BCH4024 Exam 3 UPDATED QUESTIONS
AND CORRECT ANSWERS
Receptor Protein Kinase (RTK) - CORRECT ANSWER large family of protein
kinases.
a Tyrosine kinase (RTK) - CORRECT ANSWER Cytoplasmic domain is a kinase that
phosphorylates Tyrosine residues on target proteins
RTK
Binding ligand (e.g., insulin) stimulates _____________________________________
leading to a conformational change which opens up active site - CORRECT
ANSWER autophosphorylation
RTK
______________ ________________ results in changes in gene expression leading to
cellular responses such as cell division, programmed cell death, or cell differentiation -
CORRECT ANSWER Signaling cascade
Insulin - CORRECT ANSWER a peptide hormone the regulates both metabolic
enzymes and gene expression
In the RTK pathway, insulin acts as a _____________ - CORRECT ANSWER growth
factor
RTK
When insulin binds its insulin receptor (INSR) the __________________ cascade is
activated. - CORRECT ANSWER MAP kinase (mitogen-activated protein kinase)
,Mitogens - CORRECT ANSWER extracellular signals that induce mitosis and cell
division.
RTK has how many alpha and beta subunits? The binding domain is on what subunit? What
about the cytoplasmic domain? - CORRECT ANSWER 2 and 2
alpha
beta
True or False: In the RTK pathway, insulin enters the cell. - CORRECT
ANSWER false
Excitable cells detect an ___________________, converts it into an _________________ and
pass the signal on - CORRECT ANSWER external signal
electrical signal
When ion channels open,the chemical gradient drives Na+ and Ca+ inward (_____________)
and K+ outward (__________________). The electrical gradient drives Cl− outward
(____________________). - CORRECT ANSWER depolarization
hyperpolarization
depolarization
Depolarization - CORRECT ANSWER increased permeability of Na+ions (less
polar/negative)
,Hyperpolarization - CORRECT ANSWER increased permeability of K+ions (more
polar/negative)
Describe the process of voltage gated ion channels - CORRECT ANSWER 1) signal
causes Na+ channels to open which depolarizes the cell. In turn, more Na+ channels open
(Na in) (propagation)
2) K+ channels open which depolarizes the cell (K out)
3) Ca2+ channels open allowing it into the cell
4) Ca causes vesicles containing acetylcholine to fuse with the cell membrane, allowing
acetylcholine into the synaptic cleft
5) acetylcholine binds to receptors on the postsynaptic cell which allows Na and Ca into the
cell leading to depolarization (propagating the signal down the neuron)
What binds to receptors in the nucleus to alter gene expression? - CORRECT
ANSWER Steroid, retinoid, and thyroid hormones
Describe how hormones alter gene expression. - CORRECT ANSWER 1) Because
they are hydrophobic, hormones can readily diffuse into the plasma membrane and enter the
nucleus
2) They bind to a receptor, changing conformation, making a homo/heterodimer complex
3) This complex binds to regions on DNA called hormone response elements (HREs)
4) This results in enhanced expression of specific genes by enhancing mRNA production and
regulating transcription (functions as transcription factor)
slow process
Rhodopsin is a ________________ and is composed of ______________ and
_______________ - CORRECT ANSWER GPCR
retinal + opsin
, When a photon is absorbed by retinal,the energy causes a change of 11-_____-retinal to all-
_____-retinal. - CORRECT ANSWER cis trans
Rhodopsin
This change in the chromophore (Cis to trans) forces a conformational change in rhodopsin
which activates _____________ a trimeric G protein complex - CORRECT
ANSWER transducin(T)
After transducin is activated, the T alpha subunit is _____________ and ________ is
replaced with ________ - CORRECT ANSWER detached
GDP GTP
Rhodopsin
Tα activates a ________________ _______________, leading to a drop in _________
(conversionof c GMPto 5′-GMP). The cell then become ________polarized - CORRECT
ANSWER cGMP phosphodiesterase
[cGMP]
hyper
Metabolism - CORRECT ANSWER The overall process through which living systems
acquire and utilizethe free energy they need to carry out their various functions.
