PHAR 502 THYROID | QUESTIONS AND ANSWERS |
WITH COMPLETE SOLUTION.
What is the functional unit of the thyroid? Answer - thyroid follicle
Which molecule are T3 and T4 synthesized from? Answer - L-tyrosine
What is the bond angle between the pheny and tyrosyl groups? Answer - 90
degrees (perpendicular
T3 pKa Answer - 8.47
T4 pKa Answer - 6.73
T3 % ionized at physiologic pH Answer - 10%
T4 % ionized at physiologic pH Answer - 80%
T or F T3 transports in the blood easier than T3 due to it's ionized form at
physiological pH Answer - false. T4 is more ionized at physiological pH and thus
is more easily bound to albumin and other transport proteins
, What characteristic of T3 makes binding at target sites easiest? Answer -
Ability to Hydrogen Bond
What is the preferred way to treat hypOthyroidism Answer - T4 dosing
What is the function of thyroid peroxidase (TPO)? Answer - Addition of Iodide
onto tyrosine which is attached to thyroglobulin in the apical membrane
What is the most common form of Iodine? Answer - Iodide (I-)
Which two molecules can inhibit Iodide transport in thyroid cells Answer -
Perchlorate and Thiocyanate
What molecule regulates the Na/I symporter Answer - Thyroid Stimulating
Hormone
Where is the highest concentration of iodide found? Answer - Follicular Colloid
Which molecule catalyzes the coupling reaction between two DIT molecules
Answer - Thyroid Peroxidase (TPO)
Which molecule helps to Transport T3 and T4 in the blood? Answer -
Thyroxine-binding globulin (prefer T4)
Which molecule converts T4 to T3 in the tissue? Answer - Iodothyronine
deiodinases
What is reverse T3? Answer - Inactive form of T3 that is made from peripheral
conversion of T4 to T3
WITH COMPLETE SOLUTION.
What is the functional unit of the thyroid? Answer - thyroid follicle
Which molecule are T3 and T4 synthesized from? Answer - L-tyrosine
What is the bond angle between the pheny and tyrosyl groups? Answer - 90
degrees (perpendicular
T3 pKa Answer - 8.47
T4 pKa Answer - 6.73
T3 % ionized at physiologic pH Answer - 10%
T4 % ionized at physiologic pH Answer - 80%
T or F T3 transports in the blood easier than T3 due to it's ionized form at
physiological pH Answer - false. T4 is more ionized at physiological pH and thus
is more easily bound to albumin and other transport proteins
, What characteristic of T3 makes binding at target sites easiest? Answer -
Ability to Hydrogen Bond
What is the preferred way to treat hypOthyroidism Answer - T4 dosing
What is the function of thyroid peroxidase (TPO)? Answer - Addition of Iodide
onto tyrosine which is attached to thyroglobulin in the apical membrane
What is the most common form of Iodine? Answer - Iodide (I-)
Which two molecules can inhibit Iodide transport in thyroid cells Answer -
Perchlorate and Thiocyanate
What molecule regulates the Na/I symporter Answer - Thyroid Stimulating
Hormone
Where is the highest concentration of iodide found? Answer - Follicular Colloid
Which molecule catalyzes the coupling reaction between two DIT molecules
Answer - Thyroid Peroxidase (TPO)
Which molecule helps to Transport T3 and T4 in the blood? Answer -
Thyroxine-binding globulin (prefer T4)
Which molecule converts T4 to T3 in the tissue? Answer - Iodothyronine
deiodinases
What is reverse T3? Answer - Inactive form of T3 that is made from peripheral
conversion of T4 to T3
