Question 1

What is F-actin?

Accepted Answer

The filamentous form of actin is a helical structure formed from actin monomers.It resembles a two-stranded string or cable.One end contains a "point" and the other end is "barbed."

Question 2

Energy used to propel molecular motors includes

Accepted Answer

A)  ATP. 
B)  ion gradients. 
C)  heat. 
D)  light. 
E)  ATP and ion gradients. 
A)  ATP. 
B)  ion gradients. 
C)  heat. 
D)  light. 
E)  ATP and ion gradients. E

Question 3

What is the rate and distance of the movement of myosin heads?

Accepted Answer

A)  Each head moves 5 times per second, approximately 110 Angstroms. 
B)  Each head moves 10 times per second, approximately 10 Angstroms. 
C)  Each head moves 800 times per second, approximately 10 Angstroms. 
D)  Each head moves 800 times per second, approximately 110 Angstroms. 
E)  None of the answers is correct. 
A)  Each head moves 5 times per second, approximately 110 Angstroms. 
B)  Each head moves 10 times per second, approximately 10 Angstroms. 
C)  Each head moves 800 times per second, approximately 10 Angstroms. 
D)  Each head moves 800 times per second, approximately 110 Angstroms. 
E)  None of the answers is correct. A

Question 4

Actin polymers will assemble

Accepted Answer

A)  automatically by self-assembly. 
B)  only in the presence of myosin. 
C)  with the aid of chaperone proteins. 
D)  in the presence of GTP 
E)  None of the answers is correct. 
A)  automatically by self-assembly. 
B)  only in the presence of myosin. 
C)  with the aid of chaperone proteins. 
D)  in the presence of GTP 
E)  None of the answers is correct.

Question 5

What is the cause of Charcot-Marie-Tooth disease?

Accepted Answer

This neuropathy is c

Question 6

How do molecular motors work?

Accepted Answer

Proteins undergo conformationa

Question 7

Binding of ATP causes ______________.

Accepted Answer

A)  a decrease in myosin head affinity for actin filaments 
B)  an increase in myosin head affinity for actin filaments 
C)  no change in myosin head affinity for actin filaments 
D)  cross-linking of the myosin head and actin filaments 
E)  complete abolition of affinity between actin and myosin 
A)  a decrease in myosin head affinity for actin filaments 
B)  an increase in myosin head affinity for actin filaments 
C)  no change in myosin head affinity for actin filaments 
D)  cross-linking of the myosin head and actin filaments 
E)  complete abolition of affinity between actin and myosin

Question 8

Regulated actin polymerization is central to the changes in

Accepted Answer

A)  shape of macrophages. 
B)  cell motility in amebae. 
C)  flagella movement in bacteria. 
D)  shape of macrophages and cell motility in amebae. 
E)  All the answers are correct. 
A)  shape of macrophages. 
B)  cell motility in amebae. 
C)  flagella movement in bacteria. 
D)  shape of macrophages and cell motility in amebae. 
E)  All the answers are correct.

Question 9

Binding of ATP causes ______________.

Accepted Answer

A)  a decrease in kinesin affinity for microtubules 
B)  an increase in kinesin affinity for microtubules 
C)  no change in kinesin affinity for microtubules 
D)  cross-linking of kinesin to microtubules 
E)  kinesin to completely dissociate from microtubules 
A)  a decrease in kinesin affinity for microtubules 
B)  an increase in kinesin affinity for microtubules 
C)  no change in kinesin affinity for microtubules 
D)  cross-linking of kinesin to microtubules 
E)  kinesin to completely dissociate from microtubules

Question 10

How does the action of kinesin differ from that of myosin on its track?

Accepted Answer

Myosin binds and releases acti

Question 11

Molecules that cause bacteria to swim away from toxic substances are

Accepted Answer

A)  cheomoattractants. 
B)  chemotaxis. 
C)  chemorepellants. 
D)  hormones 
E)  None of the answers is correct. 
A)  cheomoattractants. 
B)  chemotaxis. 
C)  chemorepellants. 
D)  hormones 
E)  None of the answers is correct.

Question 12

Taxol inhibits the proliferation of cells by stabilizing the polymer form of _________________.

Accepted Answer

microtubul

Question 13

What are flagella used for in bacteria?

