Question 1

Which of the following does NOT affect microtubule polymerization and is NOT used in cancer chemotherapy?

Accepted Answer

A) taxol 
B) colchicine 
C) vinblastine 
D) vincristine 
A) taxol 
B) colchicine 
C) vinblastine 
D) vincristine

Question 2

Myofibrils are the basic structural unit in the contraction of striated muscle.What is the linear array of cylindrical structures they made of?

Accepted Answer

A) t-tubules 
B) sarcomeres 
C) sarcolemmas 
D) sarcoplasmic reticulum (SR) 
A) t-tubules 
B) sarcomeres 
C) sarcolemmas 
D) sarcoplasmic reticulum (SR)

Question 3

How does intracellular movement of organelles in axons occur?

Accepted Answer

A) through axoneme motion through ATP-driven walking of dyneins along microtubules 
B) through formation of ring-like structures around tubulin to move organelles 
C) through progressive movement along DNA strands 
D) through kinesin-mediated ATPase-driven movement along microtubules 
A) through axoneme motion through ATP-driven walking of dyneins along microtubules 
B) through formation of ring-like structures around tubulin to move organelles 
C) through progressive movement along DNA strands 
D) through kinesin-mediated ATPase-driven movement along microtubules

Question 4

Which of the following does NOT occur during kinesin movement along a microtubule?

Accepted Answer

A) Leading head binds a new site on tubulin,with ADP dissociation. 
B) The kinesin head with ADP is bound to tubulin,and the kinesin head with ATP is ready to move ahead. 
C) Conformational changes in the neck linkers flip the trailing head to the next tubulin binding site. 
D) ADP and Pi dissociate and ATP binds leading head. 
A) Leading head binds a new site on tubulin,with ADP dissociation. 
B) The kinesin head with ADP is bound to tubulin,and the kinesin head with ATP is ready to move ahead. 
C) Conformational changes in the neck linkers flip the trailing head to the next tubulin binding site. 
D) ADP and Pi dissociate and ATP binds leading head.

Question 5

Which of the following is NOT correct regarding ciliary motion?

Accepted Answer

A) ATP-driven sliding or walking of dyneins occurs along microtubules. 
B) Axonemes are surrounded by plasma membrane that is continuous with the plasma membrane of the cell. 
C) Dynein molecules bridge between microtubules,alternating their "walking" along both bridging microtubules. 
D) The result is a bending motion of the axoneme and subsequent bending of the cilia. 
A) ATP-driven sliding or walking of dyneins occurs along microtubules. 
B) Axonemes are surrounded by plasma membrane that is continuous with the plasma membrane of the cell. 
C) Dynein molecules bridge between microtubules,alternating their "walking" along both bridging microtubules. 
D) The result is a bending motion of the axoneme and subsequent bending of the cilia.

Question 6

When would inhibition occur if the non-hydrolyzable ATP analog β,γ-methylene-ATP were given to muscle cells?

Accepted Answer

A) during formation of the cross-bridge between actin and myosin 
B) during the release of ADP and Pi 
C) during the ATP binding step where actin and myosin dissociate 
D) during the conformational change in the myosin head 
A) during formation of the cross-bridge between actin and myosin 
B) during the release of ADP and Pi 
C) during the ATP binding step where actin and myosin dissociate 
D) during the conformational change in the myosin head

Question 7

Which best defines negative cooperativity of Rep helicase from E.coli?

Accepted Answer

A) When 1 subunit binds DNA,the other releases from the DNA. 
B) When both subunits are bound to DNA,ATP hydrolysis promotes release of both subunits. 
C) ATP hydrolysis promotes DNA binding of both subunits simultaneously. 
D) Once it binds ssDNA,binding dsDNA is prohibited. 
A) When 1 subunit binds DNA,the other releases from the DNA. 
B) When both subunits are bound to DNA,ATP hydrolysis promotes release of both subunits. 
C) ATP hydrolysis promotes DNA binding of both subunits simultaneously. 
D) Once it binds ssDNA,binding dsDNA is prohibited.

Question 8

How does self-assembly of microtubules occur?

Accepted Answer

A) by helical twisting of strands of α-tubulin and β-tubulin 
B) by intermolecular interactions of dimers of α-tubulin and β-tubulin 
C) by polymerization of alternating α- and β-tubulin into a repeating α-β-α-β-.strand 
D) by inter-subunit interaction to form α2β2-tetramers of tubulin 
A) by helical twisting of strands of α-tubulin and β-tubulin 
B) by intermolecular interactions of dimers of α-tubulin and β-tubulin 
C) by polymerization of alternating α- and β-tubulin into a repeating α-β-α-β-.strand 
D) by inter-subunit interaction to form α2β2-tetramers of tubulin

Exam 15: Molecular Motors

Which of the following does NOT affect microtubule polymerization and is NOT used in cancer chemotherapy?

Myofibrils are the basic structural unit in the contraction of striated muscle.What is the linear array of cylindrical structures they made of?

How does intracellular movement of organelles in axons occur?

Which of the following does NOT occur during kinesin movement along a microtubule?

Which of the following is NOT correct regarding ciliary motion?

When would inhibition occur if the non-hydrolyzable ATP analog β,γ-methylene-ATP were given to muscle cells?

Which best defines negative cooperativity of Rep helicase from E.coli?

How does self-assembly of microtubules occur?

The Facts of Life: Chemistry Is the Logic of Biological Phenomena

Water: the Medium of Life

Thermodynamics of Biological Systems

Amino Acids

Proteins: Their Primary Structure and Biological Functions

Proteins: Secondary, tertiary, and Quaternary Structure

Carbohydrates and the Glycoconjugates of Cell Surfaces

Lipids

Lipid Biosynthesis

Membranes and Membrane Transport

The Reception and Transmission of Extracellular Information

Enzymes Kinetics and Specificity

Mechanisms of Enzyme Action

Enzyme Regulation

Nutrition and the Organization of Metabolism

Glycolysis

The Tricarboxylic Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Gluconeogenesis, glycogen Metabolism, and the Pentose Phosphate Pathway

Fatty Acid Catabolism

Nitrogen Acquisition and Amino Acid Metabolism

Nucleotides and Nucleic Acids

Structure of Nucleic Acids

Synthesis and Degradation of Nucleotides

Recombinant Dna: Cloning and Creation of Chimeric Genes

DNA Metabolism: Replication, recombination, and Repair

Transcription and the Regulation of Gene Expression

Protein Synthesis

Post-Transcriptional Regulation of Gene Expression

Completing the Protein Life Cycle: Folding, processing, and Degradation

Metabolic Integration and Organ Specialization

Filters