BIS104 final review

ALL T/F

To identify if a protein is in a complex with another one, the best experimental approach to use is cell fractionation.

False

In a given biological membrane, the two layers have the same composition.

False

A dependent variable is the one we perturb in an experiment to observe the consequences.

False

Before a cell fractionation protocol, a detergent can be used to lyse the cells.

False

The better the resolution of a microscope, the better its magnificaion.

True

Liposomes separation in a density gradient is possible because they are different in size.

false

A monoclonal antibody is made of antibody molecules which recognize exactly the same epitope.

true

in an SDS-PAGE proteins are charged so they move towards an electrode.

true

a membrane composed of sphingolipids with unsaturated As is more fluid than a membrane of sphingolipids with saturated FAs.

true

In an SDS-PAGE, the bigger protein will move further in the gel.

false

fluorophore-conjugated antibodies can be used in live cells to detect intracellular proteins.

false

we can use mass spec to identify different peptides in a given mixture because these peptides have different mass and charge.

true

cell lines can be maintained indefinitely in culture.

true

an epitope is the part of the antibody that specifically binds to an antigen.

false

denaturing detergents can be used to lyse cells before immunoprecipitation.

false

if enzyme A is necessary for a biochemical reaction t occur, then it means it is also sufficient for that reaction to occur.

false

a secondary antibody recognizes the variable region of a primary antibody.

false

all the subcellular compartments of a given cell have the same lipidic composition.

false

protein o-glycosylation happens in the golgi.

true

Transporters/carriers change their conformation in a sequential fashion in response to the binding of the solute they transport

true

A cytosolic protein mutated so it contains a lysosome sorting signal will be present in the lysosome instead of the cytosol

false

in the process of budding different adaptor proteins are used to ensure vesicles formed have the ran and vSNAREs required to reach a specific target compartment

true

the signal sequence is the part of the protein that informs about the final subcellular localization of a protein

false

the signal recognition particle (SRP) is a transmembrane protein in the endoplasmic reticulum

false

all proteins with a signal sequence are translocated co-translationally

true

traffic between compartments of the secretory pathway is mediated by vesicles

true

only transporters are selective for what they allow to cross the cell membrane

false

the final subcellular localization of proteins that are fully translated in the cytosol can be the plasma membrane

false

a single mutation that results in the absence of a peroxisome sorting receptor can be the cause of non-functional peroxisomes in the cell

true

proteins which have a nuclear localilization signal use exportin to go across the nuclear pore to the nucleoplasm

false

all signal sequences get cleaved off the protein following translocation

false

a protein whose final destination is the ER begins translation in the cytosol

true

guanine exchange factors (GEF) are responsible for the exchange of gtp to gdp in monomeric GTPases

false

the topology of a transmembrane protein never changes once it is synthesized 

true

transport mediated by a certain channel will happen at the same rate independently of the difference of the solute concentration between the two compartments involved

false

when talking about transport of solutes across the membrane both channels and transporters/carries can be used in the context of active transport

false

a synchronous culture exposed to a DNA stain is displayed in a FACS histogram with both high and low fluorescence regions

false

CDK has different substrate specificity depending on the cyclin is bound to 

true

centromeres duplicate during s phase

true

myosin is a motor protein that use microtubules to walk over them

false

 cells spend the whole period of interphase replicating their DNA

false

phosphorylation of cdk by CAK (Cdk activating kinase) is sufficient for cdk activation

false

regulation of translation can explain the changes in cyclin levels during the cell cycle

false

in in-vitro assembly assays, microtubules need to be studied individually in contrast with actin filaments that can be studied as a population

true

cells can only integrate 3H thymidine into their DNA while they are undergoing mitosis

false

cyclins can be ubiquitinated once phosphorylation by its corresponding cyclin/cdk complex

true

g-actin is added to and removed from the actin filaments in the atp-bound form

false

in an in-vitro actin assembly, if the concentration of free actin is lowered while the filaments are in treadmilling, the length of the filaments will not change

false

during the process of microtubules assembly diners of alpha and beta tubulin are incorporated

true

GTP-cap is a protein bound to the positive end of the microtubules that protects them from catastrophe events

false

individual actin subunits assemble one after another in the same orientation creating polar filaments structurally different at each end

true

the same cyclin-cdk pair is responsible for all phase transitions in the cell cycle

false

cyclin/cdk complexes activity is regulated by inhibitory phosphorylations that can be quickly reverted once a small amount of cdk/cyclin activity is present

true

cdc6 is present in the ORIs of replication during S phase

false