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Biochemistrytest1
biochem
| Question | Answer |
|---|---|
| HbA1 | normal adult hemoglobin - a heterotetramer |
| HbS | sickle cell hemoglobin Glu replaced by Val in the B chain |
| Chaperones | helps refold newly synthesized proteins and misfolded proteins. |
| Cis-trans-prolpyl isomerases | interconvert cis and trans peptide bonds of proline residues. |
| Protein disulfide isomerases | catalyze breakage and formation of disulfide cysteine bonds |
| heat shock proteins(Hsp) | help refold proteins that heat has misfolded them(powered by ATP) |
| glycosylation | carbohydrates |
| hydroxylation | hydroxyl groups |
| phosphorylation | phosphoryl groups |
| methylation | methyl groups |
| proteolysis | cleaving protein chain |
| specific sequence glycosylated is | Asn-X-Thr/Ser |
| N-linked glycosylation occurs at | cotranslationally |
| O-linked glycosylation occurs later in the | Golgi apparatus postranslational |
| Mannose 6-phosphate determines the lysosomal destination | targeting of enzymes to lysosomes |
| insulin are produced in the | pancreatic islet cells |
| The A-chain of insulin begins with | Gly |
| The B-chain of insulin beings with | Phe |
| Procollagens contain the repeating tripeptide sequence | Gly-X-Y several hundred times. |
| Desmosine cross-link contains | three allysines and one lysine |
| PEST protieins(rich in P,E,S and T) | are also rapidly degraded. |
| Calpains involves | perform limited proteolysis |
| Caspases involves | apoptosis(programmed cell death) can activate cysteine aspartyl proteases |
| proteasome | degrades cell proteins that are marked for degradtion by ubiquitination or other means |
| lysosomes | organelle rich in hydrolytic enzymes for degrading and recycling unneeded cell components |