All AP Biology Resources
Example Questions
Example Question #1 : Understanding Cytoplasmic Proteins
In which cellular compartment does glycolysis take place?
Mitochondrial matrix
Golgi apparatus
Inner mitochondrial membrane
Intermembrane space
Cytoplasm (Cytosol)
Cytoplasm (Cytosol)
Glycolysis (the process of breaking down glucose) takes place in the cytoplasm, or cytosol—the aqueous portion of the cytoplasm. It is in the cytoplasm where the enzymes required for glycolysis are found.
The citric acid cycle takes place in the mitochondrial matrix, and the electron transport chain takes place along the inner mitochondrial membrane in order to pump protons into the intermembrane space.
Example Question #2 : Understanding Cytoplasmic Proteins
What is the function of a kinase?
Remove phosphates from ligands
Add ubiquitin to the ligand
Change the structure of the ligand
Add phosphates to ligands
Add phosphates to ligands
The addition and removal of phosphate groups can serve critical functions in the regulation of protein activity. The binding or uncoupling of phosphate groups frequently serves to activate or deactivate proteins.
A kinase is an enzyme that phosphorylates—or adds a phosphate group to—its ligand.
A phosphatase removes a phosphate group from its ligand.
Several different types of proteins can change the structure of a ligand, such as isomerases, and ubiquitin ligases add ubiquitin to their ligands.
Example Question #3 : Understanding Cytoplasmic Proteins
What is the function of a phosphatase?
Change the structure of its ligand
Add an ubiquitin to its ligand
Add a phosphate to its ligand
Remove a phosphate from its ligand
Remove a phosphate from its ligand
The addition and removal of phosphate groups can serve critical functions in the regulation of protein activity. The binding or uncoupling of phosphate groups frequently serves to activate or deactivate proteins.
A phosphatase removes a phosphate group from its ligand.
A kinase is an enzyme that phosphorylates—or adds a phosphate group to—its ligand.
Several different types of proteins can change the structure of a ligand, such as isomerases, and ubiquitin ligases add ubiquitin to their ligands.
Example Question #221 : High School Biology
What is the function of an ubiquitin ligase?
Add a phosphate to its ligand
Remove an ubiquitin from its ligand
Add an ubiquitin to its ligand
Remove a phosphate from its ligand
Add an ubiquitin to its ligand
Ubiquitin ligases add ubiquitin to their ligands. The addition of ubiquitin acts as a signal that a protein has become ineffective and is ready for degradation. When multiple ubiquitin residues have been added to a protein molecule, it is transported to the lysosome in the cell to be digested.
A phosphatase removes a phosphate group from its ligand.
A kinase is an enzyme that phosphorylates—or adds a phosphate group to—its ligand.
The addition and removal of phosphate groups can serve critical functions in the regulation of protein activity. The binding or uncoupling of phosphate groups frequently serves to activate or deactivate proteins.
Several different types of proteins can change the structure of a ligand, such as isomerases.
Example Question #661 : Cellular Biology
Immediately following synthesis, where are secretory proteins moved to?
Vesicles
Golgi body
Endoplasmic reticulum
The cytosol
The membrane
Endoplasmic reticulum
When secretory proteins are synthesized they localize to the endoplasmic reticulum (ER), specifically the rough ER, for modification. Following modification there, secretory proteins are then packaged in secretory vesicles which go on to interact with the Golgi body, and are then finally released from the the plasma membrane.
Example Question #2 : Identify How Molecules Move Into And Out Of Cells
Which of the following most accurately describes how a local cell signal is transmitted among nearby eukaryotic cells in animals?
Secretion of signaling molecules into the bloodstream
A pilus
Direct contact
Unspecified diffusion of signal proteins
Direct contact
Local cell signaling in eukaryotic cells refers to the communication between nearby cells. This is done through direct contact between cells, namely via cell junctions and cell-cell recognition. Gap junctions are intercellular connections that allow cytoplasmic transfer in animal cells. The counterpart in plant cells is the plasmodesmata, which are channels penetrating the cell walls of cells, allowing communication. Cell-cell recognition is the ligand-receptor binding between two cells that elicits receptor cell response. Methods of local cell signaling allow nearby cells to communicate with each other and coordinate cellular responses and activities.
Example Question #181 : Cell Structures
Which of the following choices most likely flows into the cell through open ion-gated receptors?
Ions
The ligand that activated the channel
Genetic material
Large multi-subunit proteins
Ions
As the name implies, when activated and induced to undergo a conformational change by a ligand, ions are able to flow through the channel and into the cell. This allows the charge across the membrane tobe manipulated by the cell.
Example Question #3 : Identify How Molecules Move Into And Out Of Cells
Which of the following choices causes an ion-gated channel to deactivate and close?
Ligand dissociation
Dissociation of ion channel kinases
Change in the membrane potential
Secondary messengers
Ligand dissociation
The binding of ligands causes the activation and conformational change in the ion channel to open it. Then, ions are able to flow into the cell. After a short time, the ligand dissociates from the ion gated channel. This causes the channel to deactivate and close.
Example Question #4 : Identify How Molecules Move Into And Out Of Cells
Which of the following choices is not an an example of phagocytosis in multicellular organisms?
Uptake of hormones
Endocytosis of solid nutrient particles into cells
Uptake of foreign material
Uptake of dead cell material
Uptake of hormones
Phagocytosis is a form of endocytosis in which a cell takes up solid material through the invagination of the plasma membrane to form intracellular vesicles. In multicellular organisms, the process of phagocytosis is utilized in nutrient uptake, immune system response, and in cell recycling. Cells perform phagocytosis to uptake solid nutrients into the cell. The immune system uses phagocytosis to consume foreign material for eventual degradation. In the continual process of cell recycling, old and dead cell material is taken up and reused by cells.
Example Question #2 : Identify How Molecules Move Into And Out Of Cells
In clathrin-mediated endocytosis, why does the rate of particle uptake decline quickly?
Lack of free ligands
Negative feedback
Binding of inhibitors
Internalization of receptors
Internalization of receptors
In clathrin-mediated endocytosis, the binding of a specific ligand to a receptor triggers intracellular protein recruitment, which includes clathrin. These proteins stabilize the invagination and allow the clathrin pit to pull away from the plasma membrane. After it has separated from the membrane, the proteins and clathrin dissociate from the vesicle, which then fuses with an endosome. The invagination and vesicle formation from the plasma membrane includes the internalization of both the receptor and ligand. Over time the uptake by clathrin-mediated endocytosis decreases as the number of receptors on the cell’s surface. In other words, particle uptake declines due to the internalization of recptors as a result of clathrin-mediated endocytosis.
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