Accepted Answer

A)  chemostasis 
B)  chemoselection 
C)  chemokinesis 
D)  chemotaxis 
E)  chemoprotection 
A)  chemostasis 
B)  chemoselection 
C)  chemokinesis 
D)  chemotaxis 
E)  chemoprotection

Question 14

The structure of dynein lends itself to the formation of

Accepted Answer

A)  monomeric proteins. 
B)  dimers. 
C)  oligomers. 
D)  dynein fibers. 
E)  None of the answers is correct. 
A)  monomeric proteins. 
B)  dimers. 
C)  oligomers. 
D)  dynein fibers. 
E)  None of the answers is correct.

Question 15

What is the "biased random walk" movement of bacteria,and when do they engage in this type of movement?

Accepted Answer

In the presence of a gradient of a chemo

Question 16

What is the functional unit of a muscle cell?

Accepted Answer

A)  myosin 
B)  actin 
C)  mitochondria 
D)  sarcomere 
E)  None of the answers is correct. 
A)  myosin 
B)  actin 
C)  mitochondria 
D)  sarcomere 
E)  None of the answers is correct.

Question 17

Troponin reacts in response to the _______________ ion.

Accepted Answer

The answer of Troponin reacts in response to the _______________...

Question 18

Bacterial motors differ from eukaryotic ones in that the bacterial motor

Accepted Answer

A)  moves along a polymeric track. 
B)  moves when ATP is hydrolyzed. 
C)  moves when GTP is hydrolyzed. 
D)  spins around a central axis. 
E)  None of the answers is correct. 
A)  moves along a polymeric track. 
B)  moves when ATP is hydrolyzed. 
C)  moves when GTP is hydrolyzed. 
D)  spins around a central axis. 
E)  None of the answers is correct.

Question 19

What part of kinesin undergoes conformational change after nucleotide binding?

Accepted Answer

A)  head domain 
B)  light chain 
C)  $\alpha$-helical lever arm 
D)  switch II 
E)  neck linker 
A)  head domain 
B)  light chain 
C)  $\alpha$-helical lever arm 
D)  switch II 
E)  neck linker

Question 20

Which of the following is a bundle of nine microtubule pairs surrounding two singlet microtubules?

Accepted Answer

A)  axoneme 
B)  dynein 
C)  Arp-actin 
D)  tropomyosin 
E)  None of the answers is correct. 
A)  axoneme 
B)  dynein 
C)  Arp-actin 
D)  tropomyosin 
E)  None of the answers is correct.

Exam 35: Molecular Motors

What is F-actin?

Energy used to propel molecular motors includes

What is the rate and distance of the movement of myosin heads?

Actin polymers will assemble

What is the cause of Charcot-Marie-Tooth disease?

How do molecular motors work?

Binding of ATP causes ______________.

Regulated actin polymerization is central to the changes in

Binding of ATP causes ______________.

How does the action of kinesin differ from that of myosin on its track?

Molecules that cause bacteria to swim away from toxic substances are

Taxol inhibits the proliferation of cells by stabilizing the polymer form of _________________.

What are flagella used for in bacteria?

The structure of dynein lends itself to the formation of

What is the "biased random walk" movement of bacteria,and when do they engage in this type of movement?

What is the functional unit of a muscle cell?

Troponin reacts in response to the _______________ ion.

Bacterial motors differ from eukaryotic ones in that the bacterial motor

What part of kinesin undergoes conformational change after nucleotide binding?

Which of the following is a bundle of nine microtubule pairs surrounding two singlet microtubules?

Biochemistry: An Evolving Science

Protein Composition and Structure

Exploring Proteins and Proteomes

DNA, RNA, and the Flow of Genetic Information

Exploring Genes and Genomes

Exploring Evolution and Bioinformatics

Hemoglobin: a Portrait of a Protein in Action

Enzymes: Basic Concepts and Kinetics

Catalytic Strategies

Regulatory Strategies

Carbohydrates

Lipids and Cell Membranes

Membrane Channels and Pumps

Signal-Transduction Pathways

Metabolism: Basic Concepts and Design

Glycolysis and Gluconeogenesis

The Citric Acid Cycle

Oxidative Phosphorylation

The Light Reactions of Photosynthesis

The Calvin Cycle and the Pentose Phosphate Pathway

Glycogen Metabolism

Fatty Acid Metabolism

Protein Turnover and Amino Acid Catabolism

The Biosynthesis of Amino Acids

Nucleotide Biosynthesis

Biosynthesis of Membrane Lipids and Steroids

The Integration of Metabolism

DNA Replication, repair, and Recombination

RNA Synthesis and Processing

Protein Synthesis

The Control of Gene Expression in Prokaryotes

The Control of Gene Expression in Eukaryotes

Sensory Systems

The Immune System

Drug Development

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