Question 1

Which of the following is the best description of how actin and myosin work in cooperation to allow muscle contraction?

Accepted Answer

A) myosin head groups push against actin filaments to lengthen the sarcomere 
B) myosin head groups walk along the actin filament to shorten the sarcomere 
C) myosin head groups interact with actin only when the sarcomere is fully lengthened 
D) all myosin head groups move along the actin filament simultaneously to shorten the sarcomere 
E) none of the above 
A) myosin head groups push against actin filaments to lengthen the sarcomere 
B) myosin head groups walk along the actin filament to shorten the sarcomere 
C) myosin head groups interact with actin only when the sarcomere is fully lengthened 
D) all myosin head groups move along the actin filament simultaneously to shorten the sarcomere 
E) none of the above B

Question 2

Which of the following correctly describes the difference between red and white muscle?

Accepted Answer

A) red muscle has considerably more mitochondria than white muscle 
B) white muscle has a lower concentration of myoglobin than red muscle 
C) white muscle receives much less blood flow than red muscle 
D) the main source of energy in red muscle is fatty acid oxidation while in white muscle it is glycolysis 
E) all of the above 
A) red muscle has considerably more mitochondria than white muscle 
B) white muscle has a lower concentration of myoglobin than red muscle 
C) white muscle receives much less blood flow than red muscle 
D) the main source of energy in red muscle is fatty acid oxidation while in white muscle it is glycolysis 
E) all of the above E

Question 3

Which protein of the thin filament is responsible for calcium binding?

Accepted Answer

A) tropomyosin 
B) troponin C 
C) troponin T 
D) calmodulin 
E) actin 
A) tropomyosin 
B) troponin C 
C) troponin T 
D) calmodulin 
E) actin B

Question 4

What type of secondary structure is most prominent in myosin?

Accepted Answer

A) antiparallel $\beta$-sheet 
B) parallel $\beta$-sheet 
C) $\alpha$-helix 
D) 310 helix 
E) polyproline helix 
A) antiparallel $\beta$-sheet 
B) parallel $\beta$-sheet 
C) $\alpha$-helix 
D) 310 helix 
E) polyproline helix

Question 5

Which portion of the myosin protein found in muscle is responsible for both ATP and actin binding?

Accepted Answer

A) heavy-chain coiled-coiled tails 
B) heavy-chain stalk 
C) heavy-chain globular head 
D) essential light chain 
E) regulatory light chain 
A) heavy-chain coiled-coiled tails 
B) heavy-chain stalk 
C) heavy-chain globular head 
D) essential light chain 
E) regulatory light chain

Question 6

What is the 9 + 2 array seen in the axoneme?

Accepted Answer

A) 2 central microtubules ringed by 9 microtubule doublets 
B) 2 central microtubule doublets ringed by 9 microtubules 
C) 9 central microtubules with 2 microtubules attached to each central microtubule 
D) 9 central microtubules with 2 microtubule doublets attached to each central microtubule 
E) none of the above 
A) 2 central microtubules ringed by 9 microtubule doublets 
B) 2 central microtubule doublets ringed by 9 microtubules 
C) 9 central microtubules with 2 microtubules attached to each central microtubule 
D) 9 central microtubules with 2 microtubule doublets attached to each central microtubule 
E) none of the above

Question 7

Which form of myosin is found in striated muscle?

Accepted Answer

A) I 
B) II 
C) IV 
D) VI 
E) all of the above 
A) I 
B) II 
C) IV 
D) VI 
E) all of the above

Question 8

In muscle, thin filaments are made of _______ while thick filaments are made of _______.

Accepted Answer

A) myosin; actin 
B) actin; myosin 
C) myofibril; myofiber 
D) myofiber; myofibril 
E) none of the above 
A) myosin; actin 
B) actin; myosin 
C) myofibril; myofiber 
D) myofiber; myofibril 
E) none of the above

Question 9

Under typical conditions within a muscle cell, the $\Delta$G for hydrolysis of ATP is about -51 kJ/mol. If the energy required to move through one power stroke is 1.2 * 10-20 J, what is the percent utilization of the energy from ATP hydrolysis?

Accepted Answer

51 kJ/mol (1 mol / 6.02 * 10²³ m

Question 10

Which of the following correctly describes the organization that gives rise to muscle?