Relies on coupling reactions
Reactants, intermediates, and products are ... - CORRECT ANSWER metabolites
AND CORRECT ANSWERS
Receptor Protein Kinase (RTK) - CORRECT ANSWER large family of protein
kinases.
a Tyrosine kinase (RTK) - CORRECT ANSWER Cytoplasmic domain is a kinase that
phosphorylates Tyrosine residues on target proteins
RTK
Binding ligand (e.g., insulin) stimulates _____________________________________
leading to a conformational change which opens up active site - CORRECT
ANSWER autophosphorylation
RTK
______________ ________________ results in changes in gene expression leading to
cellular responses such as cell division, programmed cell death, or cell differentiation -
CORRECT ANSWER Signaling cascade
Insulin - CORRECT ANSWER a peptide hormone the regulates both metabolic
enzymes and gene expression
In the RTK pathway, insulin acts as a _____________ - CORRECT ANSWER growth
factor
RTK
When insulin binds its insulin receptor (INSR) the __________________ cascade is
activated. - CORRECT ANSWER MAP kinase (mitogen-activated protein kinase)
,Mitogens - CORRECT ANSWER extracellular signals that induce mitosis and cell
division.
RTK has how many alpha and beta subunits? The binding domain is on what subunit? What
about the cytoplasmic domain? - CORRECT ANSWER 2 and 2
alpha
beta
True or False: In the RTK pathway, insulin enters the cell. - CORRECT
ANSWER false
Excitable cells detect an ___________________, converts it into an _________________ and
pass the signal on - CORRECT ANSWER external signal
electrical signal
When ion channels open,the chemical gradient drives Na+ and Ca+ inward (_____________)
and K+ outward (__________________). The electrical gradient drives Cl− outward
(____________________). - CORRECT ANSWER depolarization
hyperpolarization
depolarization
Depolarization - CORRECT ANSWER increased permeability of Na+ions (less
polar/negative)
,Hyperpolarization - CORRECT ANSWER increased permeability of K+ions (more
polar/negative)
Describe the process of voltage gated ion channels - CORRECT ANSWER 1) signal
causes Na+ channels to open which depolarizes the cell. In turn, more Na+ channels open
(Na in) (propagation)
2) K+ channels open which depolarizes the cell (K out)
3) Ca2+ channels open allowing it into the cell
4) Ca causes vesicles containing acetylcholine to fuse with the cell membrane, allowing
acetylcholine into the synaptic cleft
5) acetylcholine binds to receptors on the postsynaptic cell which allows Na and Ca into the
cell leading to depolarization (propagating the signal down the neuron)
What binds to receptors in the nucleus to alter gene expression? - CORRECT
ANSWER Steroid, retinoid, and thyroid hormones
Describe how hormones alter gene expression. - CORRECT ANSWER 1) Because
they are hydrophobic, hormones can readily diffuse into the plasma membrane and enter the
nucleus
2) They bind to a receptor, changing conformation, making a homo/heterodimer complex
3) This complex binds to regions on DNA called hormone response elements (HREs)
4) This results in enhanced expression of specific genes by enhancing mRNA production and
regulating transcription (functions as transcription factor)
slow process
Rhodopsin is a ________________ and is composed of ______________ and
_______________ - CORRECT ANSWER GPCR
retinal + opsin
, When a photon is absorbed by retinal,the energy causes a change of 11-_____-retinal to all-
_____-retinal. - CORRECT ANSWER cis trans
Rhodopsin
This change in the chromophore (Cis to trans) forces a conformational change in rhodopsin
which activates _____________ a trimeric G protein complex - CORRECT
ANSWER transducin(T)
After transducin is activated, the T alpha subunit is _____________ and ________ is
replaced with ________ - CORRECT ANSWER detached
GDP GTP
Rhodopsin
Tα activates a ________________ _______________, leading to a drop in _________
(conversionof c GMPto 5′-GMP). The cell then become ________polarized - CORRECT
ANSWER cGMP phosphodiesterase
[cGMP]
hyper
Metabolism - CORRECT ANSWER The overall process through which living systems
acquire and utilizethe free energy they need to carry out their various functions.
Relies on coupling reactions
Reactants, intermediates, and products are ... - CORRECT ANSWER metabolites
