CELLULAR AND MOLECULAR BIOLOGY FINAL
EXAM NEWEST 2024 ACTUAL EXAM
Which of the statements is false?
a. Cyclic AMP is generated following activation of the Gs subunit of a
G-protein
b. Four cyclic AMP molecules are produced by each adenylyl cyclase
molecule, which in turn activate one PKA molecule
c. Adenylyl cyclase serves to transduce and amplify the signal form the
G protein coupled receptor (GPCR)
d. The activated PKA molecule is reset to the inactive form of PKA by
phosphodiesterase activity
e. The catalytic subunit of PKA are released from the inactive PKA
molecule following cAMP binding to the regulatory subunit by a
conformational change in PKA – ANSWER- b. Four cyclic AMP
molecules are produced by each adenylyl cyclase molecule, which in
turn activate one PKA molecule
Inositol triphosphate (IP3) leads to the elevation of cytoplasmic
_ ions.
a. Sodium (Na+)
b. Potassium (K+)
c. Calcium (Ca+2)
d. Chloride (Cl-)
e. Proton (H+) – ANSWER- c. Calcium (Ca+2)
Which of the following proteins can be activated by calmodulin in
neurons?
a. Ca+2/CaM-dependent protein kinases II (CaMKII)
b. Protein kinases B (Akt)
c. Phosphatidylinositol (3,4,5)-triphosphate (PIP3)
d. Estrogen receptor beta – ANSWER- a. Ca+2/CaM-dependent protein
kinases II (CaMKII)
signaling is often used to generate a response from a
group of cell of _ type.
a. paracrine, the same
b. autocrine, the same
c. contract dependent, a different
d. contact dependent, the same – ANSWER- b. autocrine, the same
A cell expresses a transmembrane protein that is cleaved at the plasma
membrane to release an extracellular fragment. The fragment binds to
receptor proteins on nearby cells and activates signaling pathways
resulting in altered gene expressions patterns in the cells. What form of
intercellular signaling does this represent?
a. endocrine signaling
b. contract-dependent signaling
c. autocrine signaling
d. synaptic signaling
e. paracrine signaling – ANSWER- e. paracrine signaling
What statement about synaptic signaling is NOT true?
a. signal can be rapidly terminated
b. acts locally at a precise location
c. acts at low local concentrations
d. all of the above
e. rapidly transmit signal over long distances – ANSWER- c. acts at low
local concentrations
What statement about endocrine signals is NOT true?
a. acts broadly over the entire organism
b. signal can be rapidly terminated
c. relies on diffusion and blow flow
d. slowly transmit signal over long distances
e. acts at low concentrations – ANSWER- b. signal can be rapidly
terminated
Ligands are signaling molecules that bind to receptors. Which of the
following statements is true of ligands?
a. Each ligand is only able to bind to one specific receptor
b. Ligands can bind to cell-surface receptors, but they cannot enter the
cell
c. All ligands are proteins
d. Ligands bond to receptor proteins and cause the protein to relay a
message to intercellular proteins – ANSWER- d. Ligands bonds to
receptor proteins and cause the protein to relay a message to intracellular
proteins
Many signal transduction pathways use second messengers to:
a. relay a signal from the outside to the inside of the cell
b. transport a signal through the lipid bilayer portions of the plasma
membrane
c. amplify the message by phosphorylating proteins
d. relay the message from the inside of the membrane throughout the
cytoplasm – ANSWER- d. replay the message from the inside of the
membrane throughout the cytoplasm
What is a G protein?
a. a tyrosine kinase relay protein
b. a protein on the cytoplasmic side of a membrane that become
activated by a receptor protein
c. A membrane bound enzyme that converts ATP to cAMP
d. A specific type of membrane receptor protein – ANSWER- b. a
protein on the cytoplasmic side of a membrane that become activated by
a receptor protein
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