Accepted Answer

A) myofibril $\rarr$ sarcomere $\rarr$ myofiber $\rarr$ muscle 
B) sarcomere $\rarr$ myofiber $\rarr$ myofibril $\rarr$ muscle 
C) myofibril $\rarr$ myofiber $\rarr$ sarcomere $\rarr$ muscle 
D) sarcomere $\rarr$ myofibril $\rarr$ myofiber $\rarr$ muscle 
E) myofiber $\rarr$ myofibril $\rarr$ sarcomere $\rarr$ muscle 
A) myofibril $\rarr$ sarcomere $\rarr$ myofiber $\rarr$ muscle 
B) sarcomere $\rarr$ myofiber $\rarr$ myofibril $\rarr$ muscle 
C) myofibril $\rarr$ myofiber $\rarr$ sarcomere $\rarr$ muscle 
D) sarcomere $\rarr$ myofibril $\rarr$ myofiber $\rarr$ muscle 
E) myofiber $\rarr$ myofibril $\rarr$ sarcomere $\rarr$ muscle

Question 11

Which of the following motor proteins is correctly paired with its primary function?

Accepted Answer

A) myosin V: muscle contraction 
B) myosin II: cargo transport 
C) cytoplasmic dynein: bending of cilia or flagella 
D) axonemal dynein: cargo transport 
E) none of the above 
A) myosin V: muscle contraction 
B) myosin II: cargo transport 
C) cytoplasmic dynein: bending of cilia or flagella 
D) axonemal dynein: cargo transport 
E) none of the above

Question 12

Which of the following proteins is found in a bacterial flagellum?

Accepted Answer

A) actin 
B) myosin 
C) flagellin 
D) dynein 
E) all of the above 
A) actin 
B) myosin 
C) flagellin 
D) dynein 
E) all of the above

Question 13

Which of the following motor proteins is correctly paired with both its binding target and its direction of movement?

Accepted Answer

A) myosin II: actin filament, moves towards (-)end 
B) myosin V: actin filament, moves towards (+)end 
C) kinesin: actin filament, moves towards (+)end 
D) cytoplasmic dynein: microtubule, moves towards (+)end 
E) axonemal dynein: microtubule, can move in either direction 
A) myosin II: actin filament, moves towards (-)end 
B) myosin V: actin filament, moves towards (+)end 
C) kinesin: actin filament, moves towards (+)end 
D) cytoplasmic dynein: microtubule, moves towards (+)end 
E) axonemal dynein: microtubule, can move in either direction

Question 14

Which of the following only occurs when ATP (not ADP)is bound to the myosin head?

Accepted Answer

A) actin is released from its binding site on myosin 
B) weak binding of myosin head to actin 
C) strong binding of myosin head to actin 
D) power stroke of muscle contraction 
E) none of the above 
A) actin is released from its binding site on myosin 
B) weak binding of myosin head to actin 
C) strong binding of myosin head to actin 
D) power stroke of muscle contraction 
E) none of the above

Question 15

In a typical cell, the use of proton gradient to power ATP synthesis requires about 3 protons for each ATP. Based on this, what is the energy expenditure, in ATP/minute, of a typical flagellum if it is running at 120 revolutions per second and requires 1000 protons to make one revolution?

Accepted Answer

The answer of In a typical cell, the use of...

Question 16

Which of the following correctly describes the involvement of myosin V and kinesin in intracellular transport?

Accepted Answer

A) during transport along microtubules, both myosin V and kinesin form nonspecific interactions with tubulin 
B) during transport along microfilaments, both myosin V and kinesin form highly specific interactions with actin 
C) myosin V only joins with kinesin at the end of microtubules while kinesin dissociates from the myosin V-cargo complex at the start of microfilaments 
D) while myosin V can aid kinesin during microtubule transport, kinesin will often disrupt myosin V during transport along microfilaments 
E) none of the above 
A) during transport along microtubules, both myosin V and kinesin form nonspecific interactions with tubulin 
B) during transport along microfilaments, both myosin V and kinesin form highly specific interactions with actin 
C) myosin V only joins with kinesin at the end of microtubules while kinesin dissociates from the myosin V-cargo complex at the start of microfilaments 
D) while myosin V can aid kinesin during microtubule transport, kinesin will often disrupt myosin V during transport along microfilaments 
E) none of the above

Question 17

Microtubules are made from which of the following proteins?

Accepted Answer

A) actin 
B) myosin 
C) tubulin 
D) cytoplasmic dynein 
E) kinesin 
A) actin 
B) myosin 
C) tubulin 
D) cytoplasmic dynein 
E) kinesin

Question 18

Which of the following is the energy source for flagellum?

