ER retrieval signal...

If you were to remove the ER retrieval signal (KDEL) from protein disulfide isomerase (PDI), which is normally a soluble resident of the ER lumen, where would you expect the modified PDI to be located?

genetic pre-exam problems

(See attached files for full problem description)

Midterm preparation

(See attached file for full problem description) I have taken the attached pre-exam (with answers) in preparation for my midterm exam. Please make corrections with proof.

Rigor mortis

1. After death, the muscles of the body become very stiff and inextensible. This phenomenon is referred to as rigor mortis, and the muscles are said to be in a state of rigor. (a) Explain the biochemical basis of rigor mortis, in terms of the interaction of actin and myosin; ie, where in the contraction cycle is the muscle arrested? (b) Would your muscles be likely to go into rigor faster if you were to die while racing to class, or while sitting in lecture? Explain.

I cell disease

1. Children with I-cell disease ("I" for "Inclusion bodies") synthesize perfectly good lysosomal enzymes, but secrete them outside the cell instead of sorting them to lysosomes. The mistake occurs because the cells lack GlcNAc-P-transferase, which is required to create the mannose-6-phosphate marker that is essential for proper delivery of hydrolytic enzymes into the lysosomes. In principle, I-cell disease could also be caused by deficiencies in two other proteins: the phosphoglycosidase that removes GlcNAc to expose mannose-6-phosphate, and the mannose 6-phosphate receptor itself. These three potential kinds of I-cell disease could be distinguished by the abi... click for more