prep for midterm 2 (CELLS)

The role of the ribosome is to synthesize proteins from amino acid monomers.

true

Ribosomes are composed of a large and a small subunit, each of which is made of mRNA and protein.

false

rRNA is transcribed and spliced in the nucleolus.

true

Ribosomes found free in the cytosol and ribosomes found attached to ER membranes are structurally identical.

true

A protein hormone, which is secreted out of the cell, will be synthesized co-translationally on the ER membrane.

true

Tubulin will go through the secretory pathway.

false (cyotoplasmic protein synthesized by ER)

What binds to the ER Signal Sequence?

SRP

Proteins are initially glycosylated in which organelle?

RER

The core oligosaccharide is built on the polysaccharide dolichol phosphate, which is found in the ER membrane.

false (d.p. is a lipid)

In the final step of N-linked glycosylation, Oligosaccharide Protein Transferase moves the core oligosaccharide from dolichol phosphate to an asparagine amino acid of a newly made protein.

true

What is the signal for a proteasome to destroy a protein?

Ubiquitin

The Unfolded Protein Response may involve up-regulation of molecular chaperones.

True

A protein that resides in the Golgi membrane would be synthesized by a free ribosome.

False

An NLS is an example of a(n):

amino acid sequence

Proteins with an NLS will be directed into:

Nucleus

The ER Signal Sequence is a(n):

amino acid sequence

Proteins with an ER Signal Sequence:

will initially bind to SRP.

N-linked glycosylation occurs in the:

RER lumen

In the final step, Oligosaccharide Protein Transferase moves the core oligosaccharide off of dolichol phosphate and onto an asparagine amino acid residue of a protein.

True

mRNA that encodes for a peptide neurotransmitter exits the nucleus. That mRNA will immediately:

bind to a cytoplasmic ribosome

Clathrin is located in the:

cytoplasm

A vesicle has a phosohplipid called "PLq" in its exoplasmic leaflet. When this vesicle fuses with the plasma membrane, where will PLq be located?

in the exoplasmic leaflet

you have discovered a stain that can be used to detect glycosylated proteins. If you use this stain on Ptk2 cells, which organelle would you expect to be most instensely stained?

Golgi

Microsomes are:

small vesicles formed from cell homogenization and are representative of intact membranous organelles.

It is likely that BiP has a KDEL sequence.

True

It is likely that cytochrome C has a KDEL sequence.

FALSE

The protein NSF will hydrolyze ATP to allow the SNARE coiled-coils to unwrap once the vesicles are fused.

True

E3 ubiquitin ligases transfer ubiquitins from E1 and E2 onto a misfolded protein.

True

Post-translational protein modifications may involve N-linked glycosylation, in which a core oligosaccharide is built upon an ER membrane protein called dolichol phosphate.

False

Which of the following is NOT a eukaryote?

Archaea

The primary differences between N and O-linked glycoproteins is:

what the a.a. the sugar is linked to

which statement is true? (select all that apply)

to target lysomal enzymes, phosphates are added to a mannose on the core oligosaccharide.

lysomal enzymes function optimally in acidic conditions that are maintained by hydrogen ion pumps in the lysosomal membrane

you observe that a biomolecule contains hydrocarbon rings. this is most likely a:

steroid

Epithelial cells are attached to their ECM via:

hemidesmosomes

Where are GPCRs located?

Plasma membrane

The alpha subunit of a trimeric G protein can:

bind to a GTP

dissociate from the beta and gamma subunits

activate a target enzyme

Phospholipids:

are found in membranes

have two fatty acid tails

have a phosphate group

Where are calcium ions stored in a cell?

smooth ER