Question
In which cellular components are lysosomal enzymes typically present?
| A. |
Cytosol
|
| B. |
Mitochondria
|
| C. |
Endoplasmic reticulum
|
| D. |
Nucleus
|
Show Answer
|
Correct Answer � C
Explanation
|
|
C. Endoplasmic reticulum
- Lysosomal enzymes are synthesized in the rough endoplasmic reticulum (RER).
- They are then transported to the Golgi apparatus for further modification and sorting.
- Mannose-6-phosphate (M6P) tags are added in the Golgi to direct these enzymes to lysosomes.
Pathway Summary:
- Synthesis: Lysosomal enzymes are synthesized in the RER.
- Modification: They are glycosylated and tagged with M6P in the Golgi apparatus.
- Transport: M6P receptors in the Golgi direct them to lysosomes.
Reasons for ruling out other options are-
- A. Cytosol:
- Enzymes are synthesized in the cytosol but do not stay there; they are transported to ER.
- B. Mitochondria:
- Mitochondria contain their own specific enzymes for the Krebs cycle and oxidative phosphorylation, not lysosomal enzymes.
- D. Nucleus:
- The nucleus is involved in DNA and RNA synthesis and regulation, not lysosomal enzyme storage or synthesis.
