Module 1 Organelles (Lesson 4) Flashcards
Who discovered the Golgi Apparatus?
Camillo Golgi in 1898
What is the main function of the Golgi Apparatus?
Modifying, sorting, and packaging proteins and lipids for transport.
What are the three main compartments of the Golgi Apparatus?
Cis-Golgi, Medial-Golgi, Trans-Golgi
What are the two networks flanking the Golgi stacks?
Cis-Golgi Network (CGN) and Trans-Golgi Network (TGN)
What type of vesicles mediate transport from the ER to the Golgi?
COPII-coated vesicles
What type of vesicles mediate retrograde transport within the Golgi?
COPI-coated vesicles
What proteins help maintain the stacked Golgi structure?
GRASPs (Golgi Reassembly and Stacking Proteins) and Golgins
What chemical disrupts microtubules and causes Golgi fragmentation?
Nocodazole
What post-translational modification occurs extensively in the Golgi?
Glycosylation
What is the key sorting signal for retrieving ER-resident proteins from the Golgi?
KDEL sequence
Why is the Golgi Apparatus considered a polarized organelle?
It has distinct functional regions—cis, medial, and trans—which process proteins sequentially.
How do Golgins contribute to Golgi organization?
They function as tethering proteins to maintain Golgi ribbon structure and facilitate vesicle docking.
What role do microtubules play in Golgi function?
They help position the Golgi near the nucleus and facilitate vesicular transport.
How does the Golgi modify glycoproteins?
Different Golgi compartments contain enzymes that sequentially add or remove sugar residues.
What happens to the Golgi during mitosis?
It temporarily fragments into mini-stacks to allow cell division and reassembles after mitosis.
Why do yeast cells have mini-Golgi stacks instead of a ribbon structure?
Yeast cells lack a centralized microtubule organizing center (MTOC) and rely on dispersed Golgi stacks.
How does retrograde transport maintain Golgi compartment identity?
It retrieves specific enzymes to maintain distinct glycosylation patterns in each compartment.
What is the Cisternal Maturation Model, and how does it explain Golgi function?
New cisternae form from ER vesicles and mature into medial and trans compartments, with resident enzymes being retrieved via retrograde transport.
How do Golgi defects contribute to Congenital Disorders of Glycosylation (CDG)?
Mutations in glycosylation enzymes impair protein modification, leading to systemic developmental and metabolic issues.
Why does KDEL-mediated retrieval of ER proteins depend on pH differences?
KDEL receptors bind proteins at the slightly acidic pH of the Golgi but release them in the neutral ER environment.
How would you experimentally confirm that a protein undergoes glycosylation in the Golgi?
Use glycosidase treatment, metabolic labeling with sugar precursors, or fluorescently tagged glycoproteins in live-cell imaging.
How would disrupting microtubules affect Golgi function?
The Golgi would fragment into mini-stacks, impairing protein sorting and trafficking.
If a protein lacks a sorting signal, how might it still get transported?
It could be randomly captured into vesicles along with actively sorted proteins.
How could you test whether a newly discovered enzyme functions in the cis-Golgi?
Tag it with a fluorescent marker and compare localization to known cis-Golgi proteins.
If a cell accumulates misfolded proteins, how might Golgi function be affected?
ER stress could overload the Golgi with defective proteins, disrupting normal processing and trafficking.
How could a researcher determine whether a protein follows the cisternal maturation model or the vesicular transport model?
Use live-cell imaging to track fluorescently labeled Golgi proteins and observe their movement over time.
What experiment could determine if the KDEL sequence is necessary for ER retrieval?
Mutate or delete the KDEL sequence and observe if the protein remains in the Golgi instead of being retrieved to the ER
If a patient has a suspected Congenital Disorder of Glycosylation (CDG), what diagnostic test could confirm it?
Analyze serum glycoproteins using mass spectrometry to detect abnormal glycosylation patterns.
