Organelle Logistics Cluster Worksheet
NYSSLS Life Science : Biology Cluster Item Set • HS-LS1-1, HS-LS1-2
Organelle Coordination & Protein Logistics
Name:
Date:
Period:
Phenomenon: The Cellular Assembly Line in Pancreatic Beta Cells
Stimulus 1 of 2
Pancreatic beta cells manufacture and secrete the hormone insulin to maintain glucose homeostasis. To map the pathway and timeline of protein synthesis and export, cell biologists conducted a classic pulse-chase autoradiography experiment. Cells were briefly incubated with radioactive amino acids (3H-leucine) for 3 minutes (the "pulse"), then transferred to media with non-radioactive amino acids (the "chase"). At set intervals, researchers measured the percentage of labeled protein localized within distinct organelles.
Organelle Pathway MODEL A
Nucleus (DNA → mRNA) Rough ER (Ribosomes) Golgi Apparatus Plasma Membrane Exocytosis → Insulin into Blood Mitochondria (ATP Energy)
Key: Vesicles shuttle proteins between organelles; ATP from cellular respiration powers movement.
Table 1: Autoradiography Pulse-Chase Data % of Radioactive Signal
| Chase Time | Rough ER | Golgi Body | Secretory Vesicles | Extracellular |
|---|
| 3 min | 86% | 9% | 4% | 1% |
| 20 min | 28% | 58% | 11% | 3% |
| 60 min | 8% | 21% | 59% | 12% |
| 120 min | 2% | 5% | 18% | 75% |
Values reflect radioactive leucine tracked across cellular compartments following a 3-minute pulse.
1 Based on Table 1 and Model A, which biological sequence accurately describes the movement of insulin through the beta cell over time? [1 credit]
A Nucleus → Plasma Membrane → Golgi → Rough ER
B Rough ER → Golgi Apparatus → Secretory Vesicles → Extracellular
C Secretory Vesicles → Rough ER → Mitochondria → Golgi
D Golgi Apparatus → Rough ER → Nucleus → Extracellular
2 Use specific quantitative data from Table 1 to support the claim that the Golgi apparatus receives proteins from the Rough ER and modifies them prior to packaging into secretory vesicles. [2 credits]
New York State Regents Examination in Life Science: Biology • Item Cluster Practice Page 1 of 2
Cluster Part II | Clinical Investigations: Organelle Dysfunction & Homeostasis
Student Name: _______________________
Stimulus 2: Experimental Disruption of Beta Cell Organelles
Clinical Scenarios
Researchers treated cultured pancreatic beta cells with two pharmacological agents to investigate how disrupting organelle coordination alters cellular function:
Treatment 1: Antimycin A
Inhibits the electron transport chain inside mitochondria, reducing cellular ATP synthesis by 92%. Protein synthesis in ribosomes initially proceeds, but vesicle movement stops completely.
Treatment 2: Brefeldin A
Blocks transport vesicle formation between the Rough ER and Golgi apparatus. Synthesized pro-insulin accumulates inside swollen ER cisternae with zero insulin detected outside the cell.
3 Organelle Interdependence and Cellular Energy [2 credits total]
Part A: Explain why treating beta cells with Antimycin A halts the secretion of insulin, even though the genes, ribosomes, and endoplasmic reticulum remain undamaged. [1 credit]
Part B: Identify the specific transport mechanism by which secretory vesicles fuse with the cell membrane to release insulin into the bloodstream, and state whether this process requires ATP. [1 credit]
4 Constructed Response: CER Biological Explanation [3 credits]
A patient presents with chronic hyperglycemia (elevated blood glucose) because their beta cells fail to export insulin into the bloodstream. A genetic test reveals a mutation preventing vesicles from budding off the Rough ER (similar to Brefeldin A exposure).
Construct a scientific explanation describing how this cellular defect causes organism-level disruption in glucose homeostasis.
Claim: Effect on Organism Homeostasis [1 credit] State the direct physiological consequence
Evidence: Data / Scenario Observations [1 credit] Cite cellular or experimental findings from Stimulus 1 or 2
Reasoning: Biological Mechanism [1 credit] Connect organelle structure/function to insulin processing & blood regulation
New York State Regents Examination in Life Science: Biology • Item Cluster Practice Page 2 of 2
