USABO Open Exam 2025/2026 Exam
Questions with Detailed Verified
Answers (100% Correct Answers) |
Already Graded A+
Both amino acids and nucleotides form complex chains. Select all the
answers below that are accurate.
A. The chains formed by both have polar phosphate groups.
B. Both contain peptide bonds.
C. Both contain nitrogen.
D. The chains formed by both can be lysed by trypsin.
E. The sequence of chains both form from preexisting templates. - 🧠
ANSWER ✔✔C. Both contain nitrogen.
E. The sequence of chains both form from preexisting templates.
When a population is in Hardy-Weinberg equilibrium, which of the following
is true?
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,A. All of its recessive lethal genes are wiped out, leaving only healthy
dominant genes.
B. dN/dt = 0, N = population size.
C. Mutations occur at five times the normal rate to balance the loss of
genes by way of natural selection.
D. The frequencies of the alleles in the population change over time.
E. The frequencies of genotypes in the population are stable over time. - 🧠
ANSWER ✔✔E. The frequencies of genotypes in the population are stable
over time.
Which of the following is NOT an accurate description of protein synthesis
and folding?
A. All protein synthesis is initiated in the cytoplasm.
B. Many copies of a protein can be synthesized simultaneously from the
same mRNA.
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,C. The 3D shape of a protein is determined largely by its amino acid
sequence.
D. The entire chain of amino acids exits the ribosome before it begins
folding into its 3D shape.
E. The first encoded amino acid in every protein is methionine. - 🧠
ANSWER ✔✔C. The 3D shape of a protein is determined largely by its
amino acid sequence.
Neurotransmitter released at the synapse binds to two classes of receptors.
Select the correct response(s).
A. Metabotropic receptors that do not form an ion pore are linked with
signal transduction mechanisms and can alter neuron function for seconds
to minutes.
B. Receptor tyrosine kinases that activate signal transduction mechanisms
and change gene transcription that can last for hours to days.
C. Ionotropic receptors that do not form an ion pore are linked with signal
transduction mechanisms and can alter neuron function for seconds to
minutes.
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, D. Ionotropic receptors that are directly linked to an ion pore and are
opened within milliseconds in response to neurotransmitter.
E. Steroid hormone receptors that can activate changes in gene
transcription that can last for hours to days. - 🧠 ANSWER ✔✔A.
Metabotropic receptors that do not form an ion pore are linked with signal
transduction mechanisms and can alter neuron function for seconds to
minutes.
D. Ionotropic receptors that are directly linked to an ion pore and are
opened within milliseconds in response to neurotransmitter.
Many proteins are transported around cells in vesicles. Which of the
following determines the specificity or directionality of vesicle transport?
A. Clathrin coat proteins.
B. v-SNARES and t-SNARES.
C. Flippase.
D. Myristoylation.
E. Hydrophobic domains. - 🧠 ANSWER ✔✔B. v-SNARES and t-SNARES.
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Questions with Detailed Verified
Answers (100% Correct Answers) |
Already Graded A+
Both amino acids and nucleotides form complex chains. Select all the
answers below that are accurate.
A. The chains formed by both have polar phosphate groups.
B. Both contain peptide bonds.
C. Both contain nitrogen.
D. The chains formed by both can be lysed by trypsin.
E. The sequence of chains both form from preexisting templates. - 🧠
ANSWER ✔✔C. Both contain nitrogen.
E. The sequence of chains both form from preexisting templates.
When a population is in Hardy-Weinberg equilibrium, which of the following
is true?
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PRIVACY STATEMENT. ALL RIGHTS RESERVED
,A. All of its recessive lethal genes are wiped out, leaving only healthy
dominant genes.
B. dN/dt = 0, N = population size.
C. Mutations occur at five times the normal rate to balance the loss of
genes by way of natural selection.
D. The frequencies of the alleles in the population change over time.
E. The frequencies of genotypes in the population are stable over time. - 🧠
ANSWER ✔✔E. The frequencies of genotypes in the population are stable
over time.
Which of the following is NOT an accurate description of protein synthesis
and folding?
A. All protein synthesis is initiated in the cytoplasm.
B. Many copies of a protein can be synthesized simultaneously from the
same mRNA.
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PRIVACY STATEMENT. ALL RIGHTS RESERVED
,C. The 3D shape of a protein is determined largely by its amino acid
sequence.
D. The entire chain of amino acids exits the ribosome before it begins
folding into its 3D shape.
E. The first encoded amino acid in every protein is methionine. - 🧠
ANSWER ✔✔C. The 3D shape of a protein is determined largely by its
amino acid sequence.
Neurotransmitter released at the synapse binds to two classes of receptors.
Select the correct response(s).
A. Metabotropic receptors that do not form an ion pore are linked with
signal transduction mechanisms and can alter neuron function for seconds
to minutes.
B. Receptor tyrosine kinases that activate signal transduction mechanisms
and change gene transcription that can last for hours to days.
C. Ionotropic receptors that do not form an ion pore are linked with signal
transduction mechanisms and can alter neuron function for seconds to
minutes.
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, D. Ionotropic receptors that are directly linked to an ion pore and are
opened within milliseconds in response to neurotransmitter.
E. Steroid hormone receptors that can activate changes in gene
transcription that can last for hours to days. - 🧠 ANSWER ✔✔A.
Metabotropic receptors that do not form an ion pore are linked with signal
transduction mechanisms and can alter neuron function for seconds to
minutes.
D. Ionotropic receptors that are directly linked to an ion pore and are
opened within milliseconds in response to neurotransmitter.
Many proteins are transported around cells in vesicles. Which of the
following determines the specificity or directionality of vesicle transport?
A. Clathrin coat proteins.
B. v-SNARES and t-SNARES.
C. Flippase.
D. Myristoylation.
E. Hydrophobic domains. - 🧠 ANSWER ✔✔B. v-SNARES and t-SNARES.
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