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

Define classification of proteins on the basis of attributes, Define Classi...

Define Classification of proteins on the basis of attributes? Besides classifying proteins on the basis of soluble and insoluble, proteins have been further classified based on

Define the principle behind cyanmethemoglobin method, Define the Principle ...

Define the Principle behind Cyanmethemoglobin Method? The principle behind the cyanmethemoglobin method is as follow: Principle The haemoglobin is treated with a reagent con

Biosynthesis of hemes and chlorophylls, In animals, some of bacteria and fu...

In animals, some of bacteria and fungi, and the first step in tetrapyrrole synthesis is the condensation of the amino acid glycine with succinyl  CoA (an intermediate  of the citri

Explain the sa node cardiac muscle cells, Which of the following is true fo...

Which of the following is true for SA node cardiac muscle cells? A. An increase in the binding of norepinephrine to beta-adrenergic receptors in SA node cells will lead to an i

How does the absence of a nuclear envelope in prokaryotes, How does the abs...

How does the absence of a nuclear envelope in prokaryotes prevent prokaryotes from controlling gene expression by modifying RNA after transcription? Without a nuclear envelope

What are rna polymerase subunits, Each of the three eukaryotic RNA polymera...

Each of the three eukaryotic RNA polymerases has more subunits or 12 and so these are big complex enzymes. The genes encoding some of the subunits of each  eukaryotic  enzyme  show

Fundamental cardiac unit, The fundamental contractile unit is the sarcomere...

The fundamental contractile unit is the sarcomere. Each muscle cell apart from the nucleus, mitochondria and other structures contains parallel fibrils. Sarcomere is a subunit of t

Ethylene production - responses to infection, Ethylene production - Res...

Ethylene production - Responses to Infection Ethylene is also induced in response to infection. It is also known to be produced under other stress conditions like wounding

Growing roots from different parts of plants, Growing roots from different ...

Growing roots from different parts of plants Secure a box of sand and place it away from direct sunlight. Wet the sand thoroughly and keep it moist. Plant the following thi

Determine the amount of vasopressin, Consider the case of a rare mutant in ...

Consider the case of a rare mutant in which the concentration of solutes in the kidney medulla interstitial spaces is equal to the concentration of solutes in the liquid in the lum

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