroy the proteins.
Of the following amino acids, which is least likely to form strong interactions with other amino
acids that contribute to the tertiary structure of a given protein? A. Histidine
B. Glutamate
C. Cysteine
D. Glycine
E. Serine - correct answer-D. Glycine
Thymine dimers arise when two adjacent thymine bases become covalently linked. This
interferes with normal DNA geometry and will cause replication errors. Which of the following
agents is the primary cause of the thymine dimers?
A. Chemical mutagens
B. Beta emissions from radioactive decay
