wk 3 - Hormones and Receptors Flashcards
What is the name of the protein that adds phosphate groups to other proteins?
a) Amylase
b) Phosphatase
c) Kinase
d) Lipase
e) Tyrosine
c) Kinase
The following are possible processes that insulin can promote EXCEPT:
a) Glycolysis
b) Gluconeogenesis
c) Glycogenesis
d) Lipogenesis
e) Protein synthesis
b) Gluconeogenesis
1?
GDP
(guanine diphosphate)
Receptor activation by hormones lead to a second messenger pathway and a ________________ of the hormonal signal.
Receptor activation by hormones lead to a second messenger pathway and a cascade / amplification of the hormonal signal.
The hypothalamus stimulates the pituitary glands to stimulate TSH, which stimulates the thyroid gland to produce the hormones T3 and T4, which when rise in the blood cause inhibition of the whole process.
a) Humoral stimuli
b) Hormonal stimuli
c) Growth hormone
d) Neural stimuli
b) Hormonal stimuli
Insulin facilitates glucose uptake in ——
a) Adipocytes
b) Liver
c) Muscle
d) Pancreas
c) Muscle
name the form of insulin:
Chain A + Chain B + Chain C + signal sequence =
Chain A + Chain B + Chain C + signal sequence = Preproinsulin
The active α-subunit of the ____ ______ _______ binds and activates adenylate cyclase that leads to increases intracellular levels of cAMP
The active α-subunit of the GTP binding protein binds and activates adenylate cyclase that leads to increases intracellular levels of cAMP
an increase in insulin can inhibit the activity of what 3 pathways?
- gluconeogenesis
- lipolysis
- glycogenolysis
to turn a phosphatase receptor off, it needs to be _________________
to turn a phosphatase receptor off, it needs to be dephosphorylated
When the insulin binds to its receptor, it causes conformational changes in the receptor leading to ___________ of each β-subunit.
When the insulin binds to its receptor, it causes conformational changes in the receptor leading to transphosphorylation of each β-subunit.
Preproinsulin is composed of what 3 structures:
- signal sequence
- c-peptide
- insulin.
the hormone that circulates through the blood to bind to a receptor is also called the ____ messenger, while the hormone signalled by the receptor complex within the cell is also called the ____ messenger
the hormone that circulates through the blood to bind to a receptor is also called the 1st messenger, while the hormone signalled by the receptor complex within the cell is also called the 2nd messenger
3?
ATP
What is the second messenger to be phosphorylated in the insulin receptor mechanism of action?
a) cAMP
b) G-protein
c) IRS-1
d) IRS-2
e) IRS-3
c) IRS-1
(insulin receptor substrate-1)
What is the role of tyrosine kinase on the insulin receptor?
a) Dephosphorylation of tyrosine
b) Oxidation of tyrosine
c) Phosphorylation of tyrosine
d) Reduction of tyrosine
c) Phosphorylation of tyrosine
insulin release causes ______________ inhibition in the liver and kidney
insulin release causes gluconeogenesis inhibition in the liver and kidney
Epinephrine (1st messenger) is one of many hormones that is _________ and therefore unable to cross the hydrophobic plasma membranes of its target cells, instead it binds to a ________ located in the plasma membrane and does not enter the cell.
Epinephrine (1st messenger) is one of many hormones that is Hydrophlic and therefore unable to cross the hydrophobic plasma membranes of its target cells, instead it binds to a receptor protein located in the plasma membrane and does not enter the cell.
Glucagon inhibits which reaction?
a) Gluconeogenesis
b) Lipolysis
c) Protein lysis
d) Protein synthesis
d) Protein synthesis
increased insulin causes ________ activity of:
Gluconeogenic enzymes
- Glucose-6-phosphatase
- fructose-1,6-bisphosphatase
- pyruvate carboxylase
- Phosphoenolpyruvate carboxykinase
Glycogenolytic
• Glycogen phosphorylase
Lipolytic
• Triglyceride lipase
increased insulin causes decreased activity of:
Signal sequence plus c-peptide plus proinsulin is called ——–
a) Proinsulin
b) Glucagon
c) Insulin
d) Preproinsulin
d) Preproinsulin
insulin release _________ proteogenesis and ________ proteolysis- especially in muscle
insulin release promotes proteogenesis and inhibits proteolysis - especially in muscle
A hormone’s action can be switched off by inactivating the 2nd messenger cAMP (inactivating the 2nd messenger) with another hormone that produces ——-
