Exam 2 Short answer and multiple choice questions

The outer diameter of a microtubule is ....... nm.

25

The number of amino acids in an actin monomer is: - 375 - 450 - 460-780 - 750

375

The diameter of the actin filament is ...... nm

7

Which of the following statements is NOT true? - Intermediate filaments and actin filaments treadmill. - Intermediate filaments and microtubules have a single monomer. - Intermediate filaments and microtubules have a role at the centrosome. - Two of the above. - All of the above.

All of the Above

The preassembled carbohydrate tree is added on....... Residue.

Asparagine

At steady state equilibrium, microtubules in a test tube have a ....... and .....end.

Assembly, disassembly

What causes a myosin II molecule to be able to form a bipolar fiber? - Myosin I. - Myosin - like chain kinase. - Calcium binding to calmodulin. - Two of the above. - Three of the above

Calcium binding to calmodulin.

he 9+0 configuration refers to......, and is found only in ........cells.

Centrioles, animal

In a living cell, which end of the microtubule is effectively capped?.........

Disassembly end

An organic precipitation works because the solvent _________ disrupts the __________ of the solute.

Ethanol, hydrogen bonding or shell of hydration

True or False: A half patch signal will get a protein half way into the nucleus.

False

True or False: A hemidesmosome connects one cell to another.

False

True or False: Actin filaments will only assemble in parallel bundles.

False

True or False: Constitutive exocytosis routinely requires more signal sequences than regulative exocytosis.

False

True or False: Desmosome junctions are calcium-dependent but cadherin junctions are not.

False

True or False: In neurons, actin filaments are really intermediate filaments

False

True or False: Intermediate filaments assemble and disassemble in a living cell.

False

True or False: Intermediate filaments have no more strength than a microtubule dimer.

False

True or False: Nuclear lamins differs in all the different cell types of an organism:

False

True or False: The carbohydrate tree added to proteins targeted to the primary lysosome is added on an amino acid different from the amino acid where the carbohydrate tree is added to a transmembrane protein.

False

True or False: The dynactin complex acts only on actin filaments.

False

True or False: The inside/outside rule applies only to regulative exocytosis.

False

True or False: The nuclear lamins have no connection with the outside of the nucleus.

False

True or False: The nuclear pore complex provides a site that always lets proteins into the nucleus

False

True or False: Treadmilling of actin filaments only occurs in a test tube.

False

The electron dense cloud surrounding the centrioles in animal cells contains nucleation sites for: MTs made out of alpha and beta subunits MTs made of gamma tubulin does not exist; it is just an artifact of electron microscopy all of the above none of the above

MTs made of gamma tubulin

The molecular weight of intermediate filaments is: - 45 kDa - 42 kDa - 66 kDa - 55 kDa - None of the above

None of the Above

The number 6 carbon of mannose is exposed: - in the nucleus - in the rough endoplasmic reticulum - in the smooth endoplasmic reticulum - in the medial phase of the Golgi - None of the above

None of the above

Gamma-tubulin is present in ......

The centrosome

The intracellular preference for microtubules is .............

The centrosome

When a membrane vesicle leaves the endoplasmic reticulum, ........... assembles into ......... using ......... to produce a vesicle.

Triskelion, clathrin, ATP

During vesicular transport, which of the following are the correct sequences of events as a vesicle leaves the organelle? - Triskelion, clathrin, recycle, Rab, SNARE - Triskelion, clathrin, Rab, SNARE - SNARE, Rab, triskelion, clathrin, recycle - Triskelion, clathrin, recycle - Triskelion, clathrin, SNARE, Rab

Triskelion, clathrin, recycle, Rab, SNARE

Preassembled nucleaton sites in a living cell are equivalent to the intracellular preference for actin filaments

True

True or False: A lipase is a protein.

True

True or False: Actin filaments associate with a nucleotide triphosphate.

True

True or False: At the trans face of the Golgi, triskelion assembles into clathrin to cause removal of the putative primary lysosome.

True

True or False: BiP is a chaperone.

True

True or False: COP I can have a role in the position of protein disulfide isomers.

True

True or False: Desmin is present in muscle cells.

True

True or False: Gap junctions in plant cells cannot close.

True

True or False: Homogenization buffer can be identical to an intracellular buffer.

