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

Determine the types of neuropsychology, Determine the types of neuropsychol...

Determine the types of neuropsychology The practise in neuropsychology is roughly divided into two approaches. Some practitioners use standard comprehensive neuropsychological

Explain the culture media and its types, Explain the Culture Media and Its ...

Explain the Culture Media and Its Types? A culture medium (Pl. media), we already know, is a solid or liquid preparation containing all the nutrients required by microorganisms

How coacervates have facilitated emergence of life on earth, How could coac...

How could coacervates have facilitated the emergence of life on earth? Coacervates probably provided a nitid separation between an internal and an external environment and thus

Tranquillizers - psychological drug dependence, TRANQUILLIZER S - Thes...

TRANQUILLIZER S - These are the drugs that reduce tension and anxiety, bring calmness without inducing sleep. (i) Phenothiazines - These are anti psychotic drugs.

Protonephridia and metanephridia, Protonephridia and Metanephridia Ne...

Protonephridia and Metanephridia Nephridia take place in two major forms - the protonephridium and metanephridium. Protonephridia are found in flat worms. The protonephridial

Classification of chromatography -basic separation technique, Define Classi...

Define Classification of Chromatography - Basic Separation Technique Chromatography can be classified depending upon: Physiochemical principles/factors, The techniqu

What are their respective modes of transmission, What are some human diseas...

What are some human diseases caused by bacteria and what are their respective modes of transmission? The major human bacterial infections transmitted by respiratory secretions

Illustrate mitral valve orifice area, Q. Illustrate Mitral Valve Orifice Ar...

Q. Illustrate Mitral Valve Orifice Area? The normal mitral valve orifice in an adult is 4-5cm 2 when the valve is completely open in diastole. When the mitral valve orifice ar

Skeleton, biological significant of a skeleton

biological significant of a skeleton

Post-operative care of teeth, Post-operative care of teeth After implan...

Post-operative care of teeth After implant surgery, patients should be warned to expect:  Some swelling and possibly bruising.  Some discomfort which can usually be contr

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