BS 161 MSU EXAM PREP TEST 2026
DETAILED SOLUTIONS GRADED A+
⫸ signal transduction. Answer: The process in which an extracellular
molecule acts as a signal to activate a receptor, which transmits
information through the cytoplasm.
⫸ response. Answer: A change in cellular behavior, such as
activation of enzymes or genes, following a signal.
⫸ termination. Answer: In protein translation, the time at which the
addition of amino acids stops and the completed polypeptide chain is
released from the ribosome. In cell communication, the stopping of a
signal.
⫸ endocrine signaling. Answer: Signaling by molecules that travel
through the bloodstream.
⫸ paracrine signaling. Answer: Signaling by a molecule that travels
a short distance to the nearest neighboring cell to bind its receptor and
deliver its message.
⫸ growth factor. Answer: Any one of a group of small, soluble
molecules, usually the signal in paracrine signaling, that affect cell
growth, cell division, and changes in gene expression.
,⫸ autocrine signaling. Answer: Signaling between different parts of
a cell; the signaling cell and the responding cell are one and the same.
⫸ Neurons have what transmembrane protein?. Answer: delta
⫸ Cells with activated notch transmembrane proteins become?.
Answer: glial cells
⫸ What type of molecule is the delta protein?. Answer: signaling
⫸ Is notch a signaling molecule or receptor?. Answer: receptor
⫸ ligand. Answer: Alternative term for a signaling molecule that
binds with a receptor, usually a protein.
⫸ ligand-binding site. Answer: The specific location on the receptor
protein where a signaling molecule binds.
⫸ G protein-coupled receptor. Answer: A receptor that couples to G
proteins, which bind to the guanine nucleotides GTP and GDP.
⫸ G protein. Answer: A protein that binds to the guanine nucleotides
GTP and GDP.
,⫸ receptor kinase. Answer: A receptor that is an enzyme that adds a
phosphate group to another molecule.
⫸ phosphatase. Answer: An enzyme that removes a phosphate group
from another molecule.
⫸ ion channels. Answer: Cell-surface receptors that open and close,
thereby altering the flow of ions across the plasma membrane.
⫸ What two characteristics do G-protein coupled receptors have?.
Answer: First, they have a similar structure, consisting of a single
polypeptide chain that has seven transmembrane spanning regions,
with the ligand-binding site on the outside of the cell and the portion
that binds to the G protein on the inside of the cell.
Second, when activated, they associate with a G protein.
⫸ When a ligand binds to a G protein-coupled receptor, the receptor
in turn binds to and activates a G protein by causing it to release
______ and bind ______?. Answer: GDP;GTP
⫸ G proteins are active or turned on when bound to ____? G
proteins are inactive or turned off when bound to ____?. Answer:
GTP;GDP
⫸ Some G proteins are composed of three subunits, called the?.
Answer: Alpha, beta, and gamma subunits.
, ⫸ The _____ subunit is the part of the G protein that binds to either
GDP or GTP?. Answer: alpha
⫸ When GDP bound to the α subunit is replaced by GTP, the ____
subunit separates from the _____ and ____ subunits?. Answer: Alpha;
Beta; Gamma
⫸ Is the term "G protein" just a shorter name for a G protein-coupled
receptor?. Answer: No. A G protein-coupled receptor is a
transmembrane receptor that interacts with a G protein located inside
the cell on the cytoplasmic side of the plasma membrane.
⫸ denylyl cyclase converts the nucleotide ATP into _____?. Answer:
cyclic AMP (cAMP)
⫸ denylyl cyclase converts the nucleotide ATP into _____?. Answer:
cyclic AMP (cAMP)
⫸ First messenger. Answer: First messengers transmit signals from
outside the cell to a receptor.
⫸ binding affinity. Answer: The tightness of the binding between the
receptor and the signaling molecule.
⫸ Kit. Answer: Is a receptor kinase and is important for the
production of pigment in skin, feathers, scales, and hair.