a) Dephosphorylation
b) Hydrolase
c) Phosphodiesterase
d) Phosphorylation
c) Phosphodiesterase
__________ is a Greek name and it means to “stir up or excite”
Hormone
___________ are examples of kidney hormones.
a) Gastrin and histamine
b) Glucagon and Insulin
c) Thyroxine and triiodothyronine
d) Renin and calcitriol
d) Renin and calcitriol
The sympathetic nervous system directly stimulates the adrenal medulla to release the hormones epinephrine and norepinephrine in response to stress, which burst the energy required by the body. This is an example of ——-
a) Humoral stimuli
b) Hormonal stimuli
c) Growth hormone
d) Neural stimuli
d) Neural stimuli
How does insulin clear glucose from the blood? The following are possible processes that insulin can inhibit EXCEPT:
a) Glycolysis
b) Gluconeogenesis
c) Glycogenolysis
d) Lipolysis
a) Glycolysis
insulin release ________ glycogenesis and ________ glycogenolysis
- especially in the liver and muscle tissue which have significant stores
insulin release promotes glycogenesis and inhibits glycogenolysis
- especially in the liver and muscle tissue which have significant stores
Glucagon and insulin are examples of hormones derived from?
a) Amino acid derivatives
b) Polypeptides
c) Steroids
d) Biologically potent
b) Polypeptides
Insulin promotes which reaction?
a) Gluconeogenesis
b) Lipolysis
c) Protein lysis
d) Protein synthesis
d) Protein synthesis
name the polypeptide:
- Small 29 amino acid (3.5kDa) polypeptide chain
- Largely a-helical, flexible molecule
- Synthesised by α-cells of Islets of Langerhans
- Prepro and pro hormone precursors
glucagon
The hormone ————– is synthesized by the α-cells in the pancreas in response to decreased plasma glucose level.
a) Epinephrine
b) Glucagon
c) Insulin
d) TSH
e) T3
b) Glucagon
an increase in insulin can promote the activity of what 4 pathways?
- glycolysis
- glycogenesis
- lipogenesis
- protein synthesis
name the form of insulin:
Chain A + Chain B + Chain C =
Chain A + Chain B + Chain C = Proinsulin
What is the role of the phosphorylated second messenger (IRS-1) in the insulin’s receptor mechanism of action?
It activates other events in the insulin action cascade.
increased insulin causes ________ activity of:
Glycolytic enzymes
- Glucokinase
- Phosphofructokinase
- Pyruvate kinase
Glycogenic
• Glycogen synthase
Lipogenic
- Pyruvate dehydrogenase
- Acetyl CoA carboxylase
- Fatty acid synthase
increased insulin causes increased activity of:
The hypothalamus stimulates the pituitary glands to stimulate TSH, which stimulates the thyroid gland to produce the hormones ____________, which when rise in the blood cause inhibition of the whole process.
a) Epinephrine and norepinephrine
b) Growth hormones
c) T3 and T4
d) TSH and T4
The hypothalamus stimulates the pituitary glands to stimulate TSH, which stimulates the thyroid gland to produce the hormones T3 and T4, which when rise in the blood cause inhibition of the whole process.
One _________ can initiate a cascade of many reactions at the same time, which saves the cell energy.
One hormone can initiate a cascade of many reactions at the same time, which saves the cell energy.
insulin release _________ lipogenesis and _________ lipolysis - especially in adipose tissue and the liver
insulin release promotes lipogenesis and inhibits lipolysis - especially in adipose tissue and the liver
2?
GTP
(guanine triphosphate)
Long acting insulin has a relatively ———- molecular weight.
a) High
b) Low
c) Medium
a) High
The hormone can be turned off by the following EXCEPT:
a) Changing the conformation of the receptor, so it won’t recognize the hormone
b) Dissociate the hormone-receptor complex
c) Inactivate the messenger
d) Inactivate the enzyme
d) Inactivate the enzyme
Receptors are usually large and complex. They usually have _____ affinity and are present in very ____ concentrations.
Receptors are usually large and complex. They usually have high affinity and are present in very low concentrations.
Hormones can be turned off/inactivated by changing the ___________ of the receptor, so it won’t recognize the hormone and won’t bind to it.
Hormones can be turned off/inactivated by changing the conformation of the receptor, so it won’t recognize the hormone and won’t bind to it.
The enzyme ______ ______ __ is in charge of phosphorylation of other enzymes.
The enzyme protein kinase A is in charge of phosphorylation of other enzymes.
T3 & T4 are examples of hormones derived from?
a) Amino acid derivatives
b) Polypeptides
c) Steroids
d) Biologically potent
a) Amino acid derivatives
___________ are chemical substances synthesised in small amounts by an endocrine tissue.
a) Bones
b) Enzymes
c) Hormones
d) Receptors
c) Hormones
Glucagon promotes which reaction?
a) Gluconeogenesis
b) Glycolysis
c) Lipid synthesis
d) Protein synthesis
a) Gluconeogenesis
______ mediates all of the downstream metabolic actions of glucagon
cAMP mediates all of the downstream metabolic actions of glucagon
5?
Hormone
Enzyme activities can be carefully coordinated & finely controlled through combinations of _______ and ________ regulation.
Enzyme activities can be carefully coordinated & finely controlled through combinations of allosteric and hormonal regulation.
Glucagon acts by first binding to a receptor that promotes the activation of a ______________
Glucagon acts by first binding to a receptor that promotes the activation of a GTP binding protein
Insulin’s receptor is comprised of:
a) One alpha and one beta subunit
b) Three alpha and three beta subunits
c) Two alpha and one beta subunit
d) Two alpha and two beta subunits
d) Two alpha and two beta subunits
The hormone ————– is synthesized by the β-cells in the pancreas in response to increased plasma glucose level.
a) Epinephrine
b) Glucagon
c) Insulin
d) TSH
e) T3
c) Insulin
The enzyme that forms glycogen is called ——-
a) Glycogen phosphorylase
b) Glycogen phosphorylase-P
c) Glycogen synthase
d) Protein kinase-A
e) Glycogen synthase-P
c) Glycogen synthase
Insulin’s receptor subunits are stabilized by ———– bonds.
a) Coordinate
b) Disulfide
c) Hydrogen
d) Ionic
b) Disulfide
Glycogen phosphorylase-P and glycogen synthase are both in their active form.
a) True
b) False
true
4?
cAMP
(cyclic adenosine monophospate)
All of the following stimulates alpha cell to produce glucagon EXCEPT:
a) Certain amino acids
b) Insulin
c) Low blood glucose
d) Somatostatin
e) Some GI hormones
d) Somatostatin
The hormone ————– is secreted in response to increased blood glucose level.
a) T3
b) Glucagon
c) Insulin
d) TSH
c) Insulin
Activated G-protein with GTP binds to _____________ , which in turn is activated to catalyse the formation of ______ (second messenger) using 1 ____.
Activated G-protein with GTP binds to Adenylate cyclase, which in turn is activated to catalyse the formation of cAMP (second messenger) using 1 ATP.
_____ acting insulin has a relatively high molecular weight, whereas ______ acting insulin has a relatively low molecular weight.
Long acting insulin has a relatively high molecular weight, whereas Fast acting insulin has a relatively low molecular weight.
Glucagon acts primarily in _____ and __________. It has no action in muscle.
Glucagon acts primarily in liver and adipose tissue. It has no action in muscle.
Calcium is controlling muscles contraction and relaxation. In case of low calcium in blood (hypocalcaemia), parathyroid glands secrete ———– to resorb calcium from bones and the kidneys. Once calcium is increased in blood, —– secretion is inhibited.
a) PTH
b) T3
c) T4
d) TSH
a) PTH
___________ inhibits both Insulin and glucagon
Somatostatin inhibits both Insulin and glucagon
Hormones act by binding to _______ ________ (the antennae of cells).
Hormones act by binding to target receptors (the antennae of cells).
the 3 mechanisms for inhibition of metabolic pathways include:
- __________ the messenger
- switching on/of the receptor by _____________________ processes - (receptor modulation)
- ____________ of the number of receptors
the 3 mechanisms for inhibition of metabolic pathways include:
- inactivating (‘shooting’) the messenger
- switching on/of the receptor by phosphorylation/dephosphorylation processes (receptor modulation)
- down regulation of the number of receptors
state whether glucagon either promotes or inhibits the following metabolic pathways:
- _______ Lipolysis (Liver and Adipose)
- _______ Glycogenolysis (Liver)
- _______ Glycogen Synthesis (Liver)
- _______ Gluconeogenesis (Liver)
- _______ Glycolysis (Liver)
- Promotes Lipolysis (Liver and Adipose)
- Promotes Glycogenolysis (Liver)
- Inhibits Glycogen Synthesis (Liver)
- Promotes Gluconeogenesis (Liver)
- Inhibits Glycolysis (Liver)
- No action in Muscle!
cAMP binds to an inactive protein kinase A to activate it. Activated protein kinase then activates the enzyme phosphorylase, which converts ________ to glucose 6-phosphate, and then to ________, which is finally released into the ___________.
cAMP binds to an inactive protein kinase A to activate it. Activated protein kinase then activates the enzyme phosphorylase, which converts glycogen to glucose 6-phosphate, and then to glucose, which is finally released into the bloodstream.
The actions of ________ and _______ combine to provide a close check and narrow limits for blood glucose levels
The actions of insulin and glucagon combine to provide a close check and narrow limits for blood glucose levels
Calcium is controlling muscle contraction and relaxation. In the case of low blood calcium (—————-), parathyroid glands secrete ———– to ———– calcium from bones & the kidneys. Once calcium concentration is increased in blood, ——– secretion is inhibited.
Calcium is controlling muscle contraction and relaxation. In the case of low blood calcium (Hypocalcaemia), parathyroid glands secrete PTH to reabsorb calcium from bones & the kidneys. Once calcium concentration is increased in blood, PTH secretion is inhibited.
Insulin inhibits which reaction?
a) Gluconeogenesis
b) Glycolysis
c) Lipid synthesis
d) Protein synthesis
a) Gluconeogenesis
Fast acting insulin has a relatively ———- molecular weight.
a) High
b) Low
c) Medium
b) Low
Insulin facilitates glycogen synthesis in ——
a) Adipocytes
b) Liver
c) Muscle
d) Pancreas
b) Liver
All of the following stimulates Beta cell to produce insulin EXCEPT:
a) Certain amino acids
b) High blood glucose
c) Somatostatin
d) Glucagon
e) Some GI hormones
c) Somatostatin
A rise in blood glucose levels triggers the pancreatic release of insulin. Insulin causes blood glucose levels to drop, which signals the pancreas to stop producing insulin. This is an example of ————–
a) Humoral stimuli
b) Hormonal stimuli
c) Growth hormone
d) Neural stimuli
a) Humoral stimuli
_________ has no action in muscle as it has no ________ receptor.
glucagon has no action in muscle as it has no glucagon receptor.
____________ are examples of pancreatic hormones.
a) Gastrin and histamine
b) Glucagon and Insulin
c) Thyroxine and triiodothyronine
d) Renin and calcitriol
b) Glucagon and Insulin
The enzyme that cleaves glycogen is called ——-
a) Glycogen phosphorylase
b) Glycogen phosphorylase-P
c) Glycogen synthase
d) Protein kinase-A
e) Glycogen synthase-P
b) Glycogen phosphorylase-P
_______ and ________ have an opposite action in regulation of blood glucose level.
Insulin and glucagon have an opposite action in regulation of blood glucose level.
name the form of insulin:
Chain A + Chain B =
Chain A + Chain B = Mature insulin
Insulin facilitates glycerol synthesis in ——
a) Adipocytes
b) Liver
c) Muscle
d) Pancreas
a) Adipocytes
One hormone will signal a cascade of reactions at the same time, which saves the cell _________
One hormone will signal a cascade of reactions at the same time, which saves the cell energy
In the liver cell, once the first messenger/hormone binds to the receptor protein, a _________ on the inner side of the cell membrane bound to the receptor is activated. Once this protein’s GDP is replaced with ____, the sub unit is activated.
In the liver cell, once the first messenger/hormone binds to the receptor protein, a G protein (3 subunits) on the inner side of the cell membrane bound to the receptor is activated. Once this protein’s GDP is replaced with GTP, the sub unit is activated.
What is the right order to produce insulin in pancreatic cell?
a) Mature insulin then preproinsulin then proinsulin
b) Preproinsulin then mature insulin then proinsulin
c) Preproinsulin then proinsulin then mature insulin
d) Proinsulin then preproinsulin then mature insulin
c) Preproinsulin then proinsulin then mature insulin
________ are usually large, complex proteins, present in low abundance relative to the hormone, and bind the hormone with high affinity.
Receptors are usually large, complex proteins, present in low abundance relative to the hormone, and bind the hormone with high affinity.
Glucose uptake is promoted in most tissues EXCEPT:
a) Adipose tissues
b) Kidney
c) Liver
d) Muscles
c) Liver
_______________ are examples of thyroid hormones.
a) Gastrin and histamine
b) Glucagon and Insulin
c) Thyroxine and triiodothyronine
d) Renin and calcitriol
c) Thyroxine and triiodothyronine
