Steroid and thyroid hormones, Biology

Assignment Help:

Steroid and Thyroid Hormones

Cytoplasmic receptors for steroids are proteins with two subunits that bind to the steroid molecules. When both receptor sites are occupied by the steroid then the receptor-steroid complex migrates to the nucleus where one subunit ensures that the complex binds to the specific site on the chromatin. Then the receptor subunits separate and the other subunit interact directly with the adjacent region of DNA molecule resulting in the transcription of the DNA segment into mRNA.

Thyroid hormone acts in a similar manner except that the receptor is located in the nucleus. The major hormone secreted by thyroid is thyroxine (T4). It travels in blood attached to carrier proteins. Thyroid also secretes a small amount of triiodothyronine (T3). Carrier proteins have higher affinity for T4 and very little T4 is free in the plasma. Only the free T4 and T3 enter the cells. The rest of the bound T4 acts as a reservoir for slow release. The free T4 that enters the cell s also converted to T3 enzymatically. Therefore, T3 is the chemically more potent and active form of thyroid hormone.

552_Steroid and Thyroid Hormones.png

Figure:Steroid and Thyroid Hormones


Related Discussions:- Steroid and thyroid hormones

Explain early diastolic sound in diastolic, Explain Early Diastolic Sound i...

Explain Early Diastolic Sound in diastolic ? a) Opening snap (0s) of Rheumatic MS: High frequency sound. Generation of sound: Because of high LA pressure, the superior systolic

Botany homework troubles., The xylem and phloem of the plant could be descr...

The xylem and phloem of the plant could be described as the "circulatory system" of the plant. However there are key differences between vascular tissue in plants and our own circu

Diffusion of gases, Diffusion of Gases Gases diffuse from areas of hi...

Diffusion of Gases Gases diffuse from areas of higher partial pressure to areas of lower partial pressure. The diffusion along the partial pressure gradient ceases only when

What are restriction enzymes, What are restriction enzymes? How do these en...

What are restriction enzymes? How do these enzymes participate in the recombinant DNA technology? The Restriction enzymes, or restriction endonucleases, are enzymes specialized

From molecules to the first cell, From Molecules to the First Cell The ...

From Molecules to the First Cell The prebiotic conditions on the earth in all probability were volcanic eruptions, lightning and heavy rains. There was no trace of free oxygen

Explain disease motion sickness, Motion Sickness  The pathogenesis of m...

Motion Sickness  The pathogenesis of motion sickness is poorly under- stood. The prescription cholinergic blocker scopolamine in a patch or oral formulation can decrease sympto

How does the poison cyanide act upon the aerobic respiration, Q. How does t...

Q. How does the poison cyanide act upon the aerobic respiration? Cyanide is a poison that restrains the last cytochrome of the respiratory chain, interrupting the ATP formation

Explain about the freezing - method of food preservation, Explain about the...

Explain about the Freezing - method of food preservation? Freezing (-18°C to - 40°C): In freezing, water in food turns into ice and makes unavailable for reactions to occur, an

What is the tertiary structure of a protein, The tertiary protein structure...

The tertiary protein structure is a spatial conformation additional to the secondary structure in which the alpha helix or the beta-sheet folds up itself. The forces that stay the

Syngamy, Syngamy The pollen tube grows to a very limited extent in the...

Syngamy The pollen tube grows to a very limited extent in the synergid. It releases the contents either through a terminal or a subterminal pore. The contents include the two

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd