Moderate

How many iodine atoms are present in thyroxine T4?

Correct answer: B. 4

  • A. 3
  • B. 4
  • C. 2
  • D. 5

Explanation

The thyroid is a small, butterfly-shaped gland located at the front of the neck. It's part of the endocrine system and controls many of the body's important functions by producing and releasing (secreting) certain hormones such as thyroxine and triiodothyronine. Thyroxine is produced by attaching iodine atoms to the ring structure of proteins' tyrosine residues. Thyroxine T4 contains 4 iodine atoms, while tri-iodothyronine contains 3 iodine atoms.

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About Coordination and Control

Coordination depends on receptors, neurons, synapses and nerve impulses, with reflex actions traced through the reflex arc and the roles of major brain regions. Chemical coordination covers endocrine glands and hormones, including how hormones regulate growth, metabolism, reproduction and internal balance, unlike rapid nervous control.

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