A basic source of the confusion is that in the course of evolution whole
suites of genes have apparently been transferred sideways among the
major branches. Among animals, genes are passed vertically from parent
to child but single-celled creatures tend to engulf each other and
occasionally amalgamate into a corporate genetic entity. It has long
been argued that mitochondria, the tiny organelles that handle the
energy metabolism of eukaryotic cells, were once free-living bacteria
that were enslaved by an early eukaryote. Mitochondria still possess
their own, bacteria-like DNA but many of their genes have emigrated into
the eukaryotic cell's own DNA in the nucleus.
<span>Scientific method is a systematic procedure of making observations and for investigating phenomena. Scientific method is made up of the following steps; observe and state the problem, create your hypothesis, test your hypothesis or carry out experiment, analysis and record your data and then form a conclusion. Other scientists should be able to replicate your experiment anywhere in the world.</span><span />
Extinction refers to the eradication of an entire Species. Hope this helped!
Answer:
1. Thyroid gland is the endocrine gland that is involved here.
2. TSH stimulation test did not show an increase in the output of thyroid hormones secreted from thyroid glands which makes it a primary disorder. The determination of TSH or TRH gives an idea about hypothyroidism if it is due to feedback inhibition of the pituitary or absence of TSH hormone from the pituitary, however, Circulating levels of TRH not necessary.
3. The feedback loop involves the following:
TRH hormone secreted from the hypothalamus triggers the anterior pituitary to secret TSH that in turn triggers the relapsing of the T3 and T4 levels by the thyroid glands. If there is a low level of T3 and T4 hormones then negative feedback takes place and increases the TSH output.
4. symptoms:
Not able to uptake the iodide into the cells of the thyroid gland
Defects in the conversion of iodide to iodine
tyrosine molecule iodization
secretion of the hormones from the Tg molecules
Less TSH receptors on the gland.
5. The chronic TSH stimulation due to negative feedback may cause hypertrophy of the gland, results in goiter formation.
6. synthetic hormone therapy is known as Synthroid such asT4 (L-thyroxine).
