Covalent cross-linking in collagen is initiated by the formation

Covalent cross-linking in collagen is initiated by the formation of reactive aldehyde groups.  Which of the following enzymes catalyzes the formation of these aldehyde groups?
A.  lysyl oxidase
B.  lysyl hydroxylase
C.  prolyl hydroxylase
D.  procollagen peptidase
E.  none of the above


Elongation of the asparagine-N-acetyl glucosamine oligosaccharide of glycoproteins takes place within
A. mitochondria.
B. lysosomes.
C. Golgi.
D. endoplasmic reticulum
E. cytosol.


Plasma membrane proteins contain a signal sequence and
A.  a stop-transfer peptide sequence.
B.  mannose-6-phosphate.
C.  a nuclear localization signal.
D.  a docking protein sequence.
E.  a KDEL sequence.