True

True or False: It is important to be able to repeatedly fractionate the cell.

True

True or False: Microtubules transport new membrane in the form of vesicles to the golgi apparatus from the ER.

True

True or False: One of the reasons that intermediate filaments have strength is the same reason that bipolar fibers of myosin II have strength.

True

True or False: The barrier function of an epithelium extends the role of the plasma membrane over a larger surface area.

True

Actin filaments will - undergo treadmilling in a test tube. - undergo treadmilling in a living cell. - never reach equilibrium. - two of the above.

Two of the above (A and C)

The ability of actin filaments to disassemble into small monomers: - enables the building blocks of actin filaments to move from one side of the cell to the other. - is not relevant to actin filaments. - is relevant to treadmilling. - two of the above. - None of the above

Two of the above (A and C)

The proton pump that lowers the pH below 5.5 or lower i the forming primary lysosome starts working in: - the medial face of the Golgi Apparatus - in the trans face of the Golgi Apparatus - after clathrin has been recycled. - None of the above. - All of the above.

after clathrin has been recycled.

Molecular motors working with microtubules: - are calcium-dependent ATPases - use microtubule singlets and doublets - use microtubule singlets and triplets - two of the above - none of the above

are calcium-dependent ATPases

Tight junctions: - set up a geography of the lipid layer of the cell and only let small molecules but not water pass through. - set up a geography in the proteins of the membrane and let only water but not small molecules pass through. - set up a geography of membrane proteins but adhering junctions stop the water from passing through. - are protected by the strength of adhering junctions. - are made out of only one type of protein

are protected by the strength of adhering junctions.

The binding of the signal recognition particle to the nascent peptide .................... protein synthesis.

arrests

To move cargo from one side of the cell to the other, the sequence would be in the following order: - kinesin, centrosome, plasma membrane - kinesin, centrosome, dynein - plasma membrane, centrosome, kinesin, - kinesin, nucleus, dynein - dynein, centrosome, kinesin

dynein, centrosome, kinesin

Actin filaments: - have a diameter of 7 nm and contain 375 amino acids. - are composed of 2 subunits each of molecular weight of 42 kDa. - have a diameter of 7 nm and contain 450 amino acids. - have no polarity. - have GTP in each of the monomers. - The correct answer is not listed.

have a diameter of 7 nm and contain 375 amino acids.

Hydrolysis of ATP to ADP: - helps identify the assembly vs the disassembly end - is used in dynamic instability - has a role when the actin filament is in chemical equilibrium with - - the actin filament monomers - is important for the nucleation site

helps identify the assembly vs the disassembly end

Treadmilling can occur: - only for the microtubule. - in a test tube for actin filaments and microtubules. - but is overridden by dynamic instability. - only when GTP is hydrolyzed to GDP. - when the alpha and beta subunits bind to GDP.

in a test tube for actin filaments and microtubules.

The monomer of tubulin: - has 3 subunits in it. - is a monomer with a molecular weight of 42 kDa. - is a dimer with a molecular weight of 220 kDa. - is a heterodimer with a total molecular weight of 110 kDa. - None of the above.

is a heterodimer with a total molecular weight of 110 kDa.

Intracellular preference for actin filaments : - is a way to look a the geography of the cell and the role of the nucleus. - is a way to look at the geography of the cell and show where the role of actin filaments is important. - explain how actin gets into the nucleus. - explain how the Golgi Apparatus forms. - two of the above.

is a way to look at the geography of the cell and show where the role of actin filaments is important.

Dynein is a molecular motor that: - moves cargo to the plasma membrane - moves cargo to actin filaments - moves cargo to the centrosome - acts as an actin filament - none of the above

moves cargo to the centrosome

After homogenization the first centrifugation pellets the ________ nucleus or nuclei

nucleus or nuclei

A sucrose gradient is used to purify ________ away from other ________.

plasma membrane, membrane parts or membrane component

The receptor for mannose-6-phosphate caps the proteins destined for the primary lysosome at the: - smooth endoplasmic reticulum - medial face of the Golgi - trans face of the Golgi - two of the above - in the primary lysosome

trans face of the Golgi

The function of the stop- transfer and start-transfer sequences is to make a ..................... protein.

transmembrane

The subunit of clathrin is.......

triskelion