High School Biology : Understanding Cytoplasmic Proteins
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Example Questions
Example Question #1 : Understanding Cytoplasmic Proteins
In which cellular compartment does glycolysis take place?
Inner mitochondrial membrane
Cytoplasm (Cytosol)
Mitochondrial matrix
Golgi apparatus
Intermembrane space
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?
Add phosphates to ligands
Remove phosphates from ligands
Change the structure of the ligand
Add ubiquitin to the ligand
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?
Add a phosphate to its ligand
Add an ubiquitin to its ligand
Change the structure of 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 #4 : Identify How Molecules Move Into And Out Of Cells
What is the function of an ubiquitin ligase?
Remove a phosphate from its ligand
Remove an ubiquitin from its ligand
Add an ubiquitin to its ligand
Add a phosphate to 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 #4 : Understanding Cytoplasmic Proteins
In regard to cellular membranes, what does it mean to be selectively permeable?
Polarization of the cell membrane allows for passive transport of all foreign molecules or ions
Molecules and ions outside the cell are selected to enter the cell via active or passive transport through the phospholipid bilayer
Polarization of the cell membrane allows for no entrance of foreign molecules or ions
Molecules and ions can pass freely through the phospholipid bilayer
Molecules and ions are always kept to the exterior of the phospholipid bilayer
Molecules and ions outside the cell are selected to enter the cell via active or passive transport through the phospholipid bilayer
A cell must exchange molecules and ions with its surroundings. This process is controlled by the selective permeability of the plasma membrane. Passive transport requires no energy from the cell; molecules like water can diffuse into and out of the cell through the phospholipid bilayer freely by way of osmosis. Other molecules and ions, like sodium, are actively transported across the phospholipid bilayer. This requires ATP created by the cell. Active transport moves solutes against their concentration gradients, which is why it requires energy.
Example Question #2 : Understanding Cytoplasmic Proteins
Which of the following is NOT true of the cytoplasmic protein structures known as tonofibrils?
They are primarily found in endocrine tissues.
The protein filaggrin is thought to hold them together.
They are most typically anchored to the cytoskeleton.
They converge at desmosomes and hemidesmosomes.
They are primarily made of kertain tonofilaments.
They are primarily found in endocrine tissues.
Tonofibrils are groups of keratin tonofilaments (intermediate filaments) most commonly found in the epithelial tissues, not endocrine tissues, and which play an important structural role in cell makeup.
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