Multiple Choice
Intercalated discs and striations are characteristic of which type of muscle tissue?
127
views
2. Cell Chemistry & Cell Components
Introduction to Eukaryotic Organelles
2:33 minutesProblem 15
Textbook Question
A pancreas cell makes proteins (enzymes) that it releases to the small intestine. Which of the following best describes the path of these proteins from synthesis to exocytosis at the pancreatic cell's plasma membrane (PM)? a. Golgi → rough ER → PM, b. smooth ER → Golgi → lysosome → PM, c. rough ER → Golgi → PM, d. nucleus → Golgi → PM.
Verified step by step guidance1
Step 1: Understand where protein synthesis occurs in the cell. Proteins, especially enzymes, are synthesized by ribosomes attached to the rough endoplasmic reticulum (rough ER), not the smooth ER or Golgi apparatus.
Step 2: Recognize the role of the rough ER. After synthesis, proteins enter the rough ER where they undergo initial folding and modifications.
Step 3: Identify the next organelle in the pathway. Proteins are then transported from the rough ER to the Golgi apparatus for further processing, sorting, and packaging.
Step 4: Determine the final destination before secretion. After processing in the Golgi, proteins are packaged into vesicles that move to the plasma membrane (PM) for exocytosis.
Step 5: Eliminate incorrect options based on organelle functions. For example, the nucleus is not directly involved in protein transport, and lysosomes are for degradation, not secretion. Therefore, the correct path is rough ER → Golgi → PM.
Verified video answer for a similar problem:This video solution was recommended by our tutors as helpful for the problem above
Video duration:
2mKey Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Protein Synthesis in the Rough Endoplasmic Reticulum (Rough ER)
Proteins destined for secretion are synthesized by ribosomes attached to the rough ER. This organelle provides a site for folding and initial modifications of these proteins before they are transported to the Golgi apparatus.
Recommended video:
06:07
Endoplasmic Reticulum
Role of the Golgi Apparatus in Protein Processing and Sorting
The Golgi apparatus modifies, sorts, and packages proteins received from the rough ER. It directs proteins to their final destinations, such as secretion outside the cell via vesicles that fuse with the plasma membrane.
Recommended video:
06:02Golgi Apparatus
Exocytosis and Protein Secretion
Exocytosis is the process by which vesicles containing proteins fuse with the plasma membrane, releasing their contents outside the cell. This is essential for pancreatic cells to secrete enzymes into the small intestine.
Recommended video:
01:33Protein Secretion
Related Videos
Related Practice