Bio 245 Klesath Exam 1 NCSU QUESTIONS
AND ANSWERS ALL CORRECT
3 reflex mechanisms that stimulate hormone secretion Correct Answer: 1.Hormonal Stimulation:
stimulus for release of hormones by the binding of another hormone (eg the TSH from anterior
pituitary binds to thyroid gland to release TH)
2.Humoral Stimulation: release of hormone in response to change of blood nutrient levels (eg
blood glucose levels rise so insulin is released from pancreas, or fall and glucagon is released)
3.Neural Stimulation: direct stimulation from nervous system to endocrine gland (eg epinephrine
and norepinephrine by adrenal medulla during fight or flight)
Hormonal Stimulation Correct Answer: Stimulus for release of hormones by the binding of
another hormone (eg the TSH from anterior pituitary binds to thyroid gland to release TH)
Humoral Stimulation Correct Answer: release of hormone in response to change of blood
nutrient levels (eg blood glucose levels rise so insulin is released from pancreas, or fall and
glucagon is released)
Neural Stimulation Correct Answer: direct stimulation from nervous system to endocrine gland
(eg epinephrine and norepinephrine by adrenal medulla during fight or flight)
Steroids Correct Answer: lipid soluble molecules synthesized by cholesterol
1. Gonads (Estrogen, Progesterone, Testosterone)
2. Adrenal Cortex hormones (Corticosteroids like cortisol, mineralocorticoids, aldosterone)
Biogenic Amines Correct Answer: modified amino acids, water soluble (except thyroid)
1. Catecholamines (epinephrine and norepinephrine)
2. Thyroid Hormone → lipid soluble
3. Melatonin
Proteins Correct Answer: most hormones, small chains of amino acids, water soluble
1. Small peptides and large polypeptides
2. Glycoproteins
Local Hormones Correct Answer: DO NOT circulate in blood, so only affect either same cell
that produced them (autocrine) or neighboring cells (Paracrine)
1. Eicosanoids: synthesized through enzymatic cascade, Phospholipase A2 removes fatty acid
from phospholipid within the plasma membrane
--> prostaglandins
Prostaglandins Correct Answer: -Famous eicosanoid
-are diverse group: synthesized by most tissues in the body
-Stimulate pain receptors, reduce fever, increase inflammatory response
, Lipid soluble hormones: Correct Answer: Can cross membrane, but needs carrier protein while
circulating in blood, once unbound they can enter the nucleus
a. Has a longer half-life bc protected by carrier proteins
b. Once inside the cells, hormone binds to intracellular receptor either in nucleus of cytosol
c. Once bound, forms a hormone receptor complex which interacts with DNA directly in regions
called Hormone Response Element (HRE)
d. Initiates transcription/translation and production of a new protein
Water soluble hormones Correct Answer: Travel free in blood so shorter half-life, cannot enter
plasma membrane so binds to a membrane bound receptor
a. Second messengers begin a signal transduction pathway, which can cause an amplified signal
G protein activation by water-soluble hormones Correct Answer: a. Hormone binds to G-Protein
and activates it when GDP→ GTP
b. Active G-Protein is released and receptor moves along inside plasma mebrane, either to
activate or inhibit other intracellular cascades
Adenylate Cyclase Correct Answer: a. Hormone binds to G-Protein and activates it when
GDP→ GTP
b. Active G-Protein is released and receptor moves along inside plasma mebrane, either to
activate or inhibit other intracellular cascades
c. Using ATP, cAMP is created and activates protein kinase A, which will phosphorylate things
→ small concentration of hormone can have large effect on cell
Phospholipase C Correct Answer: i. Phospholipase C is enzyme activated by G-protein
ii. Splits into PIP2 and second messengers, DAG and IP3
iii. DAG activates kinase C
iv. IP3 leaves membrane and causes increase in Ca2 in cytosol which can directly affect or act as
3rd messenger
Upregulation Correct Answer: When the amount of hormones is small, then the number of
receptors increase in order to increase the sensitivity and obtain more of the hormones
--> Occurs with changes in development, cell cycle, and cell activity
Downregulation Correct Answer: If there is an abundent amount of hormone in the blood, then
the number of receptors decrease
--> Occurs with changes in development, cell cycle, and cell activity
Synergistic Hormone Interaction Correct Answer: hormones work together to have a greater
effect
a. 1+1=3, estrogen and progesterone together have a stronger effect than individually
Permissive Hormone Interaction Correct Answer: first hormone allows action of a second, one
has to occur before another does
a. Prolactin produces the milk and oxytocin allows the release of milk
