BIO 2B03 EXAM REVIEW | QUESTIONS AND ANSWERS |
2026 UPDATE | RATED 100% CORRECT.
is the RER dynamic or stationary? Answer - dynamic
what is the function of the RER? Answer - co-translational transport, protein
modification, formation of vesicles that will transport proteins from ER to Golgi
what is the function of the SER? Answer - fatty acid and phospholipid
synthesis, carbohydrate metabolism, regulate Ca2+ conc in the cytosol
what are the post translational modifications in the ER? Answer - -
glycosylation
- protein folding
- disulphide bond formation
- proteolytic cleavage
do modifications to proteins embedded in the ER membrane occur in the
luminal portion or the transmembrane domain or the cytosolic portion?
Answer - luminal
this protein modification is important for proteins that mediate cell interactions
with the extracellular matrix and for receptor-ligand recognition Answer -
glycosylation
,this protein modification is common on proteins that are secreted from the cell
and proteins embedded in the cell membrane Answer - glycosylation
what is the most common form of glycosylation? Answer - N-linked
N-linked glycosylation adds a polysaccharide to which group of which amino
acid? Answer - NH2 group of the R-group of asparagine
these proteins recognize modified proteins and assist in protein folding in a
similar way as chaperones Answer - lectins
what are the two types of lectins? Answer - calnexin and calreticulin
where is calnexin found? Answer - ER membrane
what is BiP? mention 3 functions Answer - - ER-resident HSP70 chaperone
- transfers proteins from ER through the translocon by binding to proteins as
soon as they appear on the luminal side of the membrane during co-
translational transport
- initiate unfolded protein response in the ER
what are the co-chaperones of BiP? Answer - Hsp40 and NEF
is cytoplasm a reducing or an oxidizing environment? Answer - reducing
is ER a reducing or an oxidizing environment? Answer - oxidizing
, does disulphide bond formation occur in reducing or oxidizing environment?
Answer - oxidizing
this protein is one of many proteins secreted into the intestine where it aids in
the digestion of RNA by cleaving it into small pieces Answer - RNAse A
what is the protein that resides in the ER that promotes oxidation? Answer -
protein disulphide isomerase (PDI)
does proteolytic cleavage in the ER happen in the lumen or the cytosol?
Answer - lumen
what is the N-terminal signal sequence of type I integral proteins cleaved by?
Answer - signal peptidase
what are the two responses of the unfolded protein response (UPR)? Answer -
1. restore normal cell function by slowing down new protein translation or
removing unfolded proteins from the ER for degradation through ubiquitylation
2. increase production of chaperones
what are the proteins essential to UPR? Answer - BiP and Ire1
this protein is involved in the UPR and functions as a chaperone to assist in
proper folding and prevent aggregation of misfolded proteins Answer - BiP
this is a transmembrane protein that is involved in the UPR Answer - Ire1
Ire1 endonuclease specifically targets which gene's mRNA? Answer - Hac1
2026 UPDATE | RATED 100% CORRECT.
is the RER dynamic or stationary? Answer - dynamic
what is the function of the RER? Answer - co-translational transport, protein
modification, formation of vesicles that will transport proteins from ER to Golgi
what is the function of the SER? Answer - fatty acid and phospholipid
synthesis, carbohydrate metabolism, regulate Ca2+ conc in the cytosol
what are the post translational modifications in the ER? Answer - -
glycosylation
- protein folding
- disulphide bond formation
- proteolytic cleavage
do modifications to proteins embedded in the ER membrane occur in the
luminal portion or the transmembrane domain or the cytosolic portion?
Answer - luminal
this protein modification is important for proteins that mediate cell interactions
with the extracellular matrix and for receptor-ligand recognition Answer -
glycosylation
,this protein modification is common on proteins that are secreted from the cell
and proteins embedded in the cell membrane Answer - glycosylation
what is the most common form of glycosylation? Answer - N-linked
N-linked glycosylation adds a polysaccharide to which group of which amino
acid? Answer - NH2 group of the R-group of asparagine
these proteins recognize modified proteins and assist in protein folding in a
similar way as chaperones Answer - lectins
what are the two types of lectins? Answer - calnexin and calreticulin
where is calnexin found? Answer - ER membrane
what is BiP? mention 3 functions Answer - - ER-resident HSP70 chaperone
- transfers proteins from ER through the translocon by binding to proteins as
soon as they appear on the luminal side of the membrane during co-
translational transport
- initiate unfolded protein response in the ER
what are the co-chaperones of BiP? Answer - Hsp40 and NEF
is cytoplasm a reducing or an oxidizing environment? Answer - reducing
is ER a reducing or an oxidizing environment? Answer - oxidizing
, does disulphide bond formation occur in reducing or oxidizing environment?
Answer - oxidizing
this protein is one of many proteins secreted into the intestine where it aids in
the digestion of RNA by cleaving it into small pieces Answer - RNAse A
what is the protein that resides in the ER that promotes oxidation? Answer -
protein disulphide isomerase (PDI)
does proteolytic cleavage in the ER happen in the lumen or the cytosol?
Answer - lumen
what is the N-terminal signal sequence of type I integral proteins cleaved by?
Answer - signal peptidase
what are the two responses of the unfolded protein response (UPR)? Answer -
1. restore normal cell function by slowing down new protein translation or
removing unfolded proteins from the ER for degradation through ubiquitylation
2. increase production of chaperones
what are the proteins essential to UPR? Answer - BiP and Ire1
this protein is involved in the UPR and functions as a chaperone to assist in
proper folding and prevent aggregation of misfolded proteins Answer - BiP
this is a transmembrane protein that is involved in the UPR Answer - Ire1
Ire1 endonuclease specifically targets which gene's mRNA? Answer - Hac1