Accepted Answer

A) ATP hydrolysis 
B) GTP hydrolysis 
C) proton gradient 
D) sodium ion gradient 
E) none of the above 
A) ATP hydrolysis 
B) GTP hydrolysis 
C) proton gradient 
D) sodium ion gradient 
E) none of the above

Question 19

If a bacteria were found with a protein similar to flagellin but with a left-handed helical structure, how would the bacteria move when all flagella were rotating in a clockwise fashion?

Accepted Answer

A) the bacteria would tumble and change direction 
B) the bacteria would run in a straight line 
C) the bacteria would turn in a clockwise direction 
D) the bacteria would turn in a counterclockwise direction 
E) none of the above 
A) the bacteria would tumble and change direction 
B) the bacteria would run in a straight line 
C) the bacteria would turn in a clockwise direction 
D) the bacteria would turn in a counterclockwise direction 
E) none of the above

Exam 8: Contractile Proteins and Molecular Motors

Which of the following is the best description of how actin and myosin work in cooperation to allow muscle contraction?

Which of the following correctly describes the difference between red and white muscle?

Which protein of the thin filament is responsible for calcium binding?

What type of secondary structure is most prominent in myosin?

Which portion of the myosin protein found in muscle is responsible for both ATP and actin binding?

What is the 9 + 2 array seen in the axoneme?

Which form of myosin is found in striated muscle?

In muscle, thin filaments are made of _______ while thick filaments are made of _______.

Under typical conditions within a muscle cell, the Δ\DeltaΔ G for hydrolysis of ATP is about -51 kJ/mol. If the energy required to move through one power stroke is 1.2 * 10-20 J, what is the percent utilization of the energy from ATP hydrolysis?

Which of the following correctly describes the organization that gives rise to muscle?

Which of the following motor proteins is correctly paired with its primary function?

Which of the following proteins is found in a bacterial flagellum?

Which of the following motor proteins is correctly paired with both its binding target and its direction of movement?

Which of the following only occurs when ATP (not ADP)is bound to the myosin head?

In a typical cell, the use of proton gradient to power ATP synthesis requires about 3 protons for each ATP. Based on this, what is the energy expenditure, in ATP/minute, of a typical flagellum if it is running at 120 revolutions per second and requires 1000 protons to make one revolution?

Which of the following correctly describes the involvement of myosin V and kinesin in intracellular transport?

Microtubules are made from which of the following proteins?

Which of the following is the energy source for flagellum?

If a bacteria were found with a protein similar to flagellin but with a left-handed helical structure, how would the bacteria move when all flagella were rotating in a clockwise fashion?

The Scope of Biochemistry

The Matrix of Life: Weak Interactions in an Aqueous Environment

The Energetics of Life

Nucleic Acids

Introduction to Proteins: the Primary Level of Protein Structure

The Three-Dimensional Structure of Proteins

Protein Function and Evolution

Carbohydrates: Sugars, Saccharides, Glycans

Lipids, Membranes and Cellular Transport

Enzymes: Biological Catalysts

Chemical Logic of Metabolism

Carbohydrate Metabolism: Glycolysis, Gluconeogenesis, Glycogen Metabolism, and the Pentose Phosphate Pathway

Citric Acid Cycle and Glyoxylate Cycle

Electron Transport, Oxidative Phosphorylation, and Oxygen Metabolism

Photosynthesis

Lipid Metabolism I: Fatty Acids, Triacylglycerols, and Lipoproteins

Interorgan and Intracellular Coordination of Energy Metabolism in Vertebrates

Lipid Metabolism Ii: Membrane Lipids, Steroids, Isoprenoids, and Eicosanoids

Metabolism of Nitrogenous Compounds I: Principles of Biosynthesis, Utilization, and Turnover

Metabolism of Nitogenous Compounds II: Amino Acids, Porphyrins, and Neurotransmitters

Nucleotide Metabolism

Mechanisms of Signal Transduction

Genes, Genomes and Chromosomes

DNA Replication

DNA Restructuring: Repair, Recombination, Rearrangement, Amplification

Information Readout: Transcription and Post-Transcriptional Processing

Information Decoding: Translation and Post-Translational Protein Processing

Regulation of Gene Expression

Filters

In muscle, thin filaments are made of _ while thick filaments are made of _.

Under typical conditions within a muscle cell, the $\Delta$ G for hydrolysis of ATP is about -51 kJ/mol. If the energy required to move through one power stroke is 1.2 * 10^-20 J, what is the percent utilization of the energy from ATP hydrolysis?