Unit 4 Exam BI 122 GRCC Periard Questions With Complete Solutions
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Course
GRCC
Institution
GRCC
Unit 4 Exam BI 122 GRCC Periard
Questions With Complete Solutions
What are the 3 classes of hormones and give an example of each. Lipid Derivatives -
example: Steroids (estrogen, testosterone, aldosterone, cortisol)
Eicosanoids (Prostaglandins = compounds that have hormone-like effects)
Amino ...
Peptide Hormones - Example: ADH (chain of 9 amino acids), GH (chain of 191 amino acids),
insulin, cholecystokinin (CCK), thymosin.
How are hormones inactivated? Also, how long are they active? They are inactivated
when: They bind to the target organ, They are absorbed and broken down by the liver or kidneys,
They are broken down in ECF by enzymes.
Hormones are functional for less than an hour in circulation.
Using the 6 steps discussed in class, explain how a steroid hormone (lipid soluble hormone)
works. (Explaining using Aldosterone as an example may help) 1st- Endocrine gland
secretes steroid hormone (For example Aldosterone).
, Unit 4 Exam BI 122 GRCC Periard
Questions With Complete Solutions
2nd- Steroid hormone (which is lipid soluble) easily diffuses through target cell's membrane and
enters its nucleus.
3rd- Steroid hormone combines with a receptor.
4th- Steroid hormone-receptor complex binds to DNA, which activates specific genes (activated
genes promote synthesis of mRNA) *Recall DNA doesn't leave the nucleus, so RNA takes the
"notes."
5th- mRNA enters cytoplasm and directs ribosomes to synthesize specific proteins
6th- Newly synthesized proteins bring about cellular changes, producing the hormone's effects.
Using the 6 steps discussed in class, explain how a non-steroid hormone (not lipid-soluble)
works. (Explaining using ADH may help) 1st- Endocrine gland secretes non-steroid
hormone (example ADH).
2nd- Body fluid carries hormone to its target cell.
, Unit 4 Exam BI 122 GRCC Periard
Questions With Complete Solutions
3rd- Non-steroid hormone combines with receptor site on its target cell, which activates G
protein (a membrane protein).
4th- G protein activates an enzyme (adenylate cyclase (The enzyme) ).
5th- Enzyme (adenylate cyclase) diffuses into cytoplasm and converts ATP cAMP (cyclic
adenosine monophosphate).
6th- cAMP activates another set of enzymes that lead to cellular changes, producing the
hormone's effects. (cAMP is quickly inactivated...so a sustained response depends on continued
hormone secretion).
Does positive or negative feedback mainly control hormone secretions in the body?
Methods of control mainly involve negative feedback (although there are a few examples
of positive feedback - example- oxytocin in labor).
How does the hypothalamus control the secretion of other hormones? Give an example using
GnRH. It Directly releases regulatory hormones (example- GnRH) that stimulate
endocrine cells in the anterior pituitary to release hormones (example - LH), which in turn cause
, Unit 4 Exam BI 122 GRCC Periard
Questions With Complete Solutions
other endocrine glands to release their hormones (example - sex hormones released by
testes/ovaries).
Besides the hypothalamus, what are the two other methods of controlling hormone secretion?
The two other methods of control are: Nervous System (Sympathetic (fight or flight)
Nervous System), & Changes in Internal Environment
What major gland does the hypothalamus control? The hypothalamus controls the
pituitary glands activities.
function and structure of posterior pituitary gland. Posterior pituitary (neurohypophysis)-
specialized neurons in the hypothalamus produce hormones (ADH, OT). These hormones travel
down axons to the posterior lobe and are stored there. Nerve impulses from hypothalamus cause
them to be released into blood.
function and structure of anterior pituitary Anterior pituitary (adenohypophysis)- releasing
hormones from the hypothalamus carried by a portal system (hypophyseal portal veins) control
its secretions. Most anterior lobe hormones stimulate the secretions of peripheral endocrine
glands.
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