BS 161 Exam 3 Questions with Correct Answers Latest Update 2025/2026
Transduction - Answers Cell converts an extracellular signal to an intracellular response
Ligand - Answers Signaling molecule that binds to a receptor protein
G protein - Answers A protein that binds to GTP or GDP
Kinase - Answers An enzyme that catalyzes the transfer of a phosphate group from ATP to a
substrate
G protein coupled with GDP - Answers Inactive
Phosphorylation - Answers Adding a phosphate
Dephosphorylation - Answers Removing a phosphate
Hydroylsis - Answers Water molecule breaks a chemical bond with GTP
Phosphatase - Answers An enzyme that remove a phosphate group from another molecule
Active form - Answers Molecules change shape or are chemically modified to propagate signal.
Initiates a cascade of cellular events leading to a response
Inactive form - Answers Signaling molecules are in a stable state and not transmitting signals
Amplification - Answers Small initial signal that triggers a large response by activating a chain
reaction of molecules, greatly increasing the strength of the signal
Intracellular receptors - Answers Receptors in cytosol or nucleus
Cell surface receptors - Answers Polar ligands bind to the receptor, which keeps the receptors
on the cell surface
Chromosome - Answers A structure of DNA and proteins in cells (observed in M phase)
Chromatin - Answers Loosely packaged form of DNA and proteins found in interphase and G0
cell
Homologous chromosome - Answers A pair of chromosomes that contain the same genes in
the same order, with overall 95% sequence similarity
Sister chromatid - Answers One of two identical copies of a DNA sequence, formed from DNA
replication, that remain attached at the centromere by cohesion proteins until anaphase of
mitosis
Centromere - Answers the part of a chromosome that links sister chromatids
Kinetochores - Answers Proteins that attach to the centromere
Transduction - Answers Cell converts an extracellular signal to an intracellular response
Ligand - Answers Signaling molecule that binds to a receptor protein
G protein - Answers A protein that binds to GTP or GDP
Kinase - Answers An enzyme that catalyzes the transfer of a phosphate group from ATP to a
substrate
G protein coupled with GDP - Answers Inactive
Phosphorylation - Answers Adding a phosphate
Dephosphorylation - Answers Removing a phosphate
Hydroylsis - Answers Water molecule breaks a chemical bond with GTP
Phosphatase - Answers An enzyme that remove a phosphate group from another molecule
Active form - Answers Molecules change shape or are chemically modified to propagate signal.
Initiates a cascade of cellular events leading to a response
Inactive form - Answers Signaling molecules are in a stable state and not transmitting signals
Amplification - Answers Small initial signal that triggers a large response by activating a chain
reaction of molecules, greatly increasing the strength of the signal
Intracellular receptors - Answers Receptors in cytosol or nucleus
Cell surface receptors - Answers Polar ligands bind to the receptor, which keeps the receptors
on the cell surface
Chromosome - Answers A structure of DNA and proteins in cells (observed in M phase)
Chromatin - Answers Loosely packaged form of DNA and proteins found in interphase and G0
cell
Homologous chromosome - Answers A pair of chromosomes that contain the same genes in
the same order, with overall 95% sequence similarity
Sister chromatid - Answers One of two identical copies of a DNA sequence, formed from DNA
replication, that remain attached at the centromere by cohesion proteins until anaphase of
mitosis
Centromere - Answers the part of a chromosome that links sister chromatids
Kinetochores - Answers Proteins that attach to the centromere
