GRE Subject Test: Biochemistry, Cell, and Molecular Biology : Endoplasmic Reticulum and Golgi Apparatus
Study concepts, example questions & explanations for GRE Subject Test: Biochemistry, Cell, and Molecular Biology
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Example Questions
Example Question #31 : Cell Biology
Which component of the Golgi apparatus is primarily responsible for "receiving" proteins to be packaged and modified?
Trans Golgi
Cisternae
Cis Golgi
Medial Golgi
Vacuoles
Cis Golgi
The cis Golgi is usually closely apposed to the endoplasmic reticulum, where proteins are synthesized by ribosomes. Once they have left the ribosome, the proteins are already close to the Golgi and are taken up by the cis side of the apparatus. The trans Golgi sends the newly packaged proteins out to their final destinations.
Example Question #32 : Cell Biology
Which component/suborganelle structure of the Golgi apparatus accepts vesicles from the rough endoplasmic reticulum containing nascent proteins to be processed through the Golgi apparatus?
Trans Golgi stack
Trans face
Lumen
Cis face
Medial Golgi stack
Cis face
The cis face of the Golgi apparatus is the first part of the apparatus that faces the rough endoplasmic reticulum and interacts with recently synthesized proteins that need to be processed and packaged by the Golgi apparatus. The rest of the structures listed are indeed parts of the Golgi that the proteins must pass through during the course of processing, but the cis face is met first.
Example Question #1 : Help With Endoplasmic Reticulum Function
Which of the following is a function of the smooth endoplasmic reticulum?
Macromolecule digestion
Triglyceride production
Protein synthesis
Ribosome production
Triglyceride production
The smooth endoplasmic reticulum lacks ribosomes on its surface, meaning it does not participate in protein translation. It does play a key role in the production of various lipids, such as phospholipids and triglycerides.
Example Question #33 : Cell Biology
Where in the cell does new membrane synthesis take place?
In the Golgi apparatus
In the ribosomes
In the endoplasmic reticulum
In the mitochondria
In the lysosome
In the endoplasmic reticulum
The endoplasmic reticulum (ER) is the cellular organelle responsible for membrane synthesis. Products from the ER are moved to the Golgi, where they are tagged and shipped off to their final destination. Lysosomes are important for degradation and ribosomes play a role in translation. Mitochondria are for energy production in the form of ATP.
Example Question #1 : Endoplasmic Reticulum And Golgi Apparatus
Which of the following organelles has the function of storing intracellular calcium?
Lysosome
Autophagosome
Golgi complex
Nucleolus
Endoplasmic reticulum
Endoplasmic reticulum
The endoplasmic reticulum, while crucial to protein synthesis, is also an intracellular calcium storage organelle, and calcium can be released in response to signaling cascades as needed. None of the other organelles listed participates in storage of calcium.
Example Question #2 : Endoplasmic Reticulum And Golgi Apparatus
What is the primary function of the Golgi apparatus?
Post-translational modifications of proteins
Protein sorting
All of these are primary functions of the Golgi apparatus
Maintaining the secretory pathway
All of these are primary functions of the Golgi apparatus
The Golgi apparatus is a complex organelle with many various functions. These functions are primarily dedicated to protein modification, protein packaging, and protein sorting. Some of post-translational modifications that take place in this organelle include glycosylation and phosphorylation. The Golgi apparatus is an important relay in the secretory pathway, as it produces the vesicles that contain most secreted peptides.
Example Question #3 : Endoplasmic Reticulum And Golgi Apparatus
Which of the following GTP-binding proteins is associated with COPI during vesicle assembly and budding in the cis-Golgi?
Glycosidases
ATPases
ADP ribosylation factors (ARFs)
SAR1A
Soluble NSF attachment protein receptor (SNARE)
ADP ribosylation factors (ARFs)
The correct answer is ADP ribosylation factors (ARFs). ARFs are active when bound by GTP, and inactive when bound by GDP. The active GTP-bound form of ARF binds the vesicle coat protein 1 (COPI), to faciliate vesicle budding from the cis-Golgi face.
Example Question #4 : Endoplasmic Reticulum And Golgi Apparatus
Each of the following functions are associated with the Golgi apparatus, except __________.
Delivery of proteins to the lysosome
Post-translational modifications to proteins to aid in their sorting
Formation of proteoglycans for the extracellular matrix
Delivery of proteins to the plasma membrane
Contains resident proteins required for the electron transport chain (ETC)
Contains resident proteins required for the electron transport chain (ETC)
The Golgi apparatus is considered the post office of the cell; proteins are received, sorted, modified, and sent to their final cellular destination. The proteins required for the electron transport chain are localized to the mitochondria, and are not within the Golgi apparatus, thus this is the correct selection.
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