AND ANSWERS ALL CORRECT
3 reflex mechanisms that stimulate hormone secretion Correct Answer: 1.Hormonal Stimulation:
stimulus for release of hormones by the binding of another hormone (eg the TSH from anterior
pituitary binds to thyroid gland to release TH)
2.Humoral Stimulation: release of hormone in response to change of blood nutrient levels (eg
blood glucose levels rise so insulin is released from pancreas, or fall and glucagon is released)
3.Neural Stimulation: direct stimulation from nervous system to endocrine gland (eg epinephrine
and norepinephrine by adrenal medulla during fight or flight)
Hormonal Stimulation Correct Answer: Stimulus for release of hormones by the binding of
another hormone (eg the TSH from anterior pituitary binds to thyroid gland to release TH)
Humoral Stimulation Correct Answer: release of hormone in response to change of blood
nutrient levels (eg blood glucose levels rise so insulin is released from pancreas, or fall and
glucagon is released)
Neural Stimulation Correct Answer: direct stimulation from nervous system to endocrine gland
(eg epinephrine and norepinephrine by adrenal medulla during fight or flight)
Steroids Correct Answer: lipid soluble molecules synthesized by cholesterol
1. Gonads (Estrogen, Progesterone, Testosterone)
2. Adrenal Cortex hormones (Corticosteroids like cortisol, mineralocorticoids, aldosterone)
Biogenic Amines Correct Answer: modified amino acids, water soluble (except thyroid)
1. Catecholamines (epinephrine and norepinephrine)
2. Thyroid Hormone → lipid soluble
3. Melatonin
Proteins Correct Answer: most hormones, small chains of amino acids, water soluble
1. Small peptides and large polypeptides
2. Glycoproteins
Local Hormones Correct Answer: DO NOT circulate in blood, so only affect either same cell
that produced them (autocrine) or neighboring cells (Paracrine)
1. Eicosanoids: synthesized through enzymatic cascade, Phospholipase A2 removes fatty acid
from phospholipid within the plasma membrane
--> prostaglandins
Prostaglandins Correct Answer: -Famous eicosanoid
-are diverse group: synthesized by most tissues in the body
-Stimulate pain receptors, reduce fever, increase inflammatory response
, Lipid soluble hormones: Correct Answer: Can cross membrane, but needs carrier protein while
circulating in blood, once unbound they can enter the nucleus
a. Has a longer half-life bc protected by carrier proteins
b. Once inside the cells, hormone binds to intracellular receptor either in nucleus of cytosol
c. Once bound, forms a hormone receptor complex which interacts with DNA directly in regions
called Hormone Response Element (HRE)
d. Initiates transcription/translation and production of a new protein
Water soluble hormones Correct Answer: Travel free in blood so shorter half-life, cannot enter
plasma membrane so binds to a membrane bound receptor
a. Second messengers begin a signal transduction pathway, which can cause an amplified signal
G protein activation by water-soluble hormones Correct Answer: a. Hormone binds to G-Protein
and activates it when GDP→ GTP
b. Active G-Protein is released and receptor moves along inside plasma mebrane, either to
activate or inhibit other intracellular cascades
Adenylate Cyclase Correct Answer: a. Hormone binds to G-Protein and activates it when
GDP→ GTP
b. Active G-Protein is released and receptor moves along inside plasma mebrane, either to
activate or inhibit other intracellular cascades
c. Using ATP, cAMP is created and activates protein kinase A, which will phosphorylate things
→ small concentration of hormone can have large effect on cell
Phospholipase C Correct Answer: i. Phospholipase C is enzyme activated by G-protein
ii. Splits into PIP2 and second messengers, DAG and IP3
iii. DAG activates kinase C
iv. IP3 leaves membrane and causes increase in Ca2 in cytosol which can directly affect or act as
3rd messenger
Upregulation Correct Answer: When the amount of hormones is small, then the number of
receptors increase in order to increase the sensitivity and obtain more of the hormones
--> Occurs with changes in development, cell cycle, and cell activity
Downregulation Correct Answer: If there is an abundent amount of hormone in the blood, then
the number of receptors decrease
--> Occurs with changes in development, cell cycle, and cell activity
Synergistic Hormone Interaction Correct Answer: hormones work together to have a greater
effect
a. 1+1=3, estrogen and progesterone together have a stronger effect than individually
Permissive Hormone Interaction Correct Answer: first hormone allows action of a second, one
has to occur before another does
a. Prolactin produces the milk and oxytocin allows the release of milk