DETAILED SOLUTIONS GRADED A+
⫸ signal transduction. Answer: The process in which an extracellular
molecule acts as a signal to activate a receptor, which transmits
information through the cytoplasm.
⫸ response. Answer: A change in cellular behavior, such as
activation of enzymes or genes, following a signal.
⫸ termination. Answer: In protein translation, the time at which the
addition of amino acids stops and the completed polypeptide chain is
released from the ribosome. In cell communication, the stopping of a
signal.
⫸ endocrine signaling. Answer: Signaling by molecules that travel
through the bloodstream.
⫸ paracrine signaling. Answer: Signaling by a molecule that travels
a short distance to the nearest neighboring cell to bind its receptor and
deliver its message.
⫸ growth factor. Answer: Any one of a group of small, soluble
molecules, usually the signal in paracrine signaling, that affect cell
growth, cell division, and changes in gene expression.
,⫸ autocrine signaling. Answer: Signaling between different parts of
a cell; the signaling cell and the responding cell are one and the same.
⫸ Neurons have what transmembrane protein?. Answer: delta
⫸ Cells with activated notch transmembrane proteins become?.
Answer: glial cells
⫸ What type of molecule is the delta protein?. Answer: signaling
⫸ Is notch a signaling molecule or receptor?. Answer: receptor
⫸ ligand. Answer: Alternative term for a signaling molecule that
binds with a receptor, usually a protein.
⫸ ligand-binding site. Answer: The specific location on the receptor
protein where a signaling molecule binds.
⫸ G protein-coupled receptor. Answer: A receptor that couples to G
proteins, which bind to the guanine nucleotides GTP and GDP.
⫸ G protein. Answer: A protein that binds to the guanine nucleotides
GTP and GDP.
,⫸ receptor kinase. Answer: A receptor that is an enzyme that adds a
phosphate group to another molecule.
⫸ phosphatase. Answer: An enzyme that removes a phosphate group
from another molecule.
⫸ ion channels. Answer: Cell-surface receptors that open and close,
thereby altering the flow of ions across the plasma membrane.
⫸ What two characteristics do G-protein coupled receptors have?.
Answer: First, they have a similar structure, consisting of a single
polypeptide chain that has seven transmembrane spanning regions,
with the ligand-binding site on the outside of the cell and the portion
that binds to the G protein on the inside of the cell.
Second, when activated, they associate with a G protein.
⫸ When a ligand binds to a G protein-coupled receptor, the receptor
in turn binds to and activates a G protein by causing it to release
______ and bind ______?. Answer: GDP;GTP
⫸ G proteins are active or turned on when bound to ____? G
proteins are inactive or turned off when bound to ____?. Answer:
GTP;GDP
⫸ Some G proteins are composed of three subunits, called the?.
Answer: Alpha, beta, and gamma subunits.
, ⫸ The _____ subunit is the part of the G protein that binds to either
GDP or GTP?. Answer: alpha
⫸ When GDP bound to the α subunit is replaced by GTP, the ____
subunit separates from the _____ and ____ subunits?. Answer: Alpha;
Beta; Gamma
⫸ Is the term "G protein" just a shorter name for a G protein-coupled
receptor?. Answer: No. A G protein-coupled receptor is a
transmembrane receptor that interacts with a G protein located inside
the cell on the cytoplasmic side of the plasma membrane.
⫸ denylyl cyclase converts the nucleotide ATP into _____?. Answer:
cyclic AMP (cAMP)
⫸ denylyl cyclase converts the nucleotide ATP into _____?. Answer:
cyclic AMP (cAMP)
⫸ First messenger. Answer: First messengers transmit signals from
outside the cell to a receptor.
⫸ binding affinity. Answer: The tightness of the binding between the
receptor and the signaling molecule.
⫸ Kit. Answer: Is a receptor kinase and is important for the
production of pigment in skin, feathers, scales, and